Nucleus Interpeduncularis

Sole expression of CRF and CRF-BP was apparent in the olfactory bulbs and superior raphe nucleus, respectively, whereas only UI was observed in the corpus mamillare, nucleus of the medial longitudinal fascicle, dorsal tegmental nucleus, nucleus lateralis valvulae, and Nucleus interpeduncularis.  

In the brainstem, 5-HT-ir perikarya appear within the superior and inferior raphe, the nucleus reticularis superioris, the Nucleus interpeduncularis and the inferior olive.  

The medial part of the substantia nigra pars reticulata, the Nucleus interpeduncularis, the area of the central gray, and the raphe complex displayed a high density of PE-11-like immunoreactivity.  

In addition, an increase in the deoxyglucose incorporation was specifically observed in the paleostriatum primitivum, rostral preoptic area, nucleus intercollicularis, Nucleus interpeduncularis and third nerve but a decrease was observed in the dorsomedial part of the hippocampus and in the nucleus nervi oculomotori in birds of the consummatory sexual behavior group by comparison with controls.  

An especially high density was observed in the bed nucleus of the stria terminalis, the central and cortical nuclei of the amygdala, the hypothalamus, the hippocampus, the raphe complex, the Nucleus interpeduncularis, the nucleus of the solitary tract, and laminae I and II of the spinal cord.  

High levels of binding were also detected in the bulbus olfactorius, bed nucleus commissuralis anterior, bed nucleus commissuralis pallii, nucleus accumbens, bed nucleus striae terminalis and Nucleus interpeduncularis.  

Prominent plexuses of cholinergic fibers were found in the olfactory bulb, pallium, basal telencephalon, ventral thalamus, tectum, and Nucleus interpeduncularis.  

A large population of positive neurons was observed in the substantia nigra, the ventral area of Tsai and the Nucleus interpeduncularis.  

In the mesencephalon and rhombencephalon, the distribution of immunoreactive fibers was heterogeneous, being most pronounced in a region between the nucleus nervi oculomotorii and the Nucleus interpeduncularis mesencephali, in the nucleus isthmi, and in the raphe region.  

Ten of the cell groups were situated within the region of the midline from the isthmic to the posterior rhombencephalic level and constituted the raphe system (nucleus annularis, decussatio brachium conjunctivum, area ventralis, external border of the Nucleus interpeduncularis, zona peri-nervus oculomotorius, zona perifasciculus longitudinalis medialis, zona inter-flm, nucleus linearis caudalis, nucleus raphe superior pars ventralis, nucleus raphe inferior).  

A marked increase of post-stimulation met-enkephalin immunoreactivity was observed in the tractus habenulo-penduncularis, tractus mamilo-thalamicus, and medial forebrain bundle, and a decrease at the level of the Nucleus interpeduncularis, medialis dorsalis, stria terminals, septalis lateralis, septalis medialis, accumbens septi, supraopticus, and amygdaloideus centralis.  

Long-range projections are comprised of ascending projections to the thalamus, habenula, preoptic area and dorsal telencephalon; and descending projections via the posterior tuberal nucleus, ventrally to the Nucleus interpeduncularis, and dorsally into the central gray.  

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 medial part of the substantia nigra pars reticulata, the Nucleus interpeduncularis, the area of the central gray, the raphe complex and the inferior olive displayed a high density of secretoneurin-like immunoreactivity.  

Most afferents appear to originate from the lobus subhippocampalis and neighboring area, whereas the only efferents found coursed in the fasciculus retroflexus to the neuropil of the Nucleus interpeduncularis.  

the lateral septum, the medial parts of the amygdala, some medial thalamic nuclei, the hypothalamus, habenula, Nucleus interpeduncularis, locus coeruleus, nucleus tractus solitarii, the substantiae gelatinosae of the caudal trigeminal nucleus and of the spinal cord.  

The highest binding levels of [ 125I]ANF were shown to occur in telencephalon areas, such as fasciculus diagonalis Brocae (232 fmol/mg protein), septum (194 fmol/mg protein) and olfactory bulb (153 fmol/mg protein), and in posterior sites, such as Nucleus interpeduncularis (177 fmol/mg protein), while lower levels (> 51 < 87 fmol/mg protein) were found in the hypothalamic sites of the diencephalon.  

Comparison of our results with the expression of neuronal nicotinic receptor subunits, as determined by in situ hybridization, suggests that many of the high affinity 3H-nicotine sites are localized presynaptically, as, for example, in the retinorecipient nuclei and the Nucleus interpeduncularis.  

Within the raphe nuclei, retrogradely fluorogold-labeled neurons were observed mainly in the median raphe nucleus (B8), groups B6/B5, and in the area lateral to the Nucleus interpeduncularis (group S4), but not in the dorsal raphe nucleus.  

The densest arborization of fibers in the mesencephalon was found in the stratum fibrosum et cellulare externum of the optic tectum, a major site of retinal projection, and in the Nucleus interpeduncularis mesencephali as well as in the oculomotor nuclei.  

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.  

The highest densities of specific ANF-binding were detected in the nucleus habenularis, thalamic regions, hypophyseal pars nervosa and Nucleus interpeduncularis.  

Anterograde transport showed the course of the fasciculus retroflexus, first dorsoventrally into the paramedian prerubral tegmentum and then longitudinally into the isthmic Nucleus interpeduncularis.  

In the latter region SST-14 immunoreactivity is concentrated in nerve tracts in the Nucleus interpeduncularis.  

A strong immunoreactivity was found in the perikarya, dendrites and axons of neurons located in the nucleus interstitialis commissurae anterioris, the nucleus medialis of the left habenula, the thalamus dorsalis, the thalamus ventralis, the nucleus lobi lateralis, the Nucleus interpeduncularis, the lobus vagi and the medial reticular zone.  

Serotonin perikarya were found in the caudal midbrain tegmentum, in the lateral part of the nucleus reticularis isthmi, the lateral part of the Nucleus interpeduncularis and along the midline in the raphe superior. Prominent concentrations were found in the dorsal cortex, lateral septum, lateral geniculate nucleus, median eminence, pretectal nucleus, Nucleus interpeduncularis, vestibular nucleus and olivary complex.  

High densities were observed in caudate-putamen, nucleus basalis accesorius of the amygdala, hippocampal gyrus dentatus and CA3 field, locus niger, Nucleus interpeduncularis and motor trigeminal and facial nuclei.  

The diencephalon, the periventricular preoptic area, the supraoptic nucleus, and, in particular, the medial habenular nucleus are densely innervated by NAi fibers, whereas in the midbrain NAi plexuses are found in the ventral tegmental area, the substantia nigra and its dorsolateral extension (RA8), and in an area ventral to the Nucleus interpeduncularis, pars ventralis.  

Although the distribution pattern of somatostatin immunoreactivity was basically the same between the two animals, several regions, especially the nucleus anterior hypothalami and the Nucleus interpeduncularis, were found to contain large aggregates of somatostatin-immunoreactive neurons in the mouse brain but not in the rat.  

In the tegmentum, cell bodies were labelled in the nucleus mesencephalicus profundus, pars ventralis, while the Nucleus interpeduncularis had dense cholinergic innervation.  

Densely packed immunoreactive fibers were widely distributed in the substantia nigra, Nucleus interpeduncularis, nucleus raphes, superior colliculus, periaqueductal central gray, nucleus parabrachialis lateralis and medialis, locus coeruleus, trapezoid body, nuclei cochleares, nucleus spinalis nervi trigemini, tractus spinalis nervi trigemini, nucleus tractus solitarii, nucleus dorsalis nervi vagi, nucleus gracilis, nucleus cuneatus, nucleus cuneatus accessorius, and in the reticular formation throughout the lower brainstem.  

Other structures presenting high levels of binding were the substantia nigra, Nucleus interpeduncularis, locus coeruleus, nucleus nervi hypoglossi, nucleus nervi facialis, mammillary bodies and other parts of the hypothalamus.  

Other than the raphe system, serotonin-immunoreactive perikarya were seen in the following regions: the reticular formation (18.9%), the lemniscus medialis (8.5%), the Nucleus interpeduncularis (1.5%), the subpyramidal region (4.0%) and the periaqueductal gray (0.2%)..  

The changes induced by nerve growth factor (NGF) and by GM1-ganglioside administration on serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and tryptophan content and on choline acetyltransferase activity, were studied in the central nervous system of rats undergoing electrolytic damage of a mesencephalic area, located near the Nucleus interpeduncularis.  

In other sites (nuclei lateralis, ventromedialis and posterior hypothalami, nucleus septi lateralis, Nucleus interpeduncularis and substantia grisea periventricularis) the effect was lower, and most of these sites showed different sensitivity to the three tachykinins. These results show that: (1) the antidipsogenic effect of tachykinins can be elicited not only in forebrain, but also in midbrain structures such as the substantia grisea periventricularis and the Nucleus interpeduncularis; (2) the distribution of brain sites sensitive to the antidipsogenic effect of substance P and physalaemin is always overlapping, while this is not true for eledoisin.  

In the mesencephalon and rhombencephalon, sparse staining was observed in the central gray, torus semicircularis, Nucleus interpeduncularis, raphe, reticular formation, Purkinje and granular cell layers in the cerebellum, and nucleus cerebellaris medialis.  

Grains were less dense in the hypothalamus lateralis, in the substantia nigra and in the Nucleus interpeduncularis.  

The endopeptidase was mapped in cryostat sections of the fore and mid-brain to the following structures: caudate-putamen, globus pallidus, olfactory tubercle, Nucleus interpeduncularis and substantia nigra.  

5,7-Dihydroxytryptamine (5,7-DHT) injections in the ventromedial tegmentum (VMT) at the level of Nucleus interpeduncularis or in the ventral raphe area (VR) of the medulla oblongata were used to study the separate roles of forebrain and spinal 5-HT in the antinociceptive effect of morphine in rats.  

SRIF fibers were found throughout most of the brain predominating within the nucleus praeopticus, pars ventralis hypothalami, and the Nucleus interpeduncularis.  

A few labeled cells also occur in the Nucleus interpeduncularis, nucleus raphes superior, and lateral reticular formation.  

5-HT cell bodies were found predominantly in the raphe region including the nucleus raphe dorsalis and raphe medianus, Nucleus interpeduncularis, reticular formation and dorsal area of the medial lemniscus..  

In the brain stem a dense serotonergic innervation was observed in all of the motor nuclei of the cranial nerves, in two layers of the tectum mesencephali, in the Nucleus interpeduncularis pars ventralis, the nucleus profundus mesencephali pars rostralis, the periventricular grey, the nucleus parabrachialis, the vestibular nuclear complex, the nucleus descendens nervi trigemini, the nucleus raphes inferior, and parts of the nucleus tractus solitarii.  

The lesions resulted in significant decreases of choline acetyltransferase in the habenula (-34%) and in the Nucleus interpeduncularis (-36%), thus demonstrating the existence of a major cholinergic projection to these nuclei from the supracommissural septum.  

The results of this study of the distribution of enkephalin-like immunoreactivity in four human "senile" and "presenile" brains by immunofluorescence microscopy (Coons' Method) showed specifically fluorescing varicosities containing fibres in the following areas: nucleus accumbens, nucleus caudatus, pallidum (mainly the external segment), septal nuclei, substantia innominata, hypothalamus, hypophysis, substantia nigra, Nucleus interpeduncularis, locus coeruleus and other nuclei of the brain stem, most of the nuclei of the cranial nerves (mainly the sensitive) and spinal cord (mainly the substantia gelatinosa of the posterior horn).  

The distribution of MChR was heterogeneous, with highest densities in the striatum and nucleus accumbens and lowest in the globus pallidus, Nucleus interpeduncularis and nucleus septi.  

The greatest concentrations of these fibers were in the nucleus medialis septi, lateral portion of striatum, nucleus corporis geniculi, nucleus entopeduncularis, periventricular gray of ventral hypothalamus, optic tectum, nucleus isthmi, Nucleus interpeduncularis, dorsal edge of medulla oblongata, and fasciculus solitarius..  

The forebrain cholinergic and GABAergic projections to the habenula and Nucleus interpeduncularis have been investigated by means of surgical and kainic acid lesions. Bilateral transection of the stria medullaris caused a 50% decrease of choline acetyltransferase in both the habenula and Nucleus interpeduncularis, and a 65% decrease of glutamate decarboxylase in the habenula. Electrolytic lesions of the posterior septum (nucleus triangularis septi and nucleus septo-fimbrialis) accounted for at least 30-40% decrease of the cholinergic parameter in the habenula and Nucleus interpeduncularis. Kainic acid injections causing very large neuronal destruction in the nucleus of the diagonal band of Broca, and more than 70% decrease of choline acetyltransferase in the dorsal hippocampus, did not affect the cholinergic parameter in either the medial or lateral habenula or Nucleus interpeduncularis. The present study points at the nuclei of the posterior septum as the source of a major cholinergic projection to the habenula and Nucleus interpeduncularis, and reveals a previously unsuspected GABAergic input from the nucleus of the diagonal band to the medial habenula..  

Labeled areas were the Nucleus interpeduncularis, periaqueductal gray matter, locus coeruleus and nucleus tractus solitarius.  

A withdrawal syndrome was precipitated by naloxone in morphine-dependent rats injected with 5,7-dihydroxytryptamine (5,7-DHT) in the ventromedial tegmentum (VMT) at the level of the Nucleus interpeduncularis.  

Afferents to the habenula have been demonstrated from the septal area, nucleus entopeduncularis anterior, triangular area, nucleus periventricularis hypothalami, Nucleus interpeduncularis, nucleus raphes superior, locus coeruleus, nucleus isthmi, nucleus dorsalis motorius nervi vagi, and the mesencephalic tegmentum.  

A considerable number of IA cells (13,600, representing 23% of the total) were found in locations outside the raphe nuclei: in ventral brainstem as lateral extensions from the raphe, among the bundles of fasciculus longitudinalis medialis, in periventricular gray and adjacent tegmentum, mixing with the noradrenergic cells of the locus coeruleus complex, among the mesencephalic dopamine cells, and in the Nucleus interpeduncularis..  

Moreover, a preliminary study shows that, in the lenniscus medialis, nucleus interpreduncularis paramedialis and pontine nuclei, more than 50% of the labelled, presumably serotonergic cells are in direct contact with blood vessels, while in the raphe dorsalis and Nucleus interpeduncularis dorsalis the percentage is only 20 to 25%.  

In addition, this immunohistochemical technique revealed serotonin-containing perikarya in the following regions: 1) the periaqueductal gray, especially lateral to the nucleus raphe dorsalis, 2) the Nucleus interpeduncularis, 3) the nucleus parabrachialis ventralis and dorsalis, 4) the field of the lemniscus lateralis, and 5) the reticular formation of the pons and medulla oblongata.  

Lastly, some-sulf positive galCb-negative processes, as yet unidentified, were also found in the periaqueductal gray matter and in the Nucleus interpeduncularis..  

The activities of five enzymes involved in acetyl-CoA synthesis, pyruvate dehydrogenase complex, ATP citrate lyase, carnitine acetyltransferase, acetyl-CoA synthetase, and citrate synthase, were determined in normal Nucleus interpeduncularis and Nucleus interpeduncularis in which cholinergic terminals were removed following lesion of the habenulointerpeduncular tract. In normal Nucleus interpeduncularis the activities of carnitine acetyltransferase and pyruvate dehydrogenase complex were higher than the activity of ChAT (choline acetyltransferase), whereas the activities of acetyl-CoA synthetase and citrate synthase were considerably lower than that of ChAT.  

The regions of localization for enkephalin fibers and terminals include in the forebrain: lateral septum, central nucleus of the amygdala, area CA2 of the hippocampus, certain regions of the cortex, corpus striatum, bed nucleus of the stria terminalis, hypothalamus including median eminence, thalamus and subthalamus; in the midbrain: Nucleus interpeduncularis, periaqueductal gray and reticular formation; in the hind brain: nucleus parabrachialis, locus ceruleus, nuclei raphes, nucleus cochlearis, nucleus tractus solitarii, nucleus spinalis nervi trigemini, motor nuclei of certain cranial nerves, nucleus commissuralis and formatio reticularis; and in the spinal cord the substantia gelatinosa.  

Substance P-reactive neuron cell bodies were present in spinal root ganglia, nucleus habenulae medialis, Nucleus interpeduncularis, caudoputamen and globus pallidus.  

In contrast to these early monoamine fluorescing groups, catecholamine-containing neurons are not routinely detectable in the Nucleus interpeduncularis until six months of age. All catecholamine-containing neuronal groups, with the exception of those located in the midbrain region (Nucleus interpeduncularis, reticular zone) have fluorescent processes that contact the cerebrospinal fluid (CSF).  

Most PrV axons project ventromedially from PrV through the ventral pontine tegmentum and gradually decussate across the midline in the mesencephalic tegmentum up to the level of the caudal pole of Nucleus interpeduncularis.  

The records were made by means of telemetry from lateral hypothalamus, nucleus ruber, formatio reticularis, dorsal hippocampus and the ventral mesencephalic tegmentum (VMT) surrounding the Nucleus interpeduncularis.  

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