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PubMed1992

Differential anatomical and cellular patterns of connexin43 expression during postnatal development of rat brain.

We have shown previously that connexin43 in the adult rat central nervous system (CNS) is predominantly localized at astrocytic gap junctions. Here we document immunohistochemically the emergence of connexin43-immunoreactive (connexin43-IR) structures and the regional patterns of connexin43 expression during postnatal maturation of the rat brain. On Western blots, connexin43 was detected in brain samples at postnatal day (P) 5, the earliest age studied. Immunohistochemically, most brain regions displayed a characteristic sequence of transient immunoreactive profiles that ultimately gave rise to the uneven distribution of the protein seen in adults. Generally, brains at P1-P5 exhibited long, fibrous connexin43-IR elements which were identified as radial glial cells. This fibrous immunostaining was considerably diminished at P5 and was replaced by short immunoreactive processes which predominated up to P10. These processes had a stellate appearance, emanated from partially stained astrocytic cell bodies and were heterogeneously distributed throughout the developing brain. By P15, there occurred only punctate immunolabelling similar to that seen in adult brain. Some brain regions including the amygdaloid complex, septohypothalamic nucleus, preoptic hypothalamus, zona incerta, ependyma and subfornical organ were exceptional in that they displayed adult immunostaining patterns at early postnatal ages suggesting a precocious maturation of gap junctions in these areas. We conclude that the highly heterogeneous distribution of connexin43-immunoreactivity among defined nuclear structures in adult brain does not reflect an antecedent requirement for connexin43 in early brain morphogenesis, but rather is related to the development of neuronal activity, the establishment of functional circuitry and the contribution of astrocytic gap junctions to glial metabolic coupling and potassium spatial buffering in the mature CNS.

Animals↗
PubMed2003

Effects of basolateral amygdala dopamine depletion on the nucleus accumbens and medial prefrontal cortical dopamine responses to stress.

In vivo voltammetry was used to study the effects of basolateral amygdala dopamine depletion on stress-induced dopamine release in the nucleus accumbens and medial prefrontal cortex. Male Long-Evans rats received bilateral microinjections of 6-hydroxydopamine or vehicle into the basolateral amygdala. Changes in dopamine signal were monitored in the nucleus accumbens and in the right and left hemispheres of medial prefrontal cortex, in lesioned animals and shams. Animals were subjected to a physical stressor (tail pinch) and a species-typical threat (fox odour); each stressor was presented twice over four consecutive daily sessions. The results indicate that the nucleus accumbens dopamine responses to both stressors are significantly potentiated by dopamine-depleting lesions to basolateral amygdala. In contrast, while the dopamine stress response in the left medial prefrontal cortex did not differ between lesioned animals and shams, the right medial prefrontal cortical dopamine response to tail pinch, but not fox odour stress, was significantly attenuated in lesioned animals. Therefore, basolateral amygdala dopamine depletion had opposite effects on the nucleus accumbens and medial prefrontal cortical dopamine responses to stress, although the effect on the latter is lateralized to the right hemisphere in a stressor-specific manner. These data indicate that stress-induced activation of meso-amygdaloid dopamine exerts an inhibitory influence on the nucleus accumbens dopamine response to stress. They also suggest the possibility that meso-amygdaloid dopamine influences the nucleus accumbens dopamine response to stress indirectly by modulating stress-induced dopamine release in medial prefrontal cortex. These findings add to a growing body of evidence of a preferential involvement of right medial prefrontal cortical dopamine in a wide range of physiological responses to stress.

Amygdala↗
PubMedDate not supplied

Immunohistochemical mapping of galanin-like neurons in the rat central nervous system.

Using an antiserum generated in rabbits against synthetic galanin (GA) and the indirect immunofluorescence method, the distribution of GA-like immunoreactive cell bodies and nerve fibers was studied in the rat central nervous system (CNS) and a detailed stereotaxic atlas of GA-like neurons was prepared. GA-like immunoreactivity was widely distributed in the rat CNS. Appreciable numbers of GA-positive cell bodies were observed in the rostral cingulate and medial prefrontal cortex, the nucleus interstitialis striae terminalis, the caudate, medial preoptic, preoptic periventricular, and preoptic suprachiasmatic nuclei, the medial forebrain bundle, the supraoptic, the hypothalamic periventricular, the paraventricular, the arcuate, dorsomedial, perifornical, thalamic periventricular, anterior dorsal and lateral thalamic nuclei, medial and central amygdaloid nuclei, dorsal and ventral premamillary nuclei, at the base of the hypothalamus, in the central gray matter, the hippocampus, the dorsal and caudoventral raphe nuclei, the interpeduncular nucleus, the locus coeruleus, ventral parabrachial, solitarii and commissuralis nuclei, in the A1, C1 and A4 catechaolamine areas, the posterior area postrema and the trigeminal and dorsal root ganglia. Fibers were generally seen where cell bodies were observed. Very dense fiber bundles were noted in the septohypothalamic tract, the preoptic area, in the hypothalamus, the habenula and the thalamic periventricular nucleus, in the ventral hippocampus, parts of the reticular formation, in the locus coeruleus, the dorsal parabrachial area, the nucleus and tract of the spinal trigeminal area and the substantia gelatinosa, the superficial layers of the spinal cord and the posterior lobe of the pituitary. The localization of the GA-like immunoreactivity in the locus coeruleus suggests a partial coexistence with catecholaminergic neurons as well as a possible involvement of the GA-like peptide in a neuroregulatory role.

Animals↗
PubMed1998

Immunohistochemical distribution of cannabinoid CB1 receptors in the rat central nervous system.

Immunohistochemical distribution of cannabinoid receptors in the adult rat brain was studied using specific purified antibodies against the amino-terminus of the CB1 receptor. Our results generally agree well with the previous studies using CB1 receptor autoradiography and messenger RNA in situ hybridization. However, because of its greater resolution, immunohistochemistry allowed identification of particular neuronal cells and fibers that possess cannabinoid receptors. CB1-like immunoreactivity was found in axons, cell bodies and dendrites, where it appeared as puncta in somata and processes. Both intensely and moderately or lightly stained neurons were observed. The intensely stained neurons were dispersed and only occur in cortical structures including hippocampal formation and olfactory bulb. Moderately or lightly stained neurons were found in caudate-putamen and amygdala. In the hippocampal formation only intensely stained neurons were observed. The cell bodies of pyramidal neurons in CA1 and CA3 fields appeared to be unstained but surrounded by a dense plexus of immunoreactive fibers. The granule cells in the dentate area were also immunonegative. Many intensely stained neurons were located at the base of the granule cell layer. CB1-like immunoreactive neurons and fibers were also found in the somatosensory, cingulate, perirhinal, entorhinal and piriform cortices, in claustrum, amygdaloid nuclei, nucleus accumbens and septum. Beaded immunoreactive fibers were detected in periaqueductal gray, nucleus tractus solitarius, spinal trigeminal tract and nucleus, dorsal horn and lamina X of the spinal cord. A triangular cap-like mass of immunoreactivity was found to surround the basal part of the Purkinje cell body in the cerebellum. Only small, lightly stained cells were found in the molecular layer in the cerebellum close to the Purkinje cell layer. The CB1 receptor is widely distributed in the forebrain and has a more restricted distribution in the hindbrain and the spinal cord. It appears to be expressed on cell bodies, dendrites and axons. According to the location and morphology, many, but not all, CB1-like immunoreactive neurons appear to be GABAergic. Therefore, cannabinoids and cannabinoid receptors may play a role in modulating GABAergic neurons.

Animals↗
PubMed2003

Immunohistochemical distribution of NTS2 neurotensin receptors in the rat central nervous system.

In the present study, we localized the levocabastine-sensitive neurotensin receptor (NTS2) protein in adult rat brain by using an N-terminally-directed antibody. NTS2-like immunoreactivity was broadly distributed throughout the rat brain. At the cellular level, the reaction product was exclusively associated with neurons and predominantly, although not exclusively, with their dendritic arbors. No NTS2 signal was observed over astrocytes, as confirmed by dual confocal microscopic immunofluorescence studies using the astrocytic marker S100beta. High densities of NTS2-like immunoreactive nerve cell bodies and/or processes were detected in many regions documented to receive a dense neurotensinergic innervation, such as the olfactory bulb, bed nucleus of the stria terminalis, magnocellular preoptic nucleus, amygdaloid complex, anterodorsal thalamic nucleus, substantia nigra, ventral tegmental area, and several brainstem nuclei. Most conspicuous among the latter were structures implicated in the descending control of nociceptive inputs (e.g., the periaqueductal gray, dorsal raphe, gigantocellular reticular nucleus, pars alpha, lateral paragigantocellular, and raphe magnus), in keeping with the postulated role of NTS2 receptors in the mediation of neurotensin's supraspinal antinociceptive actions. However, the distribution of NTS2-like immunoreactivity largely exceeded that of neurotensin terminal fields, and some of the highest concentrations of the receptor were found in areas devoid of neurotensinergic inputs such as the cerebral cortex, the hippocampus, and the cerebellum, suggesting that neurotensin may not be the exclusive endogenous ligand for this receptor subtype.

Animals↗
PubMed1981

Comparative immunocytochemical localization of putative opioid ligands in the central nervous system.

We report a detailed comparative immunocytochemical mapping of enkephalin, CCK and ACTH/beta-endorphin immunoreactive nerves in the central nervous system of rat and guinea pig. Enkephalin immunoreactivity was detected in many groups of nerve cell bodies, fibers and terminals in the limbic system, basal ganglia, hypothalamus, thalamus, brain stem and spinal cord. beta-endorphin and ACTH immunoreactivity was limited to a single group of nerve cell bodies in and around the arcuate nucleus and in fibers and terminals in the midline areas of the hypothalamus, thalamus and mesencephalic periaqueductal gray with lateral extensions to the amygdaloid area. Cholecystokinin immunoreactive nerve fibers and terminals displayed a distribution similar to that of enkephalin in many regions; but striking differences were also found. An immunocytochemical doublestaining technique, which allowed simultaneous detection of two different peptides in the same tissue section, showed that enkephalin-, CCK- and ACTH/beta-endorphin-immunoreactive nerves although closely intermingled in many brain areas, occurred separately. The distributions of nerve terminals containing these neuropeptides showed striking overlaps and also paralleled the distribution of opiate receptors. This may suggest that enkephalin, CCK, ACTH and beta-endorphin may interact with each other and with opiate receptors.

Adrenocorticotropic Hormone↗
PubMed1989

Coexistence of somatostatin with neuropeptide Y, but not with cholecystokinin or vasoactive intestinal peptide, in neurons of the rat amygdala.

A two-color immunoperoxidase procedure was used to determine whether somatostatin (SOM) containing neurons in the amygdala also contain neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), or cholecystokinin (CCK). There was no evidence that SOM-containing neurons in any of the amygdaloid nuclei contain VIP or CCK. In contrast, there was extensive colocalization of SOM and NPY in all of the amygdaloid nuclei with the exception of the intercalated masses and the lateral subdivision of the central nucleus. The greatest number of SOM-NPY double-labeled cells was observed in the medial nucleus, lateral nucleus, and intra-amygdaloid portion of the bed nucleus of the stria terminalis. The morphology of these SOM-NPY neurons was similar in all nuclei. Most exhibited fusiform or ovoid cell bodies with one or two sparsely branched dendrites emerging from each pole of the cell. The extensive coexistence of SOM and NPY in non-pyramidal neurons of the basolateral amygdala is similar to that seen in the cerebral cortex and supports the concept that these brain regions share many important characteristics. The extensive colocalization of SOM and NPY in the medial amygdala, in conjunction with the results of previous studies, suggests that some of these cells may project to the bed nucleus of the stria terminalis and hypothalamus.

Amygdala↗
PubMed1983

Religious and mystical experiences as artifacts of temporal lobe function: a general hypothesis.

Mystical and religious experiences are hypothesized to be evoked by transient, electrical microseizures within deep structures of the temporal lobe. Although experiential details are affected by context and reinforcement history, basic themes reflect the inclusion of different amygdaloid-hippocampal structures and adjacent cortices. Whereas the unusual electrical coherence allows access to infantile memories of parents, a source of good expectations, specific stimulation evokes out-of-body experiences, space-time distortions, intense meaningfulness, and dreamy scenes. The species-specific similarities in temporal lobe properties enhance the homogeneity of cross-cultural experiences. They exist along a continuum that ranges from "early morning highs" to recurrent bouts of conversion and dominating religiosity. Predisposing factors include any biochemical or genetic factors that produce temporal lobe lability. A variety of precipitating stimuli provoke these experiences, but personal (life) crises and death bed conditions are optimal. These temporal lobe microseizures can be learned as responses to existential trauma because stimulation is of powerful intrinsic reward regions and reduction of death anxiety occurs. The implications of these transients as potent modifiers of human behavior are considered.

Culture↗
PubMed1998

Neurons containing hypocretin (orexin) project to multiple neuronal systems.

The novel neuropeptides called hypocretins (orexins) have recently been identified as being localized exclusively in cell bodies in a subregion of the tuberal part of the hypothalamus. The structure of the hypocretins, their accumulation in vesicles of axon terminals, and their excitatory effect on cultured hypothalamic neurons suggest that the hypocretins function in intercellular communication. To characterize these peptides further and to help understand what physiological functions they may serve, we undertook an immunohistochemical study to examine the distribution of preprohypocretin-immunoreactive neurons and fibers in the rat brain. Preprohypocretin-positive neurons were found in the perifornical nucleus and in the dorsal and lateral hypothalamic areas. These cells were distinct from those that express melanin-concentrating hormone. Although they represent a restricted group of cells, their projections were widely distributed in the brain. We observed labeled fibers throughout the hypothalamus. The densest extrahypothalamic projection was found in the locus coeruleus. Fibers were also seen in the septal nuclei, the bed nucleus of the stria terminalis, the paraventricular and reuniens nuclei of the thalamus, the zona incerta, the subthalamic nucleus, the central gray, the substantia nigra, the raphe nuclei, the parabrachial area, the medullary reticular formation, and the nucleus of the solitary tract. Less prominent projections were found in cortical regions, central and anterior amygdaloid nuclei, and the olfactory bulb. These results suggest that hypocretins are likely to have a role in physiological functions in addition to food intake such as regulation of blood pressure, the neuroendocrine system, body temperature, and the sleep-waking cycle.

Animals↗
PubMed1984

Immunohistochemical distribution of somatostatin-like immunoreactivity in the central nervous system of the adult rat.

The localization and distribution of somatostatin (growth hormone release-inhibiting hormone; somatotropin release-inhibiting factor) have been studied with the indirect immunofluorescence technique of Coons and collaborators and the immunoperoxidase method of Sternberger and coworkers using specific and well-characterized antibodies to somatostatin, providing semiquantitative, detailed maps of somatostatin-immunoreactive cell profiles and fibers. Our results demonstrate a widespread occurrence of somatostatin-positive nerve cell bodies and fibers throughout the central nervous system of adult, normal or colchicine-treated, albino rats. The somatostatin cell bodies varied in size from below 10 micron up to 40 micron in diameter and could have only a few or multiple processes. Dense populations of cell somata were present in many major areas including neocortex, piriform cortex, hippocampus, amygdaloid complex, nucleus caudatus, nucleus accumbens, anterior periventricular hypothalamic area, ventromedial hypothalamic nucleus, nucleus arcuatus, medial to and within the lateral lemniscus, pontine reticular nuclei, nucleus cochlearis dorsalis and immediately dorsal to the nucleus tractus solitarii. Extensive networks of nerve fibers of varying densities were also found in most areas and nuclei of the central nervous system. Both varicose fibers as well as dot- or "dust-like" structures were seen. Areas with dense or very dense networks included nucleus accumbens, nucleus caudatus, nucleus amygdaloideus centralis, most parts of the hypothalamus, nucleus parabrachialis, nucleus tractus solitarii, nucleus ambiguus, nucleus tractus spinalis nervi trigemini and the dorsal horn of the spinal cord. One exception is the cerebellum which only contained few somatostatin-positive cell bodies and nerve fibers. It should be noted that somatostatin-positive cell bodies and fibers did not always conform to the boundaries of the classical neuroanatomical nuclei, but could often be found in areas between these well-established nuclei or occupying, in varying concentrations, only parts of such nuclei. It was difficult to identify with certainty somatostatin-immunoreactive axons in the animals studied. Some pathways could, however, be demonstrated, but further experimental studies are necessary to elucidate the exact projections of the somatostatin-immunoreactive neurons in the rat central nervous system.

Animals↗
PubMed1988

Ontogeny of calcitonin gene-related peptide-immunoreactive structures in the rat forebrain and diencephalon.

Ontogeny of the calcitonin gene-related peptide (CGRP)-containing structures was investigated in the forebrain and diencephalon of the rat by means of indirect immunofluorescence. CGRP-like immunoreactive (CGRP-IR) fibers first appeared at gestational day 18 (E18) in the primordia of the bed nucleus of the stria terminalis, central amygdaloid nucleus and posterolateral portion of the lateral hypothalamic nucleus. CGRP-IR fibers gradually increased in immunoreactivity and in number in these nuclei toward birth. A pronounced increase of CGRP-like immunoreactive fibers was found after birth in these nuclei and made very dense plexuses of fibers in adult animals. A few CGRP-IR fibers first appeared at the perinatal stage in the lateral septum, the most caudal portion of the caudate-putamen, and ventromedial and ventroposterior thalamic nuclei. Then the immunoreactive fibers increased and dense plexuses were present in these brain areas of the adult. A small number of immunoreactive fibers appeared at postnatal day 4-7 (P4-7) in the caudal insular cortex and ventromedial hypothalamic nucleus. A significant number of fibers was present in these areas of the adult. On the other hand, CGRP-like immunoreactivity in cell bodies was first detected with faint immunofluorescence at P4 in the anteromedial parts of the lateral hypothalamic area and ventromedial and ventroposterior thalamic nuclei. Thereafter CGRP-IR cells increased in immunoreactivity, and a significant number of cells was noted in these nuclei of the adult. In addition, CGRP-IR cells are identified in the medial amygdaloid nucleus, and medial preoptic area at P14. In conclusion, in the forebrain and diencephalon (1) CGRP-like immunoreactivity appears in fibers earlier than in cell bodies, suggesting that at least some of immunoreactive fibers originate from the lower brainstem, and (2) high density of CGRP-IR structures present in the brain at embryonic and early postnatal stages may indicate that CGRP could be an important factor involved in the developmental organization of the central nervous system.

Aging↗
PubMed1992

Distribution of neuropeptide Y-like immunoreactivity in the brain of the lizard Gallotia galloti.

The distribution of neuropeptide Y (NPY)-like immunoreactivity was studied in the brain of the lizard Gallotia galloti, in order to gain insight into the comparative topography of this peptide. Antisera against both NPY and its C-terminal flanking peptide (C-PON) were used, demonstrating a general coexistence of both peptides, as described in other vertebrates. Most NPY-like immunoreactive (NPY-LI) cell bodies were observed in the telencephalon, specifically in various olfactory structures, all cortices, septum, basal ganglia (except for the globus pallidus), the nucleus of the diagonal band of Broca, the amygdaloid complex, and the bed nucleus of the anterior commissure. NPY-LI cells were also seen in the preoptic and hypothalamic regions and the dorsal thalamus (mainly in the perirotundal belt), as well as in the mesencephalic tegmentum (in the ventral tegmental area, the substantia nigra, and the retrorubral area). NPY-LI fibers and terminals were widely distributed in the brain. All visual and auditory neuropiles were densely innervated. Specially dense plexuses were seen in the nucleus accumbens, the ventral pallidum, the suprachiasmatic and ventromedial hypothalamic nuclei, the nucleus medialis thalami, the left habenula, and the central nucleus of the torus semicircularis. Our analysis shows that the distribution of NPY-like immunoreactivity in the forebrain of Gallotia largely resembles that of other vertebrates, whereas differences are mainly observed in the brainstem. The widespread distribution of NPY in the lizard brain suggests several modulatory functional roles, either in local-circuit systems of the forebrain, or in various limbic, neuroendocrine, and sensory pathways.

Animals↗
PubMed1982

Neocortical and basal telencephalic origins of the anterior commissure of the cat.

The neocortical and basal telencephalic origins of the anterior commissure of the cat have not been described in earlier studies of the great cerebral commissures. In this anatomical study, all cerebral commissures, except the anterior commissure, of twelve cats were first transected. Subsequent unilateral injections of large quantities of horseradish peroxidase throughout the right hemisphere revealed the entire origins of the three branches of the anterior commissure in the left hemisphere. Since the anterior commissure was the only interhemispheric fibre system remaining, only the cells, fibres and anterogradely-labelled terminals of the anterior commissure were labelled by horseradish peroxidase in the uninjected hemisphere. Approximately three-quarters of the neurons of the anterior commissure are in the neocortex, mostly in layers V and VI. These neocortical cells occupy an extensive field stretching from gyrus proreus to the posterior ectosylvian gyrus and from the rhinal sulcus to the suprasylvian sulcus. Other fibres of the anterior commissure, however, were found to have their cell bodies in regions not considered part of the neocortex, and these included the anterior olfactory nucleus, the pyriform cortex, olfactory tubercles, nucleus of the lateral olfactory tract, part of the amygdaloid nuclei, the periamygdaloid nucleus and the lateral entorhinal area. Finally, it was found that the fibres of the anterior commissure do not have an exclusive neocortical territory from which cells of other commissural fibres are excluded. Rather, there appears to be a substantial overlap between the field of origin of fibres of the anterior commissure and those of the largest cerebral commissure, the corpus callosum. The disposition of this field may help to explain why visual information fails to transfer between the hemispheres in cats whose corpus callosum has been cut, in contrast to the success of such transfer in primates.

Animals↗
PubMed1997

Reciprocal regional changes in brain NPY receptor density during dietary restriction and dietary-induced obesity in the rat.

Neuropeptide Y (NPY) potently induces feeding, reduces thermogenesis and induces obesity in rats when injected into the cerebral ventricles. Groups of male Wistar rats were either restricted to 60% of their normal daily food intake over 10 days or made obese by presenting them with a high-calorie diet rich in sugars and fat over 6 weeks. Food restricted rats lost up to 20% of their body weight, compared with control rats and had large reductions in their body fat mass. By contrast, rats with dietary-induced obesity weighed 26% more than controls due mainly to increased body fat mass. Quantitative receptor autoradiography demonstrated reduced [(125)I]PYY binding in the hypothalamic lateral (perifornical) and dorsal areas, hypothalamic ventromedial, arcuate and dorsomedial nuclei, hippocampal CA3 region, centromedial amygdaloid nucleus and thalamic paraventricular and reuniens nuclei in dietary restricted rats compared with controls. By contrast, regional [(125)I]PYY binding was significantly increased in hypothalamic lateral and dorsal areas, hypothalamic arcuate and dorsomedial nuclei, amygdaloid medial and centromedial nuclei, thalamic centromedial and paraventricular nuclei of dietary obese rats versus controls. Masking NPY Y1 receptors with 1 microM BIBP3226, a selective Y1 receptor antagonist, revealed that the changes in [(125)I]PYY binding in brains of food-restricted and dietary-obese rats were due to changes in BIBP3226-insensitive binding sites, presumably Y2 or Y5 NPY receptors. These data suggest that dietary-restriction stimulates NPY release resulting in down-regulation of NPY Y5 'feeding' and/or Y2 receptors and reduced BAT thermogenesis thereby providing an increased drive to eat to restore normal caloric intake whilst reducing thermogenesis in order to conserve fat reserves. By contrast, the up-regulation of NPY Y5 and/or Y2 receptors in dietary-induced obesity is consistent with inhibition of NPY release in the hypothalamus, amygdala and thalamus. Overall, we suggest that there is a regional increase in NPY release during negative energy balance, such as during food-restriction and a reduced regional release of NPY in positive energy balance, such as during hyperphagia associated with the development of obesity.

Amygdala↗
PubMed1999

Naltrexone affects cocaine self-administration in naïve rats through the ventral tegmental area rather than dopaminergic target regions.

Behavioural studies have shown an involvement of central endogenous opioid systems in experimental cocaine addiction. Seeking to further localize the attenuating effect of opioid blockade on the reinforcing effects of cocaine, naltrexone was administered locally to different regions of the mesocorticolimbic system, which are thought to be critically involved in cocaine self-administration behaviour. Both cell body and nerve terminal regions of this system were targeted. Using a model for the initiation of cocaine self-administration behaviour, no effect of naltrexone was found in caudate, amygdaloid or accumbens nuclei, nor in the medial prefrontal cortex. However, blockade of endogenous opioid receptors in the ventral tegmental area region attenuated cocaine self-administration. With the initiation model, this finding reflects an attenuating effect on the reinforcing effects of cocaine. The attenuation of self-administration was dependent on the naltrexone dose. The present findings suggest that endogenous opioid systems in the ventral tegmental area modulate the reinforcing efficacy of cocaine.

Animals↗
PubMedDate not supplied

Autoradiographic distribution of 125I calcitonin gene-related peptide binding sites in the rat central nervous system.

Using autoradiographic method and 125I-Tyro rat CGRP as a ligand, receptor binding sites were demonstrated in the rat central nervous system. Saturation studies and Scatchard analysis of CGRP-binding to slide mounted tissue sections containing primarily cerebellum showed a single class of receptors with a dissociation constant of 0.96 nM and a Bmax of 76.4 fmol/mg protein. 125I-Tyro rat CGRP binding sites were demonstrated throughout the rat central nervous system. Dense binding was observed in the telencephalon (medial prefrontal, insular and outer layers of the temporal cortex, nucleus accumbens, fundus striatum, central and inferior lateral amygdaloid nuclei, most caudal caudate putamen, organum vasculosum laminae terminalis, subfornical organ), the diencephalon (anterior hypothalamic, suprachiasmatic, arcuate, paraventricular, dorsomedial, periventricular, reuniens, rhomboid, lateral thalamic pretectalis and habenula nuclei, zona incerta), in the mesencephalon (superficial layers of the superior colliculus, central nucleus of the geniculate body, inferior colliculus, nucleus of the fifth nerve, locus coeruleus, nucleus of the mesencephalic tract, the dorsal tegmental nucleus, superior olive), in the molecular layer of the cerebellum, in the medulla oblongata (inferior olive, nucleus tractus solitarii, nucleus commissuralis, nuclei of the tenth and twelfth nerves, the prepositus hypoglossal and the gracilis nuclei, dorsomedial part of the spinal trigeminal tract), in the dorsal gray matter of the spinal cord (laminae I-VI) and the confines of the central canal. Moderate receptor densities were found in the septal area, the "head" of the anterior caudate nucleus, medial amygdaloid and bed nucleus of the stria terminalis, the pyramidal layers of the hippocampus and dentate gyri, medial preoptic area, ventromedial nucleus, lateral hypothalamic and ventrolateral thalamic area, central gray, reticular part of the substantia nigra, parvocellular reticular nucleus. Purkinje cell layer of the cerebellum, nucleus of the spinal trigeminal tract and gracile fasciculus of the spinal cord. The discrete distribution of CGRP-like binding sites in a variety of sensory systems of the brain and spinal cord as well as in thalamic and hypothalamic areas suggests a widespread involvement of CGRP in a variety of brain functions.

Animals↗
PubMed1993

An aromatase-associated cytoplasmic inclusion, the "stigmoid body," in the rat brain: II. Ultrastructure (with a review of its history and nomenclature).

The ultrastructure of aromatase-associated "stigmoid (dot-like) structures," which were detected in a previous study using light-microscopic immunohistochemistry (Shinoda et al.: J. Comp. Neurol. 322:360-376, '92), were examined in the rat medial preoptic region, bed nucleus of the stria terminalis, medial amygdaloid nucleus, and arcuate nucleus by pre- and post-embedding marking with a polyclonal antibody against human placental antigen X-P2 (hPAX-P2) for immuno-electron microscopic analysis. The immunoreactive stigmoid structure was identified as a distinct, non-membrane-bounded cytoplasmic inclusion (approximately 1-3 microns in diameter), which has a granulo-fuzzy texture with moderate-to-low electron density in non-immunostained preparations. It consists of at least four distinct granular and three distinct fibrillo-tubular elements forming a granulo-fibrillar conglomerate. This type of inclusions was formally termed the "stigmoid body" under the electron microscope. The stigmoid body is composed of the outer granulo-fibrillar and inner hyaloplasmic compartments. The immunoreactivity for hPAX-P2 is mainly localized to the former, especially to the low density granulo-fuzzy materials associated with the fibrillo-tubular elements. Identification of the ultrastructure of stigmoid body clarified their prevalence not only in the limbic and hypothalamic regions, but also in sex-steroid-sensitive peripheral tissues (e.g., peripheral sensory ganglia, ovary, testis) by consulting earlier electron-microscopic studies. Reviewing the history and nomenclature of this inclusion body, we reorganized the terminology of related neuronal cytoplasmic inclusions, the terms of which have often been confused, and discussed its functional significance on the basis of the present and previously accumulated data. In conclusion, we emphasized the importance of the stigmoid bodies in the sex-steroid-sensitive neural system because of their large size, high frequency, specific distribution in brains and peripheral tissues, effects of sex-steroids, and immunological and histochemical characteristics of the antibody marking the inclusion. The stigmoid bodies may provide a subcellular site for sex-steroid metabolism in their target tissues and play a critical role in cytosolic modulation of their actions (e.g., by aromatization) prior to their receptor binding.

Amygdala↗
PubMed1989

Auditory forebrain organization of an Australian marsupial, the northern native cat (Dasyurus hallucatus).

Structures and connections of auditory forebrain regions of the Northern native cat, a member of one of the most primitive families among Australian marsupials, have been examined anatomically by using anterograde and retrograde tracing techniques with wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) after defining the acoustically responsive neocortical area physiologically. The structure of the medial geniculate body (MG) was similar to that described in other species. The results obtained from a case with a WGA-HRP injection into the MG showed that the MG strongly projects to the lateral amygdaloid nucleus (LAmy) and the putamen as well as the auditory neocortex (ACx). Results obtained from other cases with WGA-HRP injections into the physiologically defined ACx show also that the ACx is connected not only with the ipsilateral MG and the contralateral ACx but also with the LAmy both bilaterally and reciprocally. The regions within the LAmy in which the MG-LAmy projection fibers terminate largely overlap with those in which the ACx-LAmy fibers terminate and the LAmy-ACx pathway originates. The connectional relationships revealed in the present study--that the LAmy receives auditory information from the MG and reciprocates auditory information with the ACx bilaterally--strongly suggest that, in some primitive mammals with small neocortical areas, a specific portion of noncortical telencephalon functions as an auditory center and occupies a relatively large volume of space in the forebrain. It is possible that the auditory sector of noncortical telencephalon in some primitive mammals such as the American Didelphidae and the Australian Dasyuridae is homologous with part of the auditory sector of the dorsal ventricular ridge (DVR) in reptiles and birds and also may have functions shared with the auditory primary and association neocortex in advanced mammals such as the domestic cat and the monkey (Kudo et al., '86a).

Animals↗