Inhibitory effects of neuropeptide Y on cyclic AMP accumulation in slices of the nucleus tractus solitarius region of the rat

The effects of neuropeptide Y (NPY) on cyclic AMP (cAMP) accumulation in slices of the dorsal midline area of the caudal part of the medulla oblongata containing the nucleus tractus solitarius (nTS) have been studied. Neuropeptide Y (30 and 300 nM) significantly reduced the [3H]cAMP accumulation induced by forskolin and phorboldibutyrate. Similar results were obtained after incubation with the alpha-adrenoceptor agonist clonidine (1 microM). These results indicate that stimulation of the NPY receptors and alpha-adrenoceptors in the nTS region may cause inhibition of the adenylate cyclase. Such a mechanism may at least partly underlie the centrally mediated hypotensive effects of the costored transmitters adrenaline and NPY.     

Chronic imipramine treatment reduces (+)2-[125I]iodolysergic acid, diethylamide but not 125I-neuropeptide Y binding in layer IV of rat cerebral cortex

The effects of chronic oral (2 X 10 mumol/kg, twice daily for 14 days) imipramine treatment on (+)2-[125I]-iodolysergic acid, diethylamide (125I-LSD) and 125I-neuropeptide Y (125I-NPY) receptor binding were examined in rat cerebral cortex by quantitative receptor autoradiography. A 35% reduction of 125I-LSD binding was observed in layer IV, both in the frontal and occipital cortex, while there was no significant change in 125I-NPY binding. The observed decrease in 125I-LSD binding is probably due to a reduction in the density of 5-hydroxytryptamine (5-HT) receptors of the 5-HT2 type. This reduction may represent a disturbance in the 5-HT synapses, regulating the transmission of the specific afferents innervating layer IV of the cerebral cortex.     

Autoradiographic localization of substance P receptors in rat medulla: effect of vagotomy and nodose ganglionectomy

Light microscopic autoradiography of [125I]Bolton-Hunter substance P binding sites was used to study the localization and denervation-induced changes in substance P receptors in the medulla oblongata. Substance P binding sites were widely distributed. The highest density was in the rostral nucleus ambiguus, dorsal motor nucleus of the vagus, nucleus of the solitary tract, hypoglossal nucleus, spinal trigeminal nucleus and inferior olive. Moderate density was apparent in the commissural nucleus of the solitary tract, area postrema, parvocellular reticular nucleus, medial vestibular nucleus and facial nucleus. The remainder of the medullary nuclei contained few or no specific substance P binding sites. Specific binding was inhibited by the addition of unlabeled substance P (1 microM). The association of substance P binding sites with the spinal trigeminal nucleus and with several nuclei involved in autonomic function suggest a role for substance P receptor activation in nociceptive and autonomic regulation, respectively. To study the influence of afferent and efferent denervation, the substance P binding sites in the medulla of sham operated rats were compared with those of both unilateral nodose ganglionectomized and cervical vagotomized rats. Substance P binding was unilaterally reduced in the rostral nucleus ambiguus and the rostral dorsal motor nucleus of the vagus with either surgical procedure. No changes in substance P binding were detected in other medullary nuclei, including the nucleus of the solitary tract, the site of termination of afferent vagal fibers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increased neuropeptide Y (NPY) receptor binding in hippocampus and cortex of spontaneous hypertensive (SH) rats compared to normotensive (WKY) rats

Specific 125I-NPY binding in various brain regions of spontaneous hypertensive (SH) rats and age-matched normotensive (WKY) rats was compared. SH rats exhibited significantly greater 125I-NPY binding than WKY rats in the hippocampus (43%) and cortex (18%), but not hypothalamus, midbrain, striatum or pons-medulla. Scatchard analysis indicated that the increased 125I-NPY binding in the hippocampus of SH rats represents a greater number of NPY binding sites.     

Autoradiographic localization of receptors for neuropeptide Y (NPY) in the brain of broiler and leghorn chickens (Gallus domesticus)

Broiler and leghorn chickens show an extreme difference in ingestive and reproductive behavior. As neuropeptide Y (NPY) influences both behaviors the goal of this study was to elucidate the distribution, expression and affinity of NPY binding sites in broiler and leghorn chicken brain. By means of in vitro autoradiography, sections of chicken brains were incubated with ³H-NPY as tracer and NPY as displacer. Scatchard analysis revealed a curvilinear plot suggesting two subtypes of the NPY binding site in the chicken brain, a high affinity one (K_D = 2–4 nM) and one with a lower affinity (K_D = 18–24 nM). Binding sites for NPY are localized with high density in the different subdivisions of the neostriatum and the hyperstriatum, the cerebellum, the nucleus septalis lateralis and medialis, the nucleus ruber and the nucleus tractus solitarii. A lower density of NPY binding sites was found in the different subdivisions of the striatum, the nucleus mesencephalicus lateralis pars dorsalis, the paleostriatum, the archistriatum intermedium pars ventralis, the nucleus geniculatus lateralis, the nucleus taeniae, the locus ceruleus, the nucleus rotondus, the nucleus habenularis medialis, the nucleus dorsomedialis anterior (rostralis) thalami, the pituitary and the area of the hypothalamus with its nuclei such as the nucleus paraventricularis magnocellularis and the nucleus preopticus medialis. Comparison of the localization of NPY binding sites in the brains of broilers and leghorns showed no differences but the density of both receptor types is two to three times higher in broilers than in leghorns.     

Neurotensin receptors in the human amygdaloid complex. Topographical and quantitative autoradiographic study

The distribution of high affinity ¹²⁵I-neurotensin (NT) binding sites were investigated in the amygdaloid complex of adult humans by means of dry film and emulsion autoradiography. Autoradiograms were analysed quantitatively using [¹²⁵I] standards and an image analyser system, and data obtained were converted to nCi of ligand bound per mg tissue. High densities of ¹²⁵I-NT binding sites were found in the following amygdaloid structures: the dorsal part of the accessory basal nucleus, the medial part of the cortical nucleus, the lateral subdivision of the central nucleus, the paralaminar nucleus, the amygdalohippocampal transition area and the rostral portions of the anterior amygdaloid area. The ventral part of the accessory basal nucleus, the intercalated cell groups and the remaining parts of the anterior amygdaloid area showed moderate density of NT binding sites, while the medial, basal and lateral amygdaloid nuclei, the lateral part of the cortical nucleus, the medial subdivision of the central nucleus, as well basal and lateral amygdaloid nuclei, the lateral part of the cortical nucleus, the medial subdivision of the central nucleus, as well as the corticoamygdaloid transition area exhibited low densities of ¹²⁵I-NT binding sites. At microscopic level, silver grains appeared more or less evenly distributed over both neuronal perikarya and the surrounding neuropil. In comparison to NT-immunoreactivity, NT receptors showed mismatching distribution throughout most parts of the amygdala, with the exception of the lateral subdivision of the central nucleus, where NT-immunoreactive perikarya and nerve fibers as well as ¹²⁵I-NT binding sites were found in high density.     

Distribution and pharmacological characterization of somatostatin receptor binding sites in the sheep brain

Somatostatin binding sites have been localized and quantified in the sheep brain using ¹²⁵I-Tyr₀-DTrp₈-somatostatin, by quantitative high resolution light microscopic autoradiography. Sections were analyzed by densitometry on radioautographic film, and subsequently on slides coated with photoemulsion. Specific somatostatin binding sites were concentrated in the medial habenula, superior colliculus, dorsal motor nucleus of the vagus nerve, inferior olive, spinal trigeminal nucleus, and cerebellum. In competition experiments, octreotide, a sst2/sst3/sst5 selective agonist only partially displaced ¹²⁵I-Tyr₀-DTrp₈-somatostatin in the three cerebellar layers while it was fully active as compared to somatostatin 14 and 28 in the deeper layers of the parietal cortex. Moderate to low somatostatin receptor densities were present in the mesencephalic periaqueductal gray, dorsal raphe, thalamic paraventricular nucleus, interpeduncular nucleus, pineal gland, dorsal tegmental, dorsolateral tegmental and parabrachial nuclei, nucleus of the solitary tract. The distribution of somatostatin binding sites generally correlates with the data obtained on slides dipped in photoemulsion which provided better resolution and more precise localization. In most of the labeled areas, ¹²⁵I-Tyr₀-DTrp₈-somatostatin receptor binding was distributed between both neuropil and perikarya. Perikarya bearing ¹²⁵I-Tyr₀-DTrp₈-somatostatin receptors were observed in areas which did not display detectable binding sites on film such as the preoptic-anterior hypothalamic complex and arcuate nucleus and in the locus coeruleus. In conclusion, the distribution of ¹²⁵I-Tyr₀-DTrp₈-somatostatin binding sites in sheep brain is very reminiscent of other mammals being closer to the human than to rodents.     

Distribution of neuropeptide Y receptors in the rat hippocampal region

The distribution of binding sites for neuropeptide Y (NPY) was studied in the rat hippocampal region by using [3H]NPY together with quantitative in vitro receptor autoradiography. The highest density of specifically bound [3H]NPY was found in regio superior and regio inferior of Ammon's horn. Within these fields, stratum oriens, stratum pyramidale and stratum radiatum harboured the highest densities of [3H]NPY binding while stratum moleculare was relatively poor in [3H]NPY binding sites. In area dentata, the highest density of [3H]NPY binding was found in the inner one third of the molecular layer. In the presubiculum and in the entorhinal area, the outer two layers were slightly more enriched in [3H]NPY binding sites than were the deep layers. In all hippocampal subfields a clear gradient of increased [3H]NPY binding was found at successively more ventral levels.     

Up-regulation of 5-hydroxytryptamine2 and neurokinin-1 receptors associated with serotonin/substance P hyperinnervation in the rat inferior olive.

The fate of serotonin and substance P receptors following serotonin/substance P hyperinnervation of CNS tissue was investigated in the inferior olivary complex of adult rats subjected to earlier intraventricular administration of 5,6-dihydroxytryptamine. [3H]8-hydroxy-2-(Dl-n-propylamino)tetralin, [3H]5-hydroxytryptamine, [3H]ketanserin and [125I]Bolton-Hunter-substance P were respectively used to label 5-hydroxytryptamine1A, 5-hydroxytryptamine1B, 5-hydroxytryptamine2 and neurokinin-1 receptor sites for quantitative ligand binding autoradiography. Only 5-hydroxytryptamine2 and neurokinin-1 sites were detected in the normal or serotonin/substance P-hyperinnervated inferior olivary complex. In the normal inferior olivary complex, the density of [3H]ketanserin binding (5-hydroxytryptamine2 receptors) was relatively low, being the highest in pars a of the caudal medial accessory olive and the principal olive; moderate in pars c of the caudal medial accessory olive; truly low in the medial and the lateral dorsal accessory olive, nucleus b and pars b of the caudal medial accessory olive; and negligible in the middle medial accessory olive, rostral medial accessory olive and the smaller subnuclei. [125I]Bolton-Hunter-substance P binding (neurokinin-1 receptors) appeared denser, being highest in nucleus beta and the middle medial dorsal accessory olive; moderate in the three portions of the caudal medial accessory olive, the lateral dorsal accessory olive and the dorsal cap of Kooy; low in the rostral medial accessory olive, the ventrolateral outgrowth and the dorsomedial cell column; and very low or null in the principal olive and the medial dorsal accessory olive. After serotonin/substance P hyperinnervation, there were striking increases in the apparent density of both populations of receptor. [3H]Ketanserin binding was now stronger in the most olivary subnuclei, including some in which it had not been found in the normal, such as the middle and the rostral medial accessory olive. [125I]Bolton-Hunter-substance P binding showed even greater elevations in a few subnuclei, such as the principal olive and the dorsomedial cell column; it was now detectable in the medial dorsal accessory olive, unchanged in the dorsal cap of Kooy and the ventrolateral outgrowth, and slightly decreased in the lateral dorsal accessory olive. The normal and altered distributions of both ligands did not match the respective patterns of serotonin and substance P innervation and hyperinnervation previously demonstrated with immunocytochemistry. In some sectors of the inferior olivary complex where both transmitters are presumably co-localized, there was no overlap in the distribution of the respective binding sites either in the normal or in the hyperinnervated state.(ABSTRACT TRUNCATED AT 400 WORDS)     

Distribution of angiotensin IV binding sites (AT4 receptor) in the human forebrain, midbrain and pons as visualised by in vitro receptor autoradiography

Angiotensin IV and other AT₄ receptor agonists, improve memory retention and retrieval in the passive avoidance and swim maze learning paradigms. Angiotensin IV binding sites (also known as the AT₄ receptors) are widely distributed in guinea pig and monkey (Macaca fascicularis) brains where high densities of the binding sites have been detected in the hippocampus, neocortex and motor nuclei. However, the distribution of the binding sites in the human brain is not known. We have recently localised the angiotensin IV binding sites (AT₄ receptors) in post-mortem human brain using iodinated Nle-angiotensin IV, a higher affinity and more stable analogue of angiotensin IV. This radioligand bound with relatively high affinity and specificity to angiotensin IV binding sites. In competition studies on consecutive sections through the prefrontal cortex and claustrum, angiotensin IV, Nle-angiotensin IV and LVV-hemorphin 7 competed for the binding of ¹²⁵I[Nle]-angiotensin IV with nanomolar affinities. Angiotensin II and the AT₁ and AT₂ receptor antagonists were ineffective in competing for the binding at concentrations of up to 10 μM. We found high densities of ¹²⁵I[Nle]-angiotensin IV binding sites throughout the cerebral cortex including the insular, entorhinal, prefrontal and cingulate cortices. Very high densities of the binding sites were observed in the claustrum, choroid plexus, hippocampus and pontine nucleus. Some thalamic nuclei displayed high densities of binding including the anteroprincipal, ventroanterior, anteromedial, medial dorsal and ventrolateral nuclei. The caudate nucleus, putamen, many amygdaloid nuclei and the red nucleus all displayed moderate densities of binding with a higher level detected in the substantia nigra pars compacta. In the hypothalamus, high densities binding sites were found in the ventromedial nucleus with lower levels in the dorsomedial and paraventricular nuclei. The distribution of ¹²⁵I[Nle]-angiotensin IV binding sites in the human brain is similar to that found in other species and supports multiple roles for the binding sites in the central nervous system, including facilitation of memory retention and retrieval.     

Mapping of monoamine neurones and fibres in the cat lower brainstem and spinal cord

Summary The localization of monoaminergic neurones in the medulla oblongata and the pons, and the distribution of catecholaminergic fibres in the spinal cord of the cat were investigated by means of formaldehyde-induced (FIF) or glyoxylic-acid-induced (GIF) fluorescence. Four groups of catecholamine (CA)-containing neurones were found in the following regions: (1) in the ventrolateral medulla oblongata within and adjacent to the lateral reticular nucleus, beginning slightly rostral to the medullo-spinal junction and extending rostrally to the cranial third of the inferior olive; (2) in the commissural, medial and lateral nucleus of the solitary tract; (3) cranial to the first group, closely adjacent to the facial nucleus and the superior olive; and (4) in the dorsolateral pons distributed to different nuclei, namely the nucleus coeruleus and subcoeruleus, the Koelliker-Fuse nucleus, and the medial and lateral parabrachial nuclei. The indoleamine (IA)-containing cell bodies were in general confined to the raphe nuclei, namely the nucleus raphe pallidus, nucleus raphe obscurus, nucleus raphe magnus, nucleus raphe pontis, nucleus raphe dorsalis and the central superior nucleus. A few IA-neurones were located more laterally, especially dorsal and lateral of the cranial half of the inferior olive, around the root of the hypoglossal nerve, in the lateral tegmental field and the pontine central gray. In the spinal cord most CA-fibres were found in the intermediolateral cell column. Another dense accumulation of CA-fibres was located dorsally and laterally of the central canal. The ventral and dorsal horns also contained CA-nervefibres which were slightly more numerous in the sacral spinal cord than in the more rostral parts of the spinal cord.     

An immunocytochemical mapping of methionine-enkephalin-Arg(6)-Gly(7)-Leu(8) in the human brainstem

Using an indirect immunoperoxidase technique, we studied the distribution of immunoreactive fibers and cell bodies containing methionine-enkephalin-Arg(6)-Gly(7)-Leu(8) in the adult human brainstem. Immunoreactive cell bodies were found in the reticular formation of the medulla oblongata (in which we observed the highest density of immunoreactive cell bodies) and the pons, the solitary nucleus, the hypoglossal nucleus, the medial and spinal vestibular nuclei, the lateral cuneate nucleus, the nucleus prepositus, the central gray of the pons and mesencephalon, the central and pericentral nuclei of the inferior colliculus, the superior colliculus, ventral to the superior olive and in the midline region of the pons and mesencephalon. The highest density of immunoreactive fibers containing methionine-enkephalin-Arg(6)-Gly(7)-Leu(8) was found in the spinal trigeminal nucleus, the central gray and the reticular formation of the medulla oblongata, pons and mesencephalon, the solitary nucleus, the spinal vestibular nucleus, the dorsal accessory olivary nucleus, the raphe obscurus, the substantia nigra and in the interpeduncular nucleus. The widespread distribution of immunoreactive structures containing methionine-enkephalin-Arg(6)-Gly(7)-Leu(8) in the human brainstem indicates that this neuropeptide might be involved in several physiological mechanisms, acting as a neurotransmitter and/or neuromodulator.     

Somatostatin- and enkephalin-like immunoreactivities are frequently colocalized in neurons in the caudal brain stem of rat

Summary The medulla oblongata and pons of colchicine treated rats were analyzed with a doublestaining technique using mouse monoclonal antibodies to somatostatin and rabbit polyclonal antibodies raised against methionine-enkephalin. Numerous cells reacted with both antisera but cells reacting with only one antiserum were also observed. Double-stained cells were most frequently encountered at all levels of the nucleus tractus solitarii, in a well defined group in the caudal medullary reticular formation, along the lateral ventral surface of the medulla oblongata, dorsolateral to the inferior olive and in the nucleus raphe magnus. These findings provide further examples of coexistence of two peptides and indicate the possibility that somatostatin-and enkephalin-like peptides are co-released.     

伽玛刀不同剂量照射正常大鼠一侧尾壳核后延髓内Fos蛋白的表达及变化

目的 观察γ－刀不同剂量照射正常大鼠一侧尾壳核后３个月,远离靶区的延髓中尾段内Ｆｏｓ的表达和变化及与剂量的关系。方法 分别用１０Ｇｙ至１００Ｇy１０个级别剂量照 射大 侧尾壳核,３个月后,用ＡＢＣ法对延髓中尾段切片进行抗Ｆｏｓ蛋白的免疫组织化学反应。结果 在延髓内脏带、三叉神经尾侧亚核、三叉神间质核、延髓背侧网状核和下橄榄核等处出现多少不等的Ｆｏｓ阳性细胞：胞核阳性、胞浆阴性;胞浆阳性、胞服性;胞核     

Angiotensin II receptor subtype distribution in the rabbit brain

Previous work has reported that the distribution of AT(1) binding sites in the rabbit brain is similar to that in the rat, but AT(2) binding sites are confined to the septum and cerebellum of the rabbit brain. This receptor autoradiographic study was designed to enhance the detection of angiotensin II binding sites by using greater radioligand concentrations, and to survey the midbrain in more detail than in previous studies. Tissue sections from five rabbit forebrains, three midbrains, and three hindbrains were incubated with 520 pM (125)I-sar(1)ile(8) angiotensin II. The results confirm abundant AT(1) binding in regions involved in cardiovascular and drinking regulation: the nucleus of the solitary tract, ventrolateral medulla, subfornical organ, organum vasculosum of the lamina terminalis, median eminence, and several hypothalamic structures. Novel AT(1) binding sites were discovered in the pituitary, retrorubral field, periolivary region, dorsolateral nucleus of the lateral lemniscus, dorsal raphe, and laterodorsal tegmental nuclei. The distribution of AT(1) binding was similar to the distribution of monoaminergic neurons. AT(2) binding was moderately dense and well visualized in the cerebellum. In contrast to the rat, AT(2) binding was not detected in the inferior olive of the rabbit, but lobe 9 of the cerebellum exhibited a banding pattern of AT(2) binding reminiscent of the pattern of neuronal projections from the inferior olive. It is possible that AT(2) protein is observed at different stages of axonal transport between the inferior olive and the cerebellum in the two species. Our results did identify new AT(2) binding sites in the superior colliculus and cerebral cortex, but it is clear that AT(2) binding in the rabbit brain is weak and is not as widely distributed as in the rat.     

The interrelations between cell groups in the caudal diencephalon of the rat projecting to the striatum and to the medulla oblongata

Summary In order to investigate the topographical relationships between the caudal diencephalic cells of origin of ascending and descending projections in the rat, one fluorescent retrograde tracer was injected into the striatum and another into the medulla oblongata. The medullary injections were mainly centered in the inferior olive. Cells labeled from the striatal injections densely filled the thalamic parafascicular nucleus. Cells labeled from the medullary injections were seen ventrally to the fasciculus retroflexus in the subparafascicular nucleus. The two populations were mixed in a small area at the ventromedial border of the fasciculus retroflexus. No double labeled cells were observed. The present results indicate that caudal diencephalic cells which ascend to the striatum are different from those descending to the medulla oblongata and that they partially overlap.Supported in parts by CNR grants N. 80.00515-04, 81.00283.04     

Somatostatin induced apnoea: prevention by central and peripheral administration of the opiate receptor blocking agent naloxone

Somatostatin (SRIF) (6 nmol) given intracisternally (i.c.) into the alpha-chloralose anaesthetized rat has recently been shown to cause apnoea with a latency of 5-10 minutes (Kalia et al. 1984a). The apnoea produced by SRIF is very rapid, irreversible and leads to the death of the animal. In view of the existence of SRIF nerve cell bodies and terminals in medullary respiratory nuclei such as the ventral and ventrolateral subnuclei of the nucleus of the tractus solitarius (nTS) (Kalia et al. 1984b, Johanson et al. 1984), we have proposed the existence of somatostatinergic mechanisms in the respiratory nuclei of the medulla oblongata involved in mediating apnoeic conditions (Kalia et al. 1984a). In the present study, we have analysed whether the SRIF induced apnoea could be counteracted by a previous i.c. administration of the highly selective alpha 2-adreno-receptor blocking agent RX 781094 (2-(2-(I,4 benzodioxanyl]2-imi-dazoline HCl) (Doxey et al. 1983), or an opiate receptor blocking agent such as naloxone. Thus, both alpha 2-adrenoreceptor agonists and opiates induce respiratory depression, and opiates in high doses cause apnoea (Bolme et al. 1974, Hassen et al. 1982, Sitsen et al. 1982). In addition, catecholamine (CA) and enkephalin immuno-reactive nerve terminal networks exist in high densities within the nucleus tractus solitarius (nTS) of the medulla oblongata and may therefore interact with somatostatin nerve terminals in regulation of respiratory activity (Kalia et al. 1984b).     

Localization of angiotensin converting enzyme by in vitro autoradiography in the rabbit brain

The distribution of angiotensin converting enzyme was examined in the rabbit brain by in vitro autoradiography with the specific radiolabelled inhibitor ¹²⁵I-351A. In the rabbit, the highest concentrations of radioligand binding were found in the choroid plexus, blood vessels, subfornical organ, vascular organ of the lamina terminalis, area postrema and inferior olive. High levels of binding were found throughout the basal ganglia, consistent with the results in all other species studied. In the midbrain the central gray and the superior colliculus displayed high levels of binding. In the medulla oblongata high levels of binding were associated with the nucleus of the solitary tract and dorsal motor nucleus of vagus, consistent with the pattern in other species. There was moderate labelling throughout both the cerebral and cerebellar cortices, which contrasts to the rat but is consistent with the situation in primates. Angiotensin converting enzyme (ACE) is more widely distributed in rabbit brain that in rat, human and Macaca fascicularis, and the results suggest ACE has a very general role in the metabolism of neuropeptides. Inhibitors of converting enzyme are very widely used in the treatment of hypertension and heart disease, and the rabbit should provide a useful model for examining the effects of these drugs in the brain.     

The distribution of glycine receptors in the human brain. A light microscopic autoradiographic study using [3H]strychnine

Glycine receptors were localized autoradiographically in postmortem human brain material using [3H]strychnine as a ligand. Slide mounted tissue sections were labeled in vitro by incubation with [3H]strychnine and autoradiograms obtained using [3H]Ultrofilm. Receptor densities were quantified by computer assisted microdensitometry. No specific binding of [3H]strychnine was observed in any of the forebrain areas studied. Low densities were seen in the midbrain except for dorsal and lateral parts of the periaqueductal grey matter and the oculomotor nuclei. In pons, medulla oblongata and upper cervical cord high densities of [3H]strychnine binding sites were associated with some nuclei including the motor and sensory trigeminal nuclei, the facial and the hypoglossal nuclei. The highest densities of grains were associated with the substantia gelatinosa of the trigeminal nucleus in the medulla oblongata. A peculiar spotty distribution of [3H]strychnine binding sites were found in the gracilis and cuneatus nuclei. The distribution of glycine receptors in the human brain is comparable to that seen in the rat brain, although densities are much higher in the rat. The distribution of glycine receptors in the human brain provides an anatomical substrate for the understanding of the effects of drugs acting in these receptors, particularly strychnine.     

Regional differences in glucocorticoid receptor immunoreactivity among neuropeptide Y immunoreactive neurons of the rat brain

By means of two-colour immunocytochemistry using a mouse monoclonal antibody directed against the rat liver glucocorticoid receptor (GR) and a rabbit polyclonal neuropeptide Y (NPY) antiserum combined with the biotin-avidin immunoperoxidase and a double immunofluorescence procedure, it has been possible to demonstrate nuclear GR immunoreactivity (IR) in neurons showing cytoplasmatic NPY IR in rat brain. The majority of NPY immunoreactive perikarya of the medial parvocellular part of the arcuate nucleus, locus coeruleus and the rostral and caudal part of the ventrolateral medulla oblongata contained strong nuclear GR IR. Many of the NPY immunoreactive neurons present in the subnuclei of the nucleus tractus solitarius also contained nuclear GR IR, while most of the NPY immunoreactive perikarya of the cerebral cortex and all of the neostriatum appeared to lack GR IR. These results indicate that NPY immunoreactive neurons in the upper and lower brain stem, but not in the cerebral cortex and in the neostriatum may be directly involved in mediating central effects of glucocorticoids.