Immunoreactive somata formed a single group in the hypothalamus, but were distributed beyond several nuclei, namely, the ventral aspect of the nucleus preopticus posterior, dorsal aspect of the Nucleus Suprachiasmaticus and anterior aspect of the pars ventralis hypothalami. 
Photostimulation increased c-fos mRNA expression in the pineal gland, Nucleus Suprachiasmaticus, pars visualis (vSCN) and nucleus inferioris hypothalami compared to that of their corresponding nonphotostimulated controls.
The synchronization of all these peripheral rhythms is controlled by a superordinate "master-clock", which is located in the Nucleus Suprachiasmaticus of the hypothalamus.
Additional afferents reach the inferior lobe from the nucleus glomerulosus, Nucleus Suprachiasmaticus, dorsal and central posterior thalamic nucleus, nucleus lateralis valvulae, magnocellular part of the magnocellular nucleus of the preoptic region, caudal nucleus of the preglomerular region, posterior tuberal nucleus, area dorsalis of the telencephalon, and a tegmental nucleus (T2).
In these two species, each tracer revealed contralateral retinal projections to three hypothalamic regions (subventricular gray matter, Nucleus Suprachiasmaticus, and area optica hypothalami lateralis), five thalamic regions (nuclei ovalis, dorsolateralis anterior, ventrolateralis and ventrobasalis, and lateral geniculate complex, of which six subcomponents can be distinguished), six pretectal regions (nuclei posterodorsalis, lentiformis mesencephali, griseus tectalis, geniculatus pretectalis, area optica commissurae posterior and area optica pretectalis lateroventralis), six outermost layers of the optic tectum, and the nucleus opticus tegmenti.
Immunohistochemistry for c-fos expression in the Nucleus Suprachiasmaticus at different circadian times showed that c-fos was induced only in animals exposed to a 1-h light pulse during the subjective night, but not during the subjective day or in control animals in the absence of a light pulse.
Very high levels of binding were detected in various preoptic/hypothalamic sites including the Nucleus Suprachiasmaticus pars medialis, nucleus anterior medialis hypothalami, nucleus infundibularis, nucleus mammillaris medialis, nucleus posteromediale hypothalami and nucleus hypothalami ventromedialis. This latter difference was confirmed in the one point assays that also identified higher levels of specific binding in the Nucleus Suprachiasmaticus pars medialis of males as compared with females.
It is speculated that high daytime levels of aMT6s under long-day photoperiods in non-responders result in down-regulation of melatonin receptors of the Nucleus Suprachiasmaticus, the pacemaker for the pineal gland, leading to a lack of response to the transition to short-day photoperiods..
A weaker signal was detected in the nucleus anterioris periventricularis, Nucleus Suprachiasmaticus and thalamic region.
We karyometrically investigated the Nucleus Suprachiasmaticus (SCN) which had been manipulated in several ways in order to analyze the functional importance of the pineal gland on the primary pacemaker of mammals in the course of the year.
Staining of the nucleus periventricularis was found to be moderate, whereas no labelling of perikarya in the nucleus arcuatus, the preoptic area and the Nucleus Suprachiasmaticus was detectable.
No IMEL binding could be demonstrated in the pineal gland, the hippocampus, the Nucleus Suprachiasmaticus, the visual wulst or the pituitary..
A high or moderate density of perikarya and a high density of fibers containing parvalbumin was observed in the nuclei lateralis posterior, lateralis dorsalis, pulvinar, corpus geniculatum laterale, reticularis, medialis dorsalis, centrum medianum, subparafascicularis, ventralis postero-medialis, ventralis postero-lateralis, habenularis medialis, parafascicularis, corpus geniculatum mediale, centralis lateralis, rhomboidens, reuniens, centralis medialis, ventralis medialis, ventralis lateralis, parataenialis, anterior ventralis, anterior medialis, ventralis anterior, hypothalamus posterior, corpus mamillare, area hypothalamica dorsalis, and in the Nucleus Suprachiasmaticus.
In all species, contralateral visual projections exist to 15 targets: two hypothalamic structures (Nucleus Suprachiasmaticus and n.
For alpha 8-like immunoreactivity, slight reduction of neuropil staining could be observed in the ventral geniculate complex, griseum tecti, nucleus lateralis anterior, nucleus lentiformis mesencephali, layers 4 and 7 of the tectum, and Nucleus Suprachiasmaticus.
Immunoreactive nerve fibers were present in all regions containing labeled perikarya and in 1) telencephalon: septum, nucleus fasciculi diagonalis Brocae; 2) diencephalon: nucleus paraventricularis, nucleus supraopticus, Nucleus Suprachiasmaticus, subventricular grey, nucleus of the paraventricular organ, nucleus mamillaris, infundibular decussation, outer layer of the median eminence, posterior commissure and subcommissural organ region, habenula, nuclei dorsomedialis anterior, and dorsolateralis anterior of the thalamus; and 3) mesencephalon and rhombencephalon: stratum griseum periventriculare, stratum fibrosum periventriculare, laminar nucleus of the torus semicircularis, periventricular grey, nucleus interpeduncularis, nucleus ruber, substantia nigra, locus coeruleus, raphe nuclei, nuclei of the reticular formation, nucleus motorius nervi trigemini, cochlear and vestibular area, and nucleus spinalis nerve trigemini.
The retinal fibers decussate completely in alternating fascicles at the optic chiasma and course to terminate in two hypothalamic nuclei (Nucleus Suprachiasmaticus and nucleus opticus periventricularis hypothalami posterior), six thalamic nuclei (nucleus ovalis, nucleus geniculatus lateralis dorsalis partes lateralis and medialis, nucleus geniculatus lateralis ventralis, lateral part of nucleus dorsolateralis anterior, and nucleus ventrobasalis), four pretectal nuclei (nucleus griseus tectalis, nucleus lentiformis mesencephali, nucleus geniculatus pretectalis and nucleus posterodorsalis), the optic tectum (stratum griseum et fibrosum superficiale) and the tegmental nucleus opticus tegmenti.
In the diencephalon, a dense accumulation of FMRFamide-immunoreactive neurons was observed in the area preoptica lateralis, the Nucleus Suprachiasmaticus, the nucleus periventricularis hypothalami, the area lateralis hypothalami, and the dorsal region of the nucleus geniculatus lateralis.
The non-CAnergic brain regions that represented CAT-stained cells were further divided into two groups: (i) regions containing AADC-labeled cells, for example, bed nucleus of the stria terminalis, Nucleus Suprachiasmaticus, mammillary body, nucleus raphe dorsalis, inferior colliculus, and nucleus parabrachialis, and (ii) regions containing no AADC-positive cells, for example, main olfactory bulb (except A16), accessory olfactory bulb, nucleus olfactorius anterior, caudoputamen, septum, nucleus accumbens, hippocampus, medial nucleus of the amygdala, entorhinal cortex, nucleus supraopticus, and parasubiculum.
The change in the night/day distribution of food intake might be due to age-related changes in the Nucleus Suprachiasmaticus of the hypothalamus..
High numbers of beta 2-LI somata were found only in the nucleus spiriformis lateralis, whereas neuropil staining for beta 2-LI was intense in the nucleus geniculatus lateralis ventralis, Nucleus Suprachiasmaticus, nucleus lateralis anterior, nucleus habenularis lateralis, area pretectalis, griseum tecti, nucleus lentiformis mesencephalis, nucleus externus, and nucleus interpeduncularis, and in the stratum griseum centrale, stratum griseum et fibrosum superficiale, and stratum opticum of the tectum.
In the preoptic area, FMRFamide-containing perikarya were restricted to the lateral preoptic area, paraventricular subdivision of the nucleus preopticus, Nucleus Suprachiasmaticus and nucleus preopticus periventricularis posterior.
High levels of CAT were also localized in other regions: e.g., hippocampus pars posterior, nucleus preopticus, nucleus anterior hypothalami, nucleus interstitialis striae terminalis, Nucleus Suprachiasmaticus and nucleus accumbens septi.
The rate of accumulation of 5-hydroxytryptophan after decarboxylase inhibition was reduced in the PVN, nucleus supraopticus, nucleus periventricularis and Nucleus Suprachiasmaticus of the obese rats.
In reptiles retinofugal fibres innervate hypothalamic neuronal populations called either Nucleus Suprachiasmaticus or Nucleus praeopticus. Some former but also newer methods of research (Stumpf and Sar, 1975) also depicted optic fibers which terminate in hypothalamic sites apart from the Nucleus Suprachiasmaticus and the area hypothalamica anterior (Conrad and Stumpf, 1975).
The perikarya of the Nucleus Suprachiasmaticus, nucleus hypothalamicus ventromedialis and nucleus arcuatus showed light staining.
As specific melatonin receptors have been identified in the human Nucleus Suprachiasmaticus, which is the "master" circadian pacemaker, the observed phenomenon might be mediated through this structure.
In regio supraoptica there are nucleus paraventricularis, nucleus supraopticus, area hypothalamica anterior and Nucleus Suprachiasmaticus.
The Cytoplasmic RNA content in neurons of the Nucleus Suprachiasmaticus was determined cytophotometrically in adult mice following injection of kainic acid.
Within the diencephalon and particularly in the hypothalamus, i.e., in the nucleus preopticus, Nucleus Suprachiasmaticus, the paraventricular organ, lateral hypothalamic area, recessus mamillaris, and nucleus tuberculi posterioris, numerous cell somata stain for dopamine.
Electrolytic lesions of the Nucleus Suprachiasmaticus caused disappearance of the circadian variation of insulin and glucose responses. It is suggested that the Nucleus Suprachiasmaticus directly or indirectly controls vagal activity, which determines via its influence on the gastrointestinal tract the circadian variation in blood glucose and plasma insulin responses after food intake..
The periventricular hypothalamus and the paraventricular organ, the pineal organ, and (possibly) the Nucleus Suprachiasmaticus also contained ChAT-IR neurons.
These were particularly pronounced in the caudoputamen (+47%), nucleus ventralis thalami (+32%), nucleus ventromedialis hypothalami (+57%) and the Nucleus Suprachiasmaticus (+39%), while the nucleus ambiguus, nucleus dorsalis nervi vagi, nucleus cuneatus and nucleus loci coeruleus also showed increases in DOG utilisation of between 23% and 29%.
Only the anterior and medial parvocellular parts of the nucleus paraventricularis and the Nucleus Suprachiasmaticus contained numerous cell bodies which exhibited BN/ GRP -LI.
However, the Nucleus Suprachiasmaticus, where numerous serotoninergic fibers have been reported to occur in the rat, appeared to be almost devoid of these fibers.
Twenty-four hour rhythms, at 4 h intervals, of norepinephrine (NE) and serotonin (5-HT) contents were investigated in the rat brain regions where sleep-wakefulness regulation is believed to occur: Nucleus Suprachiasmaticus (SC), n.
The results showed that each eye in this animal projects not only to the contralateral side of the brain but also to several ipsilateral visual centers including the Nucleus Suprachiasmaticus, ventrolateral nucleus of the optic tract and the optic tectum.
In vivo rates of 5-hydroxytryptophan accumulation (following administration of the decarboxylase inhibitor R04/4602/1) and levels of 5-HT in the nucleus raphe dorsalis (DR), nucleus centralis superior (NCS), nucleus septalis lateralis (LS), Nucleus Suprachiasmaticus (SCN), nucleus hypothalamicus anterior (AH), and nucleus amygdaloideus centralis (AG) were determined following administration of fluoxetine, 5-methoxy-N,N-dimethyltryptamine, methiothepin, L-tryptophan and reserpine.
There was a heavy concentration of serotonin nerve fibers in the Nucleus Suprachiasmaticus, the nucleus ventromedialis and the nucleus dorsomedialis.
Significant concentrations of serotonin were evident in most areas, although the levels of this neurotransmitter were much lower in the median eminence region and Nucleus Suprachiasmaticus than in the rat.
Estrogen treatment reduced the concentrations of dopamine in the nucleus accumbens septi, striatum, median eminence, nucleus anterior hypothalami, Nucleus Suprachiasmaticus, nucleus arcuate IV-V, area ventralis tegmenti, interpeduncular nucleus and nucleus interstitialis striae terminalis.
Particularly dense plexus of the fibers and terminals have been observed in the lateral hypothalamic area, nucleus mamillaris medialis, the nucleus perifornicalis, the Nucleus Suprachiasmaticus and the nucleus ventromedialis hypothalami.
The identification of serotonergic input to the rat median eminence and Nucleus Suprachiasmaticus was carried out by fluorescence and electron microscopy.
In the 5 species the retinal ganglion cells project to the contralateral hypothalamus (Nucleus Suprachiasmaticus), thalamus (nucleus geniculatus lateralis pars ventralis, nucleus geniculatus lateralis pars dorsalis), pretectum (nuclei lentiformis mesencephali, geniculatus pretectalis, postero-dorsalis griseus tectalis), tectum opticum (layer 2 to layer 6 of the stratum griseum et fibrosum superficiale) and tegmentum mesencephali (nucleus opticus tegmenti).
In eyeless animals, a portion of the mediobasal hypothalamus and one of its constituent nuclear pairs, Nucleus Suprachiasmaticus (SCN), were markedly abnormal in the embryo and adult.
Changes in the activity of monoamine oxidase (MAO) and acetylcholinesterase (AChE) following unilateral eye enucleation were measured for the superior colliculus (SC), lateral geniculate body (LGB), and Nucleus Suprachiasmaticus (NSC) in the rat by means of microspectrophotometry.
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