Arcuate Nucleus Of Hypothalamus

Leptin injected twice daily for 4 days either into the right ventromedial hypothalamus (VMH) or into the right lateral cerebral ventricle (ICV) and using Real-Time Taqmantrade mark RT-PCR, mRNA expression levels of selected genes in the arcuate nucleus-median eminence (ARC-ME) complex were quantitatively measured.  

We conclude that 1) PPARgamma mRNA and protein are expressed in the hypothalamus, 2) neurons are the predominant source of PPARgamma in the CNS, although it is likely expressed by non-neuronal cell types as well, and 3) arcuate nucleus neurons that control energy homeostasis and glucose metabolism are among those in which PPARgamma is expressed..  

Expression of neuropeptide Y (Npy) heteronuclear (hn) RNA, an indicator of gene transcription, was significantly increased in the arcuate nucleus of rats 30min after insulin injection. Thus, Npy gene transcription in the arcuate nucleus increases rapidly in response to hypoglycemia, and both direct and indirect inputs are involved in the rapid upregulation..  

TCDD treatment also increased CRF and POMC mRNA levels in the hypothalamic paraventricular nucleus (PVN) and arcuate nucleus, respectively, in a dose- and time-dependent manner.  

However, the profile of CART-immunoreactive cells and/or fibers in the periventricular area (PeA), arcuate nucleus (ARC), perifornical area inclusive of lateral hypothalamus (LH) and tuber cinereum (TC), dorsomedial (DMH), and ventromedial (VMH) hypothalamus at the 0 h ethanol withdrawal time point was quite similar to that in the pair-fed control rats.  

2) After OVX, apparently fewer PRV-IR positive cells were found in some nuclei as medial septum nucleus (MSN), arcuate nucleus (ARC), diagonal band nucleus (DBN), paraventricular nucleus (PVN) which have close relation with endocrine activity (P<0.05); and rarely seen in ventromedial hypothalamus (VMH) and lateral preoptic area (LPO) (P<0.01).  

In the arcuate nucleus (ARC) of both species, kisspeptin cells appear to forward signals pertinent to negative feedback regulation of GnRH, although in the ewe it appears this population of Kiss1 cell is also responsible for positive feedback regulation of GnRH at the time of the preovulatory GnRH/LH surge.  

In Experiment 2, NPK-treated chicks had increased c-Fos immunoreactivity in the parvicellular division of the paraventricular nucleus and arcuate nucleus. Thus, we conclude that NPK is a regulator of chick appetite and the effects may be mediated directly in the arcuate nucleus and parvicellular division of the paraventricular nucleus..  

We further show that N-PCT increases the responsiveness of proopiomelanocortin anorexigenic neurons in the arcuate nucleus of the hypothalamus, and that stimulation of the de novo synthesis of prostaglandins is crucial for the central effects induced by N-PCT.  

Heavy P2X(5) receptor immunostaining was observed in the mitral cells of the olfactory bulb; cerebral cortex; globus pallidum, anterior cortical amygdaloid nucleus, amygdalohippocampal area of subcortical telencephalon; anterior nuclei, anteroventral nucleus, ventrolateral nucleus of thalamus; supraoptic nucleus, ventromedial nucleus, arcuate nucleus of hypothalamus; substantia nigra of midbrain; pontine nuclei, mesencephalic trigeminal nucleus, motor trigeminal nucleus, ambiguous nucleus, inferior olive, hypoglossal nucleus, dorsal motor vagus nucleus, area postrema of hindbrain; Purkinje cells of cerebellum; and spinal cord.  

In this paper, we tested the hypothesis that food deprivation will increase the expression of mu opioid receptors in the ventral medial hypothalamus and arcuate nucleus (VMH/ARC).  

Prepro-QRFP mRNA was significantly increased in the ventromedial nucleus/arcuate nucleus of the hypothalamus of rats fed a high fat diet compared to those fed a low fat diet, while GPR103 mRNA levels were unchanged.  

Other areas, including the suprachiasmatic nucleus, posterior paraventricular hypothalamic nucleus, posterior paraventricular thalamic nucleus, arcuate nucleus, and central amygdala, did not respond to 3 h sleep deprivation with a significant increase in c-Fos levels.  

One major population of kisspeptin immunoreactive cell bodies was found in the arcuate nucleus (ARC), where they extended from the middle of the nucleus to the premammillary recess.  

Double-labeling immunohistochemistry revealed colocalization of nesfatin with vasopressin and oxytocin in magnocellular neuroendocrine neurons, thyrotropin-releasing hormone, corticotropin-releasing hormone, somatostatin, neurotensin, and growth-hormone-releasing hormone in parvocellular neuroendocrine neurons, pro-opiomelanocortin (but not neuropeptide Y) in the arcuate nucleus and melanin-concentrating hormone (but not hypocretin) in the lateral hypothalamus.  

This nerve cell group is situated in the interstitial area between the arcuate nucleus and ventromedial nucleus of the hypothalamus, and is primarily oriented sagittally, in a spindle shape.  

Administration of the blocker Bcl-2 has been revealed to decrease functional activity both of dopaminergic neurons (Zona Incerta) and of dopaminergic neurosecretory cells (arcuate nucleus), in which a decrease of the tyrosine hydroxylase content was observed. The p53 inactivation also led to a decrease of activity of dopaminergic neurosecretory cells of arcuate nucleus, whereas activity of the proteins Zone Incerta did not change.  

The present study examined the effects of local injections of metergoline (MET, an antagonist of 5-HT1/2 receptors, 2 and 20 nmol) and 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT, selective 5-HT1A receptor agonist, 0.6 and 6 nmol) into the arcuate nucleus (ARC) and the lateral hypothalamus (LH), on ingestive and non-ingestive behaviors of female rats.  

In the hypothalamus of these mice, neurons in the arcuate nucleus exhibit intact responses to reduced fat mass and low circulating leptin levels, suggesting that defects in other components of the energy homeostasis system explain the phenotype of Tace(DeltaZn/DeltaZn) mice.  

Ghrelin-induced feeding behaviour is controlled by arcuate nucleus neurons that co-express neuropeptide Y and agouti-related protein (NPY/AgRP neurons).  

A cell signaling antibody microarray revealed that estradiol activated forty-two proteins in the arcuate nucleus of the hypothalamus (ARH).  

nocturnal administration of the C-terminal octapeptide of CCK (CCK-8) on (i) body weight and food intake, and (ii) STAT3 activation, by analyzing phosphorylated STAT3 (pSTAT3) immunostaining within the arcuate nucleus of the hypothalamus.  

Their immunoreactive processes extended into the arcuate nucleus, ventromedial hypothalamus and the median eminence.  

Results of immunohistochemistry showed that the integral grey values (IGV) of PKA of paraventricular nucleus (PVN), arcuate nucleus (ARC) and supraoptic nucleus (SON) of hypothalamus in CCI + EA 2 w group were significantly lower than those in normal control and CCI + EA 2 d groups (P<0.05).  

In OVX+E ewes, greater expression of kisspeptin and Kiss1 mRNA in the arcuate nucleus and lesser expression of RFRP (protein) in the dorsomedial nucleus of the hypothalamus were concurrent with the breeding season.  

areas that lack a BBB, the median eminence and its close relationship with the hypothalamic arcuate nucleus plays an important role in controlling the entry of blood-borne substances to neurons of the mediobasal hypothalamus. In order to clarify the nature of the BBB in the median eminence-arcuate nucleus complex, we have used immunohistochemistry and antisera to protein components of the BBB-(1) tight junctions, claudin-5 and zona occludens-1 (ZO-1); (2) endothelial cells: (a) all endothelial cells: rat endothelial cell antigen-1 (RECA-1), (b) endothelial cells at BBB: endothelial barrier antigen (EBA), glucose transporter 1 (GLUT1) and transferrin receptor (TfR), and (c) endothelial cells at CVOs: dysferlin; (3) basal lamina: laminin; (4) vascular smooth muscle cells: smooth muscle actin (SMA); (5) pericytes: chondroitin sulfate proteoglycan (NG2); (6) glial cells: (a) astrocytes: glial fibrillary acidic protein (GFAP), (b) tanycytes: dopamine- and cAMP-regulated phosphoprotein of 32kDA (DARPP-32), (c) microglia: CD11b. Neuronal cell bodies located in the ventromedial aspect of the arcuate nucleus were visualized by antiserum to agouti-related protein (AgRP). Some vessels in the ventromedial aspect of the arcuate nucleus lacked the BBB markers EBA and TfR, suggesting an absence of an intact BBB. These vessels may represent a route of entry for circulating substances to a subpopulation of arcuate nucleus neurons..  

The majority of gene expression changes are confined to two restricted areas: the dorsomedial posterior arcuate nucleus, and the ventral ependymal layer of the third ventricle.  

This review focuses on three in particular: 1) prostaglandins in the masculinisation of the preoptic area and control of male sexual behaviour; 2) GABA in the arcuate nucleus and potential control of the anterior pituitary; and 3) non-genomic activation of phosphotydolinositol 3 (PI3) kinase and glutamate in the ventromedial nucleus, which is relevant to the control of female reproductive behaviour.  

Injection of NPY-SAP into the rat arcuate nucleus (Arc) and basomedial hypothalamus (BMH) destroys two populations of NPY-receptor-expressing neurons important for the control of food intake and body weight, NPY and pro-opiomelanocortin (POMC) and cocaine and amphetamine related transcript (CART) neurons, and produces profound hyperphagia and obesity.  

In Experiment 4, central NPVF treatment was associated with decreased c-Fos immunoreactivity in the lateral hypothalamus, whereas c-Fos immunoreactivity in the dorsomedial nucleus, infundibular nucleus (homologue to the mammalian arcuate nucleus) and ventromedial nucleus was increased.  

We have recently found that, in the arcuate nucleus of the hypothalamus, a high proportion of POMC neurons express PACAP receptors. Central administration of PACAP induced c-Fos mRNA expression and increased the proportion of POMC neuron-expressing c-Fos mRNA in the arcuate nucleus. POMC mRNA level in the arcuate nucleus of PACAP-specific receptor (PAC1-R) knock-out mice was reduced as compared with wild-type animals.  

We reported in previous studies that glucocorticoids play a permissive role in the regulation of orexigenic neuropeptide Y (Npy) gene expression in the arcuate nucleus. In this study, we examined whether any cross talk occurs between glucocorticoids and AMPK signaling in the hypothalamus to regulate Npy as well as agouti-related peptide (Agrp) gene expression in the arcuate nucleus. In the hypothalamic organotypic cultures, the addition to the medium of the AMPK activator, 5-aminoimidazole-4-carboxamide-1-b-d-ribofuranoside, increased phosphorylated AMPK (p-AMPK) as well as phosphorylated acetyl-coenzyme A carboxylase (p-ACC) in the explants, accompanied by significant increases in Npy and Agrp gene expression in the arcuate nucleus. The incubation with dexamethasone (DEX) also activated AMPK signaling in the explants, accompanied by significant increases in Npy and Agrp gene expression in the arcuate nucleus. Furthermore, p-AMPK and p-ACC levels in the arcuate nucleus were significantly decreased in adrenalectomized rats compared with sham-operated rats, and a replacement of glucocorticoids reversed the AMPK signaling in adrenalectomized rats. Thus, our data demonstrated that glucocorticoids up-regulate the Npy and Agrp gene expression in the arcuate nucleus through AMPK signaling, suggesting that the activation of the hypothalamic APMK signaling by glucocorticoids might be essential to the energy homeostasis..  

Gut-glucose-sensitive c-Fos-positive cells of the arcuate nucleus colocalized with neuropeptide Y-positive neurons but not with proopiomelanocortin-positive neurons.  

Kisspeptin perikarya were found only in the mediobasal hypothalamus (MBH) almost exclusively in the posterior two-thirds of the arcuate nucleus.  

Leptin action has been most intensely investigated in the arcuate nucleus of the hypothalamus (ARC), which represents an important leptin target site.  

Stereologic analysis showed that there were significantly higher numbers of ERalpha-immunoreactive cells in ob/ob mice irrespective of sex when compared to wild-type (WT) in arcuate nucleus (ARH) and no significant change in ERbeta immunoreactive cell numbers in ARH or paraventricular nucleus (PVN).  

Here, we demonstrate that the anorectic effect of RSTN is associated with inappropriately decreased mRNA expression of orexigenic (agouti-related protein and neuropeptide Y) and increased mRNA expression of anorexigenic (cocaine and amphetamine-regulated transcript) neuropeptides in the arcuate nucleus of the hypothalamus.  

In the arcuate nucleus of the hypothalamus, the melanocortin pathway was also more strongly activated after the acute or chronic intake of high-protein meals.  

Leptin responsiveness was first detected in arcuate nucleus, where it was faint at P1 and evident from P5.  

In colchicine-treated rats, DYN immunoreactivity was demonstrated in many cell bodies of the arcuate nucleus (Arc).  

The androgen receptor (AR) was expressed strongly in the bed nucleus of the stria terminalis, the medial preoptic area, the arcuate nucleus, the ventromedial hypothalamic nucleus and the suprachiasmatic nucleus in the diencephalon.  

To explore the effect of refeeding on recovery of TRH gene expression in the hypothalamic paraventricular nucleus (PVN) and its correlation with the feeding-related neuropeptides in the arcuate nucleus (ARC), c-fos immunoreactivity (IR) in the PVN and ARC 2 h after refeeding and hypothalamic TRH, neuropeptide Y (NPY) and agouti-related protein (AGRP) mRNA levels 4, 12, and 24 h after refeeding were studied in Sprague-Dawley rats subjected to prolonged fasting.  

In obese rats, amylin pretreatment partially restored hypothalamic leptin signaling (pSTAT3 immunoreactivity) within the ventromedial, but not the arcuate nucleus and up-regulated basal and leptin-stimulated signaling in the hindbrain area postrema.  

The arcuate nucleus and paraventricular nucleus showed a significant reduction in CART mRNA expression in DIO mice compared to DR mice on the HF diet (-19.6%, p=0.019; -26.1%, p=0.003); whilst a profound increase in CART mRNA expression was observed in the dorsomedial nucleus and lateral hypothalamic area (+44.5%, p=0.007; +37.4%, p=0.033).  

NK1 receptor binding in the agranular insular cortex and arcuate nucleus of the hypothalamus and NK2 receptor binding in the amygdala was lower in preshocked rats than in controls.  

In the arcuate nucleus, a major regulator of anterior pituitary function, estradiol increases GABA synthesis, altering the morphology of neighboring astrocytes and reducing formation of dendritic spines synapses.  

The majority of the EM1/FG and EM2/FG double-labeled neurons in the hypothalamus were distributed in the dorsomedial nucleus, areas between the dorsomedial and ventromedial nucleus, and arcuate nucleus; a few were also seen in the ventromedial, periventricular, and posterior nucleus.  

In the arcuate nucleus of adult female rats, 17beta-estradiol triggers synaptic remodeling, resulting in a decrease in the number of inhibitory synaptic inputs, an increase in the number of excitatory synapses, and an enhancement of the frequency of neuronal firing. In the present paper, we studied the specificity of hormonal effects by determining the changes in synaptic connectivity of tyrosine hydroxylase (TH) immunoreactive (IR) neurons in the arcuate nucleus.  

Since normal growth of the offspring depends on adequate maternal nursing and care, we evaluated the effect of 2,4-D on rat maternal behavior as well as the dam's monoamine levels in arcuate nucleus (AcN) and serum prolactin (PRL) levels.  

Neuropeptide Y, agouti-related peptide, proopiomelanocortin (POMC), cocaine- and amphetamine-regulated transcript (CART), and insulin receptor mRNAs were all localized in the hypothalamic arcuate nucleus (ARC) of all fetuses, whereas leptin receptor mRNA was expressed more abundantly in the ventromedial hypothalamic nucleus.  

Anatomical evidence suggests that the ventromedial arcuate nucleus (vmARC) is a route for circulating hormonal communications to the suprachiasmatic nucleus (SCN).  

14 and 45 days after the toxin administration there were determined concentration of prolactine in peripheral blood by methods of immunoenzyme and radioimmunological analyses as well as the DA amount in the arcuate nucleus by the method of highly efficient liquid chromatography with electrochemical detection. In a part of the animals, slices were prepared from the mediobasal hypothalamus (arcuate nucleus and medial eminence) and perfused with Krebs-Ringer medium; then the DA concentration was determined in the slices and in the incubation medium. 14 days after the neurotoxin administration there were revealed an increase of blood prolactine concentration and a decrease of DA concentration in the arcuate nucleus in vivo as well a decrease of the total DA amount in the slices and incubation medium in experiments in vitro. This, the obtained data indicate that the hyperlactinemia and DA deficit appearing during degeneration of the arcuate nucleus DA-ergic neurons seem to be compensated due to an enhancement of DA synthesis by non-dopaminergic monoenzyme neurons of arctuate nucleus..  

Among the multiple brain regions containing leptin-sensitive Stat3 sites, cells expressing feeding-related neuropeptides in the arcuate nucleus of the hypothalamus have received much of the focus.  

Alpha-melanocyte stimulating hormone (alpha-MSH) in the arcuate nucleus also plays a role in the energy homeostasis, possessing anorexigenic effects. To investigate the participation of neuropeptides involved in the regulation of food intake during endotoxemia, we administrated lipopolysaccharide (LPS) in sham-operated and adrenalectomized (ADX) male Wistar rats to evaluate food intake, hormone responses and Fos-CRF and Fos-alpha-MSH immunoreactivity in the PVN and arcuate nucleus, as well as CRF and POMC mRNA expression in these hypothalamic nuclei. In sham-operated rats, treatment with LPS (100 microg/kg) showed lower food intake, higher plasma ACTH and corticosterone levels, as well as an increase in Fos-CRF double labeled neurons and CRF mRNA expression in the PVN, with no changes in Fos-alpha-MSH immunoreactivity and POMC mRNA expression in the arcuate nucleus, compared to saline treated rats. After LPS treatment, ADX rats showed further increase in plasma ACTH levels, marked decrease of food intake, higher Fos-CRF immunoreactive neurons in the PVN and CRF mRNA expression, as well as an increase in Fos-alpha-MSH immunoreactivity and POMC mRNA expression in the arcuate nucleus, compared to sham-operated rats treated with LPS.  

In the hypothalamus of juvenile and middle-aged rats that were raised in control (10 pups) or FR litters (20 pups), gene expression was investigated for neuropeptide Y (NPY), agouti-related protein (AgRP), proopiomelanocortin (POMC), and cocaine- and amphetamine-regulated transcript (CART) in the arcuate nucleus (ARC); CRH and TRH in the paraventricular nucleus; and melanin-concentrating hormone (MCH) and orexin in the lateral hypothalamic area.  

During adult reproductive life, the glial cells participate in the transient remodeling of neuronal connectivity in the preoptic area, the arcuate nucleus, the median eminence, and other brain regions involved in the control of reproduction.  

Moreover, an increase in the numbers of alpha-MSH positively immunostained neural cells in the hypothalamic arcuate nucleus (ARC), as well as a significant decrease in the numbers of neural cells positively immunostained for MC4-R in the paraventricular nucleus (PVN), without changes in lateral hypothalamic area (LHA), were observed.  

BACKGROUND: We have previously shown that developing beta-endorphin neurons, in the arcuate nucleus of the hypothalamus become increasingly apoptotic when exposed to ethanol. As in the previous study we have observed an involvement in transforming growth factor beta 1 (TGF-beta1) in mediation of the apoptotic process, the present study was conducted to determine the ethanol-induced changes in this apoptotic regulatory peptide signaling in the arcuate nucleus of the hypothalamus of neonatal rats. RESULTS: Ethanol exposure increased apoptotic death of beta-endorphin neurons in the arcuate nucleus of the hypothalamus. CONCLUSIONS: These results suggest that ethanol exposure increases TGF-beta1 signaling involving Bcl2 and Rb repression that may lead to apoptotic death of cells including beta-endorphin neurons in the arcuate nucleus of the hypothalamus..  

The homeodomain transcription factor Orthopedia (Otp) is expressed in several separate hypothalamic sites: the paraventricular nucleus, perimammillary region and arcuate nucleus. Other positive neuronal populations were observed in the arcuate nucleus and oblique perimammillary band.  

The dorsomedial nucleus of the hypothalamus (DMH) is innervated by projections from other brain areas being part of the network of nuclei controlling energy homeostasis, among others NPY/AgRP-positive fibers arising from the arcuate nucleus (ARC).  

formalin injection was located in the arcuate nucleus of the hypothalamus. In the same manner, beta-endorphin immunoreactivity was also increased in the hypothalamic arcuate nucleus. formalin injection was mainly located in the arcuate nucleus of hypothalamus in which cells containing beta-endorphin after s.c. In conclusion, POMC mRNA expression in the arcuate nucleus of the hypothalamus was increased by inflammatory pain stimuli, in which pERK1/2, pCaMK-IIalpha and NFkappaB may play an important role in the expression of the hypothalamic POMC gene and beta-endorphin expression..  

This delay was partly related to 5-15% decreased hyperphagia, which was not accompanied by decreased arcuate nucleus NPY or increased POMC mRNA expression, although expression was altered by obesity.  

Prolactin stimulates tuberoinfundibular dopamine neurons in the arcuate nucleus of the hypothalamus, mediated by signal transducer and activator of transcription 5b (STAT5b). Suppressors of cytokine signaling (SOCS) proteins inhibit STAT-mediated signaling, and SOCS mRNAs are specifically elevated in the arcuate nucleus during late pregnancy. Early progesterone withdrawal caused an early increase in prolactin secretion, and increased SOCS-1 and -3 and cytokine-inducible SH2-containing protein (CIS) mRNA levels in the arcuate nucleus. SOCS-1 and -3 and CIS mRNA levels in the arcuate nucleus were significantly increased by estrogen or prolactin, whereas progesterone treatment reversed the effect of estrogen. Results demonstrate that estrogen and prolactin can independently induce SOCS mRNA in the arcuate nucleus and that this effect is negatively regulated by progesterone.  

Leptin, an adipocyte-derived hormone, acts on hypothalamic neurons located in the arcuate nucleus (ARC) of the hypothalamus to regulate energy homeostasis.  

Chicks treated with ICV OXM had decreased c-Fos immunoreactivity in the regio lateralis hypothalami, but the nucleus infundibuli hypothalami (homologue to the mammalian arcuate nucleus) had increased c-Fos immunoreactivity.  

We now hypothesized that Bsx, which is expressed in the dorsomedial and arcuate nucleus (ARC) of the hypothalamus, is regulated by afferent signals in response to peripheral energy balance.  

Here, we report that loss of Ubb led to a progressive degenerative disorder affecting neurons within the arcuate nucleus of the hypothalamus.  

In both vehicle-treated and euhydrated rats, AM2-LI neurons were observed in the hypothalamus and brainstem, including in the organum vasculosum of the lamina terminalis, the median preoptic nucleus, the supraoptic nucleus (SON), the paraventricular nucleus (PVN), the ventromedial hypothalamic nucleus, the arcuate nucleus, the locus coeruleus, the nucleus of the tractus solitarius and the nucleus ambiguus.  

A major neuroendocrinological effect of calorie restriction (CR) is induction of neuropeptide Y (NPY) in the arcuate nucleus (ARC).  

Although food intake was not significantly reduced in rats treated with acarbose, the acarbose-treated rats had lower NPY expression in the arcuate nucleus.  

PYY(3-36), the major circulating form of the peptide, is thought to reduce food intake in humans and rodents via high-affinity binding to the autoinhibitory neuropeptide Y (NPY) receptor within the arcuate nucleus.  

We examine their reproductive role acting on the classic metabolic pathways of the arcuate nucleus, NPY/AgRP and POMC/CART neurons, and the newly identified kisspeptin network.  

The hypothalamic arcuate nucleus is an important target for metabolic and hormonal signals controlling food intake. Similar to refeeding, it also reversed the fasting-induced activation in the arcuate nucleus. Therefore, an increase in blood glucose might be an important feeding-related signal acting via the arcuate nucleus to oppose orexigenic stimuli..  

High fat feeding of mice increased PTP1B expression 1.5- to 7-fold in adipose tissue, liver, skeletal muscle, and arcuate nucleus of hypothalamus. TNFalpha administration in mice increased PTP1B mRNA 1.4- to 4-fold in adipose tissue, liver, skeletal muscle, and hypothalamic arcuate nucleus and PTP1B protein 2-fold in liver.  

The arcuate nucleus of the hypothalamus (ARH) is a key site for the regulatory actions of leptin in adults, and this same hormone is required for the normal development of ARH projections to other parts of the hypothalamus.  

The leptin receptor (Lepr) is expressed in discrete regions of the brain; among the sites of highest expression are several mediobasal hypothalamic nuclei known to play a role in energy homeostasis, including the arcuate nucleus, the ventromedial hypothalamic nucleus (VMH), and the dorsomedial hypothalamic nucleus. Although most studies have focused on leptin's actions in the arcuate nucleus, the role of Lepr in these other sites has received less attention.  

The arcuate nucleus of the hypothalamus (ARH) is a key component of hypothalamic pathways regulating energy balance, and leptin is required for normal development of ARH projections.  

c-Fos immunohistochemistry revealed that DMH CCK increased the number of c-Fos positive cells in the paraventricular nucleus (PVN), arcuate nucleus, suprachiasmatic nucleus and retrochiasmatic area as well as in the contralateral DMH.  

Temporal effects on expression of energy balance genes were restricted to long-form leptin receptor in the arcuate nucleus and ventromedial nucleus, where similar diurnal expression profiles were observed, and melanocortin-4 receptor in the paraventricular nucleus; these effects were only observed in LD hamsters.  

Specific binding was identified in the appetite-regulating arcuate nucleus, ventromedial hypothalamic nucleus, paraventricular nucleus, dorsomedial hypothalamic nucleus and the lateral hypothalamic area corresponding to the previously reported distribution pattern of GHS-R mRNA.  

We also found a strong negative correlation of the FTO expression level with the expression of orexigenic galanin-like peptide, which is mainly synthesized in the arcuate nucleus.  

In addition, ghrelin stimulates appetite by acting on the hypothalamic arcuate nucleus, a region known to control food intake.  

Fasting activates expression of orexigenic peptides from the arcuate nucleus, increases corticosterone while reduces leptin, and pro-TRH mRNA levels despite low serum thyroid hormone concentration (tertiary hypothyroidism).  

Leptin regulates energy balance and glucose homeostasis, at least in part, via activation of receptors in the arcuate nucleus of the hypothalamus located in proopiomelanocortin (POMC) neurons.  

While well-known LRb-expressing neurones within the arcuate nucleus of the hypothalamus mediate crucial effects on satiety and energy expenditure, other populations of LRb-expressing neurones in the ventral tegmental area and elsewhere likely control the mesolimbic dopamine system.  

Density of NPY-stained fiber varicosities was drastically increased in the external, but not the internal, zone of dexamethasone-injected group, coinciding with the increased NPY hybridization signal level in the arcuate nucleus.  

Sulpiride induced only SOCS-1 in the medial preoptic area, where GnRH neurons are regulated, but in the arcuate nucleus and choroid plexus, PRL-R, SOCS-3, and CIS mRNA levels were also induced.  

Agouti-related protein (AgRP) is a key orexigenic neuropeptide expressed in the hypothalamic arcuate nucleus and a marker for neurons conveying hormonal signals of hunger to the brain. At P21, many strongly AgRP-positive cell bodies were observed in the anx/anx arcuate nucleus vs.  

We have characterized, in free-feeding rats, the effect of CCK-8 on 1) food intake, BW, and adiposity; 2) skeletal muscle metabolism; 3) leptin signaling pathway within the arcuate nucleus of the hypothalamus; and 4) the permeability of brain barriers to leptin.  

Galanin-mediated modulation of the arcuate nucleus (Arc) neurons is thought to be involved in the regulation of feeding behavior, hormone secretion, and reproduction.  

Neuropeptide Y (NPY) and melanocortin neurons in the arcuate nucleus, a primary energy homeostatic center in adults, do not fully innervate the paraventricular nucleus (PVN) until the third postnatal week.  

In the present study, we investigated the differential effects of ES or PS on pain behaviors or on c-Fos immunoreactivity (IR) in the paraventricular nucleus (PVN) or arcuate nucleus (ArcN) using electrical footshock-witness model.  

Rats received an anorexigenic dose of PYY(3-36), and the number of neurons expressing Fos, an indicator of neuronal activation, was determined in anterior hypothalamus (AH), arcuate nucleus (ARC), dorsomedial hypothalamus (DMH), lateral hypothalamus (LH), ventromedial hypothalamus (VMH), central nucleus of the amygdala (CeA), area postrema (AP), and caudal medial nucleus tractus solitarius (cmNTS), commissural NTS (cNTS), and gelatinosus NTS (gNTS).  

The hypothalamic arcuate nucleus (Arc) is the presumed target site for the orexigenic hormone ghrelin, which is secreted from the stomach during fasting.  

Experiments in which the arcuate nucleus was damaged by an excitotoxic lesion revealed that hypothalamic KiSS-1 mRNA was significantly reduced, whereas FAT levels were unaffected, suggesting that regulation of KiSS-1 in FAT is independent of the hypothalamus.  

Ghrelin, an orexigenic hormone, directly activates neuropeptide (NPY) neurons in the hypothalamic arcuate nucleus (ARC), and thereby stimulates food intake.  

Adult Sprague Dawley rats were ovariectomized and chronically implanted with electrodes in the arcuate nucleus to record the characteristic increases in hypothalamic multiunit electrical activity volleys coincident with the initiation of each LH pulse measured in peripheral blood and/or indwelling cardiac catheters for the collection of blood samples (25 microl) every 5 min for 6-7 h for the measurement of LH.  

From NTS afferents fibers project to the arcuate nucleus (ARC), where satiety signals are integrated with adiposity signals, namely leptin and insulin, and with several hypothalamic and supra-hypothalamic inputs, thus creating a complex network of neural circuits which finally elaborate the individual response to a meal.  

Extracellular discharges of neurons within the medial preoptic area, the arcuate nucleus and the paraventricular nucleus of the hypothalamus (AP: 4.0-9.0 mm, R: <1.0 mm, L: <2.0 mm) were recorded by using glass micro-pipettes in anesthetized rats (10% urethane).  

Immunocytochemical study confirmed impaired p-STAT3 activation in various hypothalamic areas, including the arcuate nucleus.  

Leptin is the crucial adipostatic hormone that controls food intake and body weight through the activation of specific leptin receptors (OB-R) in the hypothalamic arcuate nucleus (ARC).  

An examination of neuropeptide Y, proopiomelanocortin, and agouti-related peptide gene expression in the arcuate nucleus revealed that BRS-3 KO mice have some deficits in their response to energy regulatory signals.  

In an effort to elucidate the mechanism of this effect, we examined the chemical phenotype of 5-HT(2C)R-expressing neurons in a critical brain region affecting feeding behavior, the arcuate nucleus of the hypothalamus. We show that 5-HT(2C)Rs are coexpressed with neurons containing proopiomelanocortin, known to potently affect appetite, in the arcuate nucleus of the hypothalamus of the mouse.  

This state of leptin resistance is associated with impaired activation of the leptin-induced Janus activating kinase (JAK)/signal transducer and activator of transcription (STAT) signalling pathway in the ventromedial nucleus of the hypothalamus (VMH) and arcuate nucleus, and reduced expression of leptin receptor mRNA in the VMH.  

Despite elevated serum leptin, neuropeptide Y and agouti related peptide mRNA in the arcuate nucleus are not suppressed and may even be increased during pregnancy. LepR mRNA and leptin-induced pSTAT3 expression, however, are relatively normal in the arcuate nucleus. Injecting alpha-melanocyte-stimulating hormone (alpha-MSH) into the brain, to bypass the first-order leptin-responsive neurons in the arcuate nucleus, also fails to suppress food intake during pregnancy, suggesting that pregnancy is also a melanocortin-resistant state.  

This regulation might contribute to region-specific changes in neuronal excitability in the hypothalamic arcuate nucleus and to the integration of neuronal responses that influence homeostatic functions..  

The present study aimed at examining the impact of maternal undernutrition on leptin plasma levels in newborn male rats and on the arcuate nucleus proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons that are major leptin targets.  

PACAP mRNA-containing cell bodies were demonstrated in high numbers in the ventromedial hypothalamic nucleus (VMH) and in lower numbers in the arcuate nucleus (Arc).  

These regions include the arcuate nucleus, dorsomedial hypothalamus, suprachiasmatic nucleus, dorsal lateral geniculate nucleus and tuberomammillary nucleus.  

Gal-R2 was expressed in several regions of the hypothalamus (supraoptic nucleus, paraventricular nucleus, ventromedial nucleus, arcuate nucleus) but not as widely expressed as Gal-R1.  

In both groups the dorsomedial nucleus of the hypothalamus and arcuate nucleus, involved in energy balance, exhibited increased c-Fos expression 24 h after the last meal, while only RF rats exhibited low c-Fos expression in the SCN.  

Studies of wild-type mice indicate that Fto messenger RNA (mRNA) is most abundant in the brain, particularly in hypothalamic nuclei governing energy balance, and that Fto mRNA levels in the arcuate nucleus are regulated by feeding and fasting.  

In both cases, the changes in SI recorded in the hypothalamic arcuate nucleus preceded the effect of these peptides on food intake.  

Terminally, the 6-wk-Ex/7-wk-Sed rats had a 55% increase in arcuate nucleus proopiomelanocortin mRNA expression vs.  

The correlation between male sexual behavior and catecholamine levels in the medial preoptic area (MPOA) and arcuate nucleus (ARN) was studied in middle-aged rats.  

The arcuate nucleus of the hypothalamus is the main POMC producing cell group in brain and innervates several areas of the limbic system and brainstem.  

To better understand the neural mechanisms underlying torpor, Siberian hamster pups were postnatally treated with saline or MSG to ablate arcuate nucleus neurons that likely possess leptin receptors. In experiment 1, even though other photoperiodic responses persisted, MSG-induced arcuate nucleus ablations prevented the photoperiod-dependent torpor observed in saline-treated Siberian hamsters. We conclude that 1) arcuate nucleus mechanisms mediate photoperiod-induced torpor, 2) food-restriction-induced torpor may also be reduced by MSG treatments, and 3) arcuate nucleus neurons make an important, albeit partial, contribution to 2DG-induced torpor-like hypothermia..  

We report that intracerebroventricular (ICV) injection of leptin, concomitant with inhibiting AMP-activated kinase (AMPK), activates acetyl-CoA carboxylase (ACC), the key regulatory enzyme in fatty acid biosynthesis, in the arcuate nucleus (Arc) and paraventricular nucleus (PVN) in the hypothalamus.  

GALP mRNA was first detected in the arcuate nucleus (ARC) on day 8.  

The hypothesis that unexplained stillbirth arises in a similar manner as the sudden infant death syndrome (SIDS) is based in part on shared neuropathologic features between the two entities, including hypoxic-ischemic lesions such as white matter and brainstem gliosis, as well as aplasia or hypoplasia of the arcuate nucleus on the ventral surface of the medulla. The arcuate nucleus is the putative homologue of the respiratory chemosensory region at the ventral medullary surface in animals that is involved in central chemosensitivity. To determine arcuate nucleus pathology in stillbirth, and its co-occurrence with evidence of hypoxia-ischemia, we reviewed brain specimens from the archives of our hospitals from 22 consecutive stillbirths from 22 to 41 gestational weeks. In 12 brains, we observed nuclear karyorrhexis and/or pyknosis with cytoplasmic hypereosinophilia in neurons in the arcuate nucleus in both explained (n=8) and unexplained (n=4) cases (54.5% of total cases). The degree of gliosis in the region of the arcuate nucleus was variable across all cases, without statistically significant differences between groups with and without arcuate nucleus necrosis. Other lesions in association with (n=14) and without (n=8) arcuate nucleus abnormalities were diffuse cerebral white matter gliosis, periventricular leukomalacia (PVL), and neuronal necrosis in the hippocampus, basal ganglia, thalamus, basis pontis, and brainstem tegmentum. Our findings suggest that neuronal pathology in the arcuate nucleus may be both developmental (13.6%) and acquired (54.5%). The association of neuronal necrosis and apoptosis in the arcuate nucleus with systemic entities involving fetal ischemia, and with other brain lesions consistent with ischemia, e.g., cerebral white matter gliosis, suggests that ischemia plays a role in the arcuate nucleus damage as well. The role of arcuate nucleus pathology in the pathogenesis of fetal demise remains to be determined..  

Using triple-label immunofluorescent techniques, the present studies explored potential sex differences in the density of these projections within three hypothalamic sites: the VMNvl, the arcuate nucleus (ARC), and the dorsomedial nucleus of the hypothalamus.  

Although ghrelin-containing cell bodies have been reported to localize in the hypothalamic arcuate nucleus, the published results present large discrepancies regarding the localization of ghrelin-positive cell bodies in the brain. Double immunostaining revealed that GFP-like immunoreactivity was co-localized with ghrelin-like immunoreactivity in the stomach of these animals, while EGFP fluorescence was clearly demonstrated in the hypothalamic arcuate nucleus by confocal laser microscopy.  

The ventromedial nucleus of the hypothalamus (VMN) and the arcuate nucleus (ARC) are two centres regulating energy balance and food intake, but inter-connectivity of these nuclei is not well defined in non-rodent species.  

Several unique features of the arcuate nucleus of the hypothalamus may contribute to the severity of cellular leptin resistance in this region.  

Gastrectomy had little effect on the expression of these genes, with the exception of NPY mRNA in the arcuate nucleus that was increased. Two weeks gavage treatment with the ghrelin mimetic, MK-0677, to rats increased NPY and POMC mRNA in the arcuate nucleus and MCH mRNA in the lateral hypothalamus.  

The synaptic relationships between POMC- and ghrelin-containing neurons in the hypothalamic arcuate nucleus were studied using double-immunostaining methods at the light and electron microscope levels.  

The ovarian steroid hormone, estradiol, is one of several peripheral metabolic signal modulators that are integrated at the level of the arcuate nucleus of the hypothalamus (ARH), and is implicated in the control of ARH neuropeptides that maintain energy balance, including neuropeptide Y (NPY) and proopiomelanocortin (POMC).  

Synaptic relationships between ghrelin-like immunoreactive axon terminals and other neurons in the hypothalamic arcuate nucleus (ARC) were studied using immunostaining methods at the light and electron microscope levels.  

Galanin concentrations were significantly lower in di/di rats than in di/+ rats in the paraventricular nucleus (-56%; P<0.001), but not in the arcuate nucleus.  

Furthermore, effects on insulin sensitivity and expression of NPY, agouti-related protein (AgRP), and pro-opiomelanocortin in the arcuate nucleus were studied. This resulted in obesity characterized by increased fat mass; elevated plasma insulin, leptin, and adiponectin; decreased AgRP expression in the arcuate nucleus; and decreased insulin sensitivity; whereas plasma corticosterone was unaffected.  

GALP is produced in the hypothalamic arcuate nucleus, an area containing, amongst other neuron types, two populations of neurons in which we were interested: a population of GALP-containing neurons which regulate energy balance and reproduction, and a second population consisting of tuberoinfundibular dopaminergic neurons which suppress prolactin secretion from the adenohypophysis. To characterize morphologically the relationship between GALP and dopamine-containing neurons in the arcuate nucleus, a double immunofluorescence study was performed on cryosections from rat brain. Immunohistochemical double labeling studies revealed that GALP-immunoreactive nerve fibers made direct contact on tyrosine hydroxylase (TH)-containing neuronal cell bodies in the arcuate nucleus.  

Recent studies have shown that site-specific injection of ghrelin directly into the dorsal vagal complex (DVC) of rats is equally as sensitive in its orexigenic response to ghrelin as the arcuate nucleus of the hypothalamus (ARC).  

In interbout awake animals, we demonstrated the activation of hypothalamic neurons located in the arcuate nucleus and the dorsolateral hypothalamus, areas involved in food intake.  

BAT thermogenesis is governed by the sympathetic nervous system (SNS), whose activity is controlled by neurons comprised in various brain regions, which include the paraventricular hypothalamic nucleus (PVH), the arcuate nucleus (ARC) and the lateral hypothalamus (LH).  

The rapid estrogen effect on intracellular calcium oscillations was characterized in neurons of the arcuate nucleus.  

The 16-h photoperiod also had the largest effect on expression of circadian (per1) and neuroendocrine output (betaTSH) genes in the pars tuberalis and on kisspeptin gene expression in the arcuate nucleus of the hypothalamus, which modulates reproductive activity.  

A long-loop pathway involving the arcuate nucleus (ARC), ventrolateral periaqueductal gray, and rostral ventrolateral medulla (rVLM) is involved in sympathoinhibitory cardiovascular EA effects.  

Two distinct groups of neurons in the arcuate nucleus accept and process the afferent information provided by leptin produced by white adipocytes in proportion to their mass.  

Despite the decreased body weight, neuropeptide Y expression in the arcuate nucleus was significantly decreased, whereas pro-opiomelanocortin expression was significantly increased by baclofen treatment. These data demonstrate that the inhibitory effects of baclofen on body weight in the obese mice were mediated via the arcuate nucleus at least partially, and suggest that GABA(B) agonists could be a new therapeutic reagent for obesity..  

In adults, the adipocyte-derived hormone, leptin, regulates food intake and body weight principally via the hypothalamic arcuate nucleus (ARC).  

ICV administration of NMS increased proopiomelanocortin (POMC) mRNA expression in the arcuate nucleus (Arc) and corticotropin-releasing hormone mRNA in the paraventricular nucleus, and induced c-Fos expression in the POMC neurons in the Arc.  

Both the transcript and protein of MTMR9 were detected in the rodent lateral hypothalamic area as well as in the arcuate nucleus, and the protein co-existed with orexin, melanin concentrating hormone, neuropeptide Y and proopiomelanocortin.  

Insulin-associated changes in c-Fos(+) cell numbers were evident in the arcuate nucleus, bed nucleus of the stria terminalis and substantia nigra pars compacta, concomitant with elevated leptin levels and reduced chow intake.  

Animals were sacrificed on dioestrous, days 12, 19 and 21 of pregnancy and day 5 of lactation, and the proportion of TIDA neurones expressing ERalpha or PR, as well as the total number of PR expressing cells within the arcuate nucleus, was determined.  

Moreover, to determine possible mechanisms involved in parity-mediated changes in prolactin secretion, both dopamine utilisation within the arcuate nucleus/median eminence and expression of dopamine D(2) receptor mRNA (short and long forms) in the anterior pituitary were measured across the afternoon of pro-oestrous in reproductively experience and inexperienced females.  

In ewes, the majority of hypothalamic kisspeptin neurons are found in the arcuate nucleus (ARC), with a smaller population located in the preoptic area.  

In the CNS, cell bodies for POMC are mainly located in the arcuate nucleus of the hypothalamus and the nucleus tractus solitarius of the brainstem.  

In addition, blockade of mGluR1a in the arcuate nucleus of the hypothalamus resulted in a significant attenuation of estradiol-induced MOR internalization, leading to diminished female sexual behavior.  

Here we demonstrate that leptin stimulates the phosphorylation of STAT5 and ribosomal protein S6 in the hypothalamic arcuate nucleus in mice.  

PRV-labeled neurons were localized in paraventricular nucleus, supraoptic nucleus and arcuate nucleus following injections in both the perirenal and the subcutaneous adipose tissue depots.  

Interestingly, WDR6 gene expression in the hypothalamic arcuate nucleus was decreased by caloric restriction, and in growth hormone (GH)-antisense transgenic rats, both of which are associated with an increased life span.  

Our previous analysis revealed apoptosis of dopaminergic neurons in the arcuate nucleus (Arc) and medial preoptic area (MPO) of 1-year-old male ArKO mice.  

These animals exhibited a reduced food intake and body weight associated with an increase of CART expression in the arcuate nucleus (ARC).  

In INP sheep, LH output correlated positively with adiposity and plasma and CSF insulin concentrations and negatively with orexigenic neuropeptide Y gene expression in the hypothalamic arcuate nucleus (ARC).  

Although it has been suggested that leptin crosses the blood-brain barrier (BBB) via a specific transport system, we hypothesized the existence of a population of hypothalamic arcuate nucleus (ARC) neurons that senses leptin independently of this transport system.  

The three main sources of NPY innervation of the PVN are the hypothalamic arcuate nucleus and the noradrenergic and adrenergic neurons of the brainstem. By triple-labeling immunofluorescence detection of NPY, CRH, and agouti-related protein, a marker of NPY axons projecting from the arcuate nucleus, the noncatecholaminergic, NPY-ergic axon population was shown to arise primarily from the arcuate nucleus. We conclude that approximately two thirds of NPY-IR innervation to hypophysiotropic CRH neurons originates from catecholaminergic neurons of the brainstem, whereas the remaining one third arises from the arcuate nucleus. The catecholaminergic NPY innervation seems to modulate the activation of CRH neurons in association with glucoprivation and infection, whereas the NPY input from the arcuate nucleus may contribute to inhibition of CRH neurons during fasting..  

Leptin is a hormone that reduces food intake and increases energy expenditure by acting on the arcuate nucleus in the hypothalamus.  

The ER alpha were detected in all six major vestiblular nuclei which included arcuate nucleus (ARC) , paraventricularis nucleus (PVN) , periventricular nucleus (PeriV) , supraoptic nucleus (SON) , medial prioptic nucleus (MPN) and lateral hypothalamus area (LHA).  

Agrp expression in the brain is restricted to neurons in the arcuate nucleus of the hypothalamus and is elevated by states of negative energy balance.  

The arcuate nucleus (ARC) within hypothalamus is an important brain area that produces opioid peptides.  

Recent data have shown that in female mice, KiSS1 is positively regulated by estradiol (E(2)) in the anteroventral periventricular nucleus, an important reproductive neuroendocrine brain region, but negatively regulated in the arcuate nucleus.  

From the perspective of comparative morphology, the distribution of non-monoaminergic neurons in the common marmoset (Callithrix jacchus) was investigated using an immunohistochemical method with specific antibodies to tyrosine hydroxylase (TH) and aromatic-L-amino acid decarboxylase (AADC).TH-immunoreactive (IR) neurons (but not AADC-IR) neurons were observed in the olfactory tubercle, preoptic suprachiasmatic nucleus, periventricular hypothalamic nucleus, arcuate nucleus, paraventricular nucleus, periaqueductal gray matter, medial longitudinal fasciculus, substantia nigra, and nucleus solitaris.In contrast, AADC-IR (but not TH-IR), small, oval and spindle-shaped neurons were sparsely distributed in the following areas: the hypothalamus from the anterior nucleus to the lateral nucleus, the dorsomedial nucleus, the dorsomedial area of the medial mammillary nucleus and the arcuate nucleus; the midbrain, including the stria medullaris and substantia nigra; and the medulla oblongata, including the dorsal area of the nucleus solitaris and the medullary reticular nucleus.  

Expression of cFos after icv injection of NMS was observed in the supachiasmatic nucleus (SCN), arcuate nucleus, paraventricular nucleus (PVN), and supraoptic nucleus (SON).  

Meanwhile, the number of OFQ-immunoreactive neurons in the medial POA, ventromedial hypothalamus, and the arcuate nucleus on pro-estrus was significantly decreased compared to diestrus and estrus (P<0.05).  

Studies during the past 4 decades have shown this disinhibition to result from estrogen-induced synaptic plasticity (EISP), including a reversible approximately 50% loss in arcuate nucleus synapses.  

Double-labeling immunohistochemistry showed that irNEF cells were vasopressin or oxytocin positive in the paraventricular and supraoptic nucleus; cocaine-amphetamine-regulated transcript or tyrosine hydroxylase positive in arcuate nucleus; cocaine-amphetamine-regulated transcript or melanin concentrating hormone positive in the lateral hypothalamus.  

In contrast, SSTR3 is localized primarily in the paraventricular nucleus, dorsomedial hypothalamic nucleus, arcuate nucleus, and median eminence. SSTR4-like immunoreactivity is mainly confined to the arcuate nucleus, ventromedial hypothalamic nucleus, median eminence, and ependymal cells of third ventricle, with the rare SSTR4-positive neuron in the paraventricular nucleus.  

The arcuate nucleus (Arc) and the lateral hypothalamic area (LHA), two key hypothalamic nuclei regulating feeding behavior, express c-Fos, a marker of neuronal activation in fasted animals.  

Our understanding of the mechanisms promoting the formation of these critical circuits has been advanced significantly by recent evidence showing that neonatal leptin acts as a neurotrophic factor promoting the development of projections from the arcuate nucleus of the hypothalamus.  

Here, we report the photoperiodic regulation of the insulin receptor (IR) gene in the infundibular nucleus (anatomically homologous to the mammalian arcuate nucleus) of the Japanese quail.  

GLP-1 receptor mRNA is densely expressed in hypothalamic arcuate nucleus (ARC) and precisely overlaps the area occupied by proopiomelanocortin (POMC) neurons.  

We have previously shown that microinjection of galanin into the arcuate nucleus of hypothalamus (ARC) produced antinociceptive effects in rats (Sun et al., 2003a).  

Previously, 40% food restriction of male Siberian hamsters over 21 days in short-day (SD) photoperiod induced characteristic changes in expression of hypothalamic arcuate nucleus energy balance genes; mRNAs for neuropeptide Y, agouti-related peptide, and leptin receptor were upregulated, and those of proopiomelanocortin and cocaine- and amphetamine-regulated transcript were depressed.  

Based on these findings, we dissected the arcuate nucleus from ovariectomized guinea pigs treated with estradiol benzoate (EB) or vehicle and analyzed mRNA expression using quantitative real-time PCR. The effects of estrogen could be mediated by estrogen receptor-alpha, which we found to be highly expressed in the guinea pig arcuate nucleus and, in particular, proopiomelanocortin neurons.  

Several hypothalamic peptides that participate in the control of ingestive behavior are produced in neuronal cell bodies of the arcuate nucleus and/or the lateral hypothalamic area. The arcuate nucleus-median eminence area, a region with a weak blood-brain barrier, contains at least two neuronal cell populations that exert opposing actions on energy balance. The majority of the neurons located in the ventromedial aspect of the arcuate nucleus, which produce the orexigenic peptides neuropeptide Y (NPY) and agouti-related peptide (AGRP), contain in addition the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD) and the vesicular GABA transporter (VGAT), thereby supporting their GABAergic nature. Some neurons producing pro-opiomelanocortin (POMC)- and cocaine- and amphetamine-regulated transcript (CART), located in the ventrolateral division of the arcuate nucleus have recently been reported to contain the vesicular glutamate transporter 2 (VGLUT2), a marker for glutamatergic neurons, and the acetylcholine (ACh) synthesizing enzyme choline acetyltransferase (ChAT) as well as the vesicular ACh transporter (VAChT), supporting also a cholinergic phenotype.  

We assessed the possible link between endothelin receptor mediated phosphoinositide breakdown and NO/cGMP signaling pathways in rat arcuate nucleus-median eminence fragments (AN-ME), brain structures known to contain a rich plexus of nitric oxide synthase (NOS)-containing neurons and fibers, together with densely arranged endothelin ETB-receptors-like immunoreactive fibres.  

Leptin has been shown to increase PC1/3 and PC2 promoter activities, and starvation of rats, leading to low serum leptin levels, resulted in a decrease in PC1/3 and PC2 gene and protein expression in the paraventricular and arcuate nucleus of the hypothalamus.  

Within the brain, melanocortin-producing neurons originate in the arcuate nucleus of the hypothalamus (ARC) and the nucleus of the solitary tract (NTS) in the brainstem and project to various nuclei modulating energy balance.  

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