1B1075: a brain- and pituitary-specific mRNA that encodes a novel chromogranin/secretogranin-like component of intracellular vesicles

The rat 1B1075 mRNA encodes a 533-residue novel chromogranin/secretogranin-like acidic protein that contains an apparent secretion signal, several pairs of tandem basic residues, and internally repeated sequence elements. 1B1075 transcripts are detected, by blotting and in situ hybridization, at the highest levels in the neocortex, hippocampus, cerebellar cortex, selected pontine and diencephalic nuclei, and presumptive pituitary corticotrophs, at lower levels in specific nuclei in most other brain regions, but in none of several other tissues. Utilizing antisera to several nonoverlapping synthetic peptide fragments of the predicted protein sequence, we detect a brain- and pituitary-specific 57-kDa protein in cellular processes and fiber tracts, generally consistent with axonal transport from the cell bodies identified by in situ hybridization. Ultrastructural studies demonstrate that this protein is a component of intraneuronal vesicles in axons and vesicle-like structures in dendrites. Based on these data, we suggest the name Secretogranin III for the 1B1075 gene product. In related collaborative studies, a mouse deleted for the 1B1075-homologous gene has been produced that should allow assessment of its physiological role.

A major direct GABAergic pathway from zona incerta to neocortex

Retrograde fluorescent tracers were used to demonstrate a previously unknown but sizable direct gamma-aminobutyric acid (GABA)-containing neuronal pathway from the zona incerta to the neocortex in rats. This incertocortical pathway was found to project bilaterally to the entire neocortex and exhibited a rough corticotopic organization. Many of the zona incerta neurons projecting to the parietal and occipital cortices could also be immunohistochemically stained with antibodies to glutamic acid decarboxylase and GABA. Few of these neurons were immunoreactive to tyrosine hydroxylase antibodies, which identify dopamine-containing neurons. Injections in the frontal and entorhinal cortices labeled many neurons near or within the dopaminergic A13 subdivision of the zona incerta. In addition, the incertocortical system was found to be significantly larger during early postnatal (2 to 3 weeks) development. The projection pattern of this newly discovered pathway resembles that of the monoaminergic and cholinergic systems, arising from the brainstem and forebrain, suggesting possible similarities of function.

Neuropeptide Y localization in telencephalic and diencephalic structures of the ground squirrel brain

The distribution of neuropeptide Y-immunoreactive (NPY-IR) perikarya, fibers, and terminals was investigated in the brain of two species of hibernatory ground squirrels, Spermophilus tridecemlineatus and S. richardsonii, by means of immunohistochemistry. In the telencephalic and diencephalic structures studied, distinct patterns of NPY-IR were observed which were essentially identical in male and female animals of both species. No differences in amount or distribution of NPY-IR structures were observed between animals which had been in induced hibernation for several months before sacrifice in March/April and those sacrificed one week after their capture in May. In some brain structures (e.g., the hypothalamic arcuate nucleus), IR cell bodies were observed only after pretreatment with colchicine. NPY-IR perikarya and fibers were found in the cerebral cortex, caudate nucleus-putamen, and dorsal part of the lateral septal nucleus. Dense fiber plexuses were seen in the lateral and medial parts of the bed nucleus of the stria terminalis. The numbers of IR perikarya observed in the medial part of the nucleus increased following intraventricular colchicine injections. The accumbens nucleus exhibited few IR cells and many fibers. Claustrum and endopiriform nuclei showed a considerable number of stained cells and fibers that increased in number and staining intensity in colchicine-treated ground squirrels. The induseum griseum showed a small band of IR cell bodies and varicose fibers. Bipolar of multipolar IR cells and varicose fibers were found in the basal nucleus of the amygdala. Dense fiber plexuses as well as IR terminals were seen in the median, medial, and lateral preoptic areas of the hypothalamus. Terminals and relatively few fibers were located in the periventricular, paraventricular, and supraoptic nuclei. The anterior, lateral, dorsomedial, and ventromedial hypothalamic nuclei contained relatively large numbers of terminals and fibers. In the suprachiasmatic nuclei, dense terminals were distributed mainly in the ventromedial subdivision. In the median eminence, immunoreactive terminals were concentrated in the external layer, with fibers predominant in the internal layer. NPY-IR perikarya were observed only in the arcuate nucleus of the hypothalamus and only following colchicine treatment. In the epithalamus (superficial part of the pineal gland and habenular nuclei), varicose fibers appeared mainly in perivascular locations (pineal) or as a dense plexus (habenular nuclei). These results from ground squirrels are discussed in comparison to those obtained in other species and with regard to considerations of the physiological role of NPY.

Presence of dopamine-immunoreactive cell bodies in the catecholaminergic group A15 of the sheep brain

Antisera were raised in rabbits against dopamine or noradrenaline conjugated to thyroglobulin with glutaraldehyde. These antisera, tested in enzyme linked immunosorbent assay and immunohistochemistry specifically recognized their homologous antigens. With the aid of anti-tyrosine hydroxylase, anti-aromatic aminoacid decarboxylase, anti-dopamine-beta-hydroxylase, anti-dopamine, and anti-noradrenaline antisera, immunohistochemical reactions were performed on glutaraldehyde fixed sections of sheep diencephalon in order to determine the presence of dopamine in the catecholaminergic group A15. Perikarya of this nucleus were stained with anti-tyrosine hydroxylase, anti-aromatic aminoacid decarboxylase and anti-dopamine, but not with anti-dopamine-beta-hydroxylase or anti-noradrenaline. Both of these latter antisera stained fibers within this area. So as recently found in the rat, we could conclude that dopamine is present in group A15 of the sheep.

Synaptic organization of septal projections in the rat medial habenula: a wheat germ agglutinin-horseradish peroxidase and immunohistochemical study

The synaptic organization of septal inputs to the rat habenular complex of the dorsal diencephalon was examined employing the anterograde tracer wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). The cellular distribution of substance P (SP) and choline acetyltransferase (ChAT) immunoreactivity was also studied at the light and electron microscopic level. Following placements of tracer within the entire septum, labeled axons were observed in the stria medullaris and in the medial and lateral subnuclei of the habenula. Following injections of tracer in the nuclei triangularis and septofimbrialis of the posterior septum, the medial subnucleus was heavily labeled, whereas the lateral subnucleus was devoid of peroxidase activity. The medial subnucleus possessed labeled myelinated axons and terminals that contained clear, spherical vesicles and formed asymmetric contacts with dendritic spines and shafts. Terminals possessing WGA-HRP activity also formed non-synaptic junctions with other labeled or unlabeled terminals. SP and ChAT immunoreactivity in normal and colchicine-treated animals was confined to dendrites and somata within the medial habenula. Terminals containing clear spherical vesicles formed asymmetric synaptic contacts with these immunoreactive somatic and dendritic profiles. Based on the combined anterograde tracing and immunohistochemical data, it is proposed that septal projections provide a direct innervation to habenular neurons that contain ChAT or SP activity. These septal inputs may play an important role in the facilitation of the ChAT- and SP-positive habenular neurons, both of which provide prominent afferent inputs to the interpeduncular nucleus. Thus, neurons of the habenula and interpeduncular nucleus are under the direct and indirect influence of septal neurons within the limbic forebrain circuit.

Comparison of synenkephalin and methionine enkephalin immunocytochemistry in rat brain

Immunocytochemistry using an antiserum to the C-terminal octapeptide of synenkephalin, proenkephalin(63-70), was performed throughout the rat brain and revealed numerous immunopositive fibers and some cell bodies. The morphology and distribution of synenkephalin immunoreactivity was extremely similar to that of a commercial methionine enkephalin (Met-ENK) antiserum. Colchicine pretreatment allowed the immunostaining of cell bodies not otherwise possible without pretreatment, but did not affect the distribution of immunoreactive fibers. Using 6 microns serial sections, we were able to colocalize synenkephalin and Met-ENK immunoreactivities in gigantocellular neurons of the medullary reticular formation. Preabsorption of the antiserum with [Tyr63]proenkephalin(63-70) octapeptide (YEESHLLA) completely eliminated immunoreactivity in the rat brain, while preabsorption with all other peptides used had no detectable effect. We conclude that our antiserum to synenkephalin is specific for enkephalinergic cell bodies, fibers and terminals. The synenkephalin antiserum used in these studies may have advantages over other antisera utilized for immunocytochemical detection of proenkephalin gene expression.

Existence of a GnRH immunoreactive nucleus in the dorsal midbrain tegmentum of the chameleon

The GnRH system of the chameleon brain was studied at light microscopic and ultrastructural levels by use of an immunohistochemical technique with antibodies directed against salmon gonadotrophin-releasing hormone. Immunoreactive (IR) perikarya were found in the anterior midbrain tegmentum. At this level numerous IR cell bodies were detected around the fasciculus longitudinalis medialis (FLM). The more rostral neurons were observed dorsal to the FLM and progressively tended to be lateral to it along the midline. More caudally, they were found ventral to the FLM. At the electron microscope level, these cells were seen to contain large granular vesicles and to receive numerous synaptic inputs. A prominent pathway was traced from these cell bodies along the medulla oblongata to the spinal cord. A second IR pathway ascended rostrally to the habenular complex. No IR perikarya were located in the anterior brain including the olfactory bulbs.

Somatostatin-containing neurons in the mouse brain: an immunohistochemical study and comparison with the rat brain

The distribution of somatostatin-containing neurons in mice of both sexes was immunohistochemically examined and compared with that in rats. In radioimmunoassay the relative somatostatin content in the mouse brain was 2-3 times higher than that in the rat. The overall immunohistochemical staining for somatostatin was much stronger and more prominent in the mouse than in the rat. 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. The electrolytic lesions to the nucleus anterior hypothalami caused a marked decrease in somatostatin immunoreactivity of the outer layer of the median eminence in the mouse. This suggests that the nucleus anterior hypothalami is an additional source of somatostatin for the median eminence in the mouse. The differences recognized between the species are interesting from functional and evolutionary points of view.

Distribution of serotonin 5-HT1C receptor mRNA in adult rat brain

Based on in situ hybridization histochemistry (ISHH), we describe the anatomical distribution of the serotonin 5-HT1C receptor mRNA. In addition to the very high levels in epithelial cells of the choroid plexus, 5-HT1C receptor mRNA is found throughout the limbic system, in catecholaminergic cells and in serotonergic neurons. Receptor transcripts are also present in the hypothalamus, numerous motor nuclei and the subthalamus. Our results correlate well with serotonin (5-HT) innervation and receptor binding. Receptor mRNA is present in many brain structures in addition to regions previously shown to have 5-HT1C receptor binding. The distribution of this receptor mRNA suggests that the 5-HT1C receptor may mediate a number of the central effects of 5-HT.

Distribution of serotonin in the brain of the mormyrid teleost Gnathonemus petersii

The distribution of serotonin-immunoreactive neurons and fibers was studied in the highly developed brain of the weakly electric fish Gnathonemus petersii with the aid of specific antibodies against serotonin. Serotoninergic cell bodies occur in three regions: the raphe region of the brainstem, the hypothalamus, and the transition zone between the dorsal thalamus and the pretectum. Serotoninergic raphe neurons are clustered in three groups: nucleus raphes superior, intermedius, and inferior. The latter has not been described in other teleosts and thus might be the source of the serotoninergic innervation of specific mormyrid electrosensory brain regions. Most hypothalamic serotoninergic neurons have cerebrospinal-fluid (CSF)-contacting processes and thus belong to the paraventricular organ (PVO), which in Gnathonemus is located around a number of small infundibular recesses. The distribution of serotonin in the PVO precisely matches the distribution of dopamine, as described previously. Serotoninergic cells in the thalamopretectal transition zone also have been described in other teleosts, but not in other vertebrate groups, and thus seem to represent a teleostean specialization. Serotoninergic fiber density is especially high in the medial forebrain bundle and surrounding preoptic and hypothalamic regions as well as in several telencephalic and preoptic subependymal plexus. Serotoninergic fibers appear to be almost completely absent in the large and differentiated corpus and valvula cerebelli. Comparison with the literature on teleostean serotoninergic innervation patterns reveals several mormyrid specializations, including the absence of serotonin in large parts of the mormyrid telencephalic lobes, a differentiated innervation pattern of distinct electrosensory and mechanosensory subnuclei of the torus semicircularis, a refined serotoninergic lamination pattern in the midbrain tectum, and a prominent innervation of the electrosensory lateral line lobe, the associated caudal cerebellar lobe, and the electromotor medullary relay nucleus. A distinct innervation of several types of (pre)motor neurons, such as the Mauthner cells and facial motor neurons, has not been reported previously for other teleosts. Consequently, the distribution of serotoninergic fibers as well as neurons in the mormyrid brain is substantially adapted to the high degree of differentiation of its electrosensory and telencephalic brain regions, but serotoninergic innervation is not involved in the circuitry of the most impressive part of the mormyrid brain; i.e., its large corpus and valvula cerebelli.

An immunoblot assay for the simultaneous quantification of several antigens

A radioimmunologic assay method that allows for the simultaneous quantification of several antigens in one sample is described. Polypeptide antigens are resolved electrophoretically and electroblotted to nitrocellulose. The nitrocellulose is then reacted with a mixture of several antisera simultaneously, and antibody-binding proteins are visualized by incubation with 125I-protein A and by autoradiography. Antigens are identified according to their molecular weights and quantified by counting the bound radioactivity. The sensitivity of the assay is in the low nanogram range and can be adjusted individually for each antigen by appropriately diluting the first antiserum. The procedure is presently applied to the detection of three neural antigens, neural cell adhesion molecule, neuron-specific enolase, and synaptophysin, in adult brain tissue and to the assessment of expression of the latter two during development of brain cells in primary culture. The method is fast, comparatively cheap, and associated with a low radiation exposure. It should prove especially useful when only scarce amounts of sample are available.

Immunohistochemical localization of intracellular plasma proteins in the human central nervous system

The regional distribution of plasma protein immunoreactivity was studied in the postmortem central nervous system (CNS) of normal subjects 18 to 78 years old. Samples taken from various areas of brain and spinal cord were processed for peroxidase-antiperoxidase immunocytochemistry using polyclonal antibodies against plasma albumin, prealbumin, alpha 1-acid glycoprotein, alpha 2-macroglobulin, IgG, transferrin, haptoglobin, hemopexin, fibrinogen, as well against the glial fibrillary acidic and S-100 proteins. Many neurons of the spinal cord, cranial nerve nuclei, pontine nuclei, cerebellar dentate nucleus, red nucleus, thalamus and hypothalamus showed strong immunostaining for albumin and moderate to strong staining for alpha 1-acid glycoprotein, IgG, transferrin, haptoglobin, as well as relatively weak immunoreactivity against other plasma proteins. Less intense staining was seen in the nucleus basalis, putamen and Purkinje cells. In contrast, most cerebral cortical neurons were negative except for a few positively stained pyramidal neurons in the hippocampus and in layers III and V of the association neocortex, although more positive pyramidal neurons were observed in the motor and sensory neocortices. Reaction products were also seen in axons of motor and sensory long tracts. These findings suggest that plasma proteins may be transported to spinal cord and brain stem neurons by peripherally projecting nerves and that a series of anterograde and retrograde transneuronal transfers are responsible for the accumulation of plasma proteins in relay nuclei and in other CNS neurons.

Characterization of thyrotropin-releasing hormone in the central nervous system of African lungfish

Central administration of thyrotropin-releasing hormone (TRH) produces potent effects on various physiological parameters, such as arousal, respiration, and cardiovascular function, in several species. As part of an investigation into the evolution of this tripeptide as a central modulator of these parameters, we examined its distribution in the central nervous system of the African lungfish (Protopterus). Lungfish brains were dissected into three regions: telencephalon, diencephalon, and medulla. Each region was assayed for TRH by radioimmunoassay and for norepinephrine, dopamine, and serotonin by HPLC/electrochemical methods. TRH immunoreactivity (IR-TRH) was present in all regions of lungfish brain examined. The telencephalon contained the highest concentrations of TRH, the diencephalon also contained a high concentration of TRH, and the medulla contained a markedly lower concentration. Similar concentration gradients (telencephalon greater than diencephalon greater than medulla) were observed for norepinephrine, dopamine, and serotonin. The identity of IR-TRH as authentic TRH was confirmed by elution profiles on HPLC. The results of this investigation demonstrated that TRH and the monoamine neurotransmitters are present in high concentrations in various regions of lungfish brain. The lungfish may represent a promising model for further studies of the interactions of TRH with these neurotransmitter systems.

Immunohistochemical studies on cholecystokinin (CCK)-immunoreactive neurons in the rat using sequence specific antisera and with special reference to the caudate nucleus and primary sensory neurons

In the present immunohistochemical study the occurrence and distribution of CCK-immunoreactive neurons were analyzed in the brain, spinal cord and sensory ganglia using sequence specific antisera. Thus, antibodies directed towards the C-terminal portion of CCK-33, to the N-terminal portion of CCK-8 and to the mid portion of CCK-33 as well as monoclonal antibodies were used. For comparison antisera raised against calcitonin gene-related peptide (CGRP), tyrosine hydroxylase (TH) and 5-hydroxytryptamine (5-HT) were used. Untreated, colchicine treated, 6-hydroxydopamine (6-OH-DA) treated and ibotenic acid treated rats were analyzed. The results indicate that most CCK systems in the rat central nervous system contain genuine CCK. These include, for example, the hippocampal formation, the hypothalamus, several subcortical forebrain areas, the ventral mesencephalon, nucleus tractus solitarii, some neurons in the ventral medulla oblongata as well as local and possibly descending neurons in the spinal cord. An exception was primary sensory neurons in which CCK-like immunoreactivity (LI) could only be demonstrated with C-terminally directed antisera and probably represents cross-reactivity with CGRP or a similar peptide. The central branches of such primary afferents were found both in the dorsal vagal complex, in the spinal trigeminal nucleus and in the dorsal horn of the spinal cord. Special attention was focused on CCK-LI in mesencephalic dopamine neurons and in their projection areas including nucleus accumbens, tuberculum olfactorium and particularly the caudate nucleus. In the latter structure CCK-LI exhibited a heterogenous pattern probably representing fibres of different types and origin. Thus, CCK-LI coexists with dopamine in two anatomically and morphologically distinguishable systems, one located in the periventricular area, increasing in size in the caudal direction to occupy most of the cauda, and a second system consisting of very fine dots in the medial half of the caudate nucleus. These two fibre types disappeared after 6-OH-DA treatment. A third system consisted of strongly fluorescent patches distributed at all levels of the caudate nucleus, mainly in its medial half. A diffuse, weakly fluorescent network of CCK-positive fibres was also found over the entire caudate nucleus. The latter two systems did not disappear after 6-OH-DA. Finally, local CCK-positive cell bodies were seen in small numbers, mainly in the ventral aspects of the caudate nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)

Immunocytochemical distribution of [Met]enkephalin-Arg-Gly-Leu immunoreactivity in the rat diencephalon

Recently, [Met]Enkephalin-Arg-Gly-Leu (MEAGL) was isolated from bovine adrenal glands, and it was found to be derived exclusively from proenkephalin. Therefore, we investigated the distribution of MEAGL-like immunoreactive neuronal perikarya and fibers in the rat diencephalon pretreated with colchicine by PAP immunocytochemistry. In the thalamus MEAGL immunoreactive neuronal perikarya were distributed in the paraventricular nucleus and the ventral part of the lateral geniculate nucleus. Immunoreactive fibers were found in the paraventricular, paracentral, anteroventral, reuniens and rhomboid nuclei. In addition, immunoreactive fibers were also noted in the anterior pretectal nucleus. In the hypothalamus, immunoreactive neuronal perikarya were observed in the medial preoptic area, anterior and lateral hypothalamic nuclei, perifornical region, parvocellular and postero-magnocellular regions of paraventricular nucleus, ventromedial nucleus, dorsomedial nucleus, arcuate nucleus, premammillary, medial mammillary and lateral mammillary nuclei. The distribution of immunoreactive fibers was similar to that of neuronal perikarya. However, immunoreactive fibers were also observed in the supraoptic and suprachiasmatic nuclei where no immunoreactive neuronal perikarya were detected. Numerous immunoreactive fibers were detected in the external layer of the median eminence, but there were few in the internal layer. The similarity and difference in the distribution between MEAGL and other proenkephalin peptides such as [Met]enkephalin were also discussed.

Immunocytochemical localization of serotonin-containing neurons in the myelencephalon, brainstem and diencephalon of the sheep

Using immunocytochemistry, morphological characteristics and distribution of serotonin-containing neurons and fibers of the sheep myelencephalon, brainstem and diencephalon were studied, employing highly specific antibodies to serotonin. The immunocytochemical procedure described here allowed the visualization of endogenous, and thus presumably physiological, pools of serotonin, because no pharmacological treatments (colchicine, inhibitors of monoamine oxidase or 5-hydroxytryptophan) were used to increase the endogenous amount of antigen. The distribution of serotonin cell bodies observed in the study is in agreement with that described by other authors in the rat using a similar method. The present work also shows more numerous groups than the formaldehyde-induced fluorescence method, because five additional groups were revealed, designated S1 to S5. Compared with those in the rat, sheep serotonergic structures exhibit striking specific characteristics: (1) greater scattering of cell bodies within the different groups visualized, (2) absence of group B4 and hypothalamic groups, (3) only a weak serotonergic innervation of the suprachiasmatic nuclei area.

Axon pathway boundaries in the developing brain. I. Cellular and molecular determinants that separate the optic and olfactory projections

When optic fibers first approach the chiasmatic region of the diencephalon in the chick embryo on days 3 and 4 (E3-4), they rarely grow rostrally into the olfactory region of the telencephalon. Conversely, olfactory tract axons grow as far as, but never cross the diencephalic/telencephalic (D/T) boundary to enter the optic chiasm. In this study, a region of specialized neuroepithelium, originally named the "knot" in mouse by Silver (1984), has been identified at the D/T border of chick embryos. At pre-axonal stages, the presumptive knot region undergoes a cataclysmic cell death, with concomitant phagocytosis of necrotic debris by the remaining cells. When fibers subsequently appear in the chiasm and olfactory tracts, the knot consists of a very dense, interwoven cluster of non-neuronal cells that lack marginal radial processes, and whose cell bodies directly abut the glial limiting membrane. Thus, the morphology of the knot is in sharp contrast to the cell body-free marginal zone and endfoot regions along which axons tend to grow. In addition, we found that the neural cell adhesion molecule (N-CAM), which is expressed on neuroepithelial cell processes within the central optic and olfactory pathways, is not present on cells in the knot region during periods of axon growth. These results suggest that the knot, through its elimination of the marginal zone processes, absence of large extracellular spaces, and relative absence of adhesion molecules, functions as an axon-refractory barrier that effectively separates the optic and olfactory projections.

Localization of thyrotropin-releasing hormone prohormone messenger ribonucleic acid in rat brain in situ hybridization

We studied the distribution of pro- TRH mRNA in rat brain by in situ hybridization histochemistry using radiolabeled single stranded cRNA probes to confirm the hypothesis that the TRH precursor is distributed beyond regions that contain immunoreactive TRH. All regions of the central nervous system previously recognized to contain TRH showed hybridization. Hypophysiotropic neurons in the medial parvocellular division of the paraventricular nucleus showed more intense hybridization than anterior parvocellular division cells, suggesting regional differences in expression. In addition, regions not previously recognized to contain TRH in neuronal perikarya by immunocytochemistry showed specific hybridization for pro-TRH mRNA. These include cells in the olfactory bulbs, dorsal motor nucleus of the vagus, ventrolateral periaqueductal gray, reticular nucleus of the thalamus, and anterior commissural nucleus. Only a single hybridizing band was observed on Northern blots of RNA extracts of the periaqueductal gray and reticular nucleus, identical to that seen in extracts of the paraventricular nucleus. The appearance of pro-TRH mRNA in neurons not previously recognized to contain TRH but which contain the prohormone suggests that non-TRH peptides within the TRH precursor may be preferentially expressed in certain regions of the brain.

Presence of glucocorticoid receptor immunoreactivity in corticotrophin releasing factor and in growth hormone releasing factor immunoreactive neurons of the rat di- and telencephalon

By means of the indirect immunoperoxidase technique using two-color immunocytochemistry a moderate to strong nuclear glucocorticoid receptor (GR) immunoreactivity was demonstrated in the vast majority of the corticotrophin-releasing factor (CRF)-immunoreactive nerve cells of the parvocellular parts of the paraventricular hypothalamic nucleus, of the septohypothalamic nucleus, of the bed nucleus striae terminalis and of the central and medial amygdaloid nuclei. All the growth hormone-releasing factor (GRF)-immunoreactive nerve cells of the lateral magnocellular part of the arcuate nucleus in its entire rostrocaudal extent showed a moderate GR immunoreactivity. These results and others indicate that glucocorticoids may directly affect all the CRF and GRF cell populations projecting into the median eminence as well as CRF and GRF neurons controlling behavioral and autonomic functions.

Distribution and morphology of vasopressin-, neurophysin II-, and oxytocin-immunoreactive cell bodies in the forebrain of the cat

Experiments were done to provide a detailed map of the location and a description of morphological characteristics of vasopressin (AVP-IR)-, neurophysin II (NII-IR)- and oxytocin (OXY-IR)-immunoreactive neuronal perikarya in the forebrain of the cat. In addition, the location of cells in the forebrain retrogradely labeled following injections of tracers into the neurohypophysis was determined. The distribution of AVP-IR and NII-IR was similar in all cases studied. Most of the cells containing AVP-IR and OXY-IR were observed in the hypothalamic paraventricular (PVH) and supraoptic (SON) nuclei. In addition, AVP-IR and OXY-IR cell bodies were found in the regions of the nucleus of the diagonal band of Broca, the dorsal chiasmatic nucleus, the anterior hypothalamic-preoptic area, the periventricular area, the nucleus circularis, the perifornical area of the lateral hypothalamus, the accessory SON, the area of the tuber cinereum (Tca), and the medial nucleus of the amygdala. The density of AVP-IR cells was greater than that of OXY-IR cells in these regions. Several forebrain areas were also observed to contain only AVP-IR perikarya: the suprachiasmatic nucleus (Sc), the bed nucleus of the stria terminalis, and the region of the substantia innominata and ventral globus pallidus (SI/GP). In addition, the dorsomedial nucleus of the hypothalamus only contained OXY-IR perikarya. Most of the cells immunoreactive to AVP were multipolar and had spinelike processes over their somata and proximal dendrites. In addition, the majority of cells in the PVH and SON were round or oval, whereas those outside these nuclei were fusiform or triangular. The mean somal area of AVP-IR cells in the region of the SI/GP was significantly (P less than 0.05) larger than that of AVP-IR cells in all other regions examined, whereas the mean somal area of Sc AVP-IR cells was significantly (P less than 0.05) smaller than that of all other groups of AVP-IR cells examined. Most OXY-IR cells were similar morphologically to those immunoreactive to AVP, except that OXY-IR cell bodies and their appendages did not have spinelike processes. In addition, OXY-IR perikarya were generally of uniform size. OXY-IR cells in the PVH and accessory SON were significantly (P less than 0.05) larger than AVP-IR cells in the same regions, but were not different from AVP-IR cells in the lateral hypothalamus and SON.(ABSTRACT TRUNCATED AT 400 WORDS)

Topography of cholinergic and substance P pathways in the habenulo-interpeduncular system of the rat. An immunocytochemical and microchemical approach

The topography of cholinergic and substance P containing habenulo-interpeduncular projections has been studied in the rat. The research has been carried out by combining choline acetyltransferase and substance P immunohistochemistry to experimental lesions and biochemical assays in microdissected brain areas. In addition, computer-assisted image analysis has been performed in order to obtain quantification of immunohistochemical data. The results show that cholinergic and substance P containing neurons have a different localization in the medial habenula and project to essentially different areas of the interpeduncular nucleus. Cholinergic neurons are crowded in the ventral two-thirds of the medial habenula while substance P containing cells are exclusively localized in the dorsal part of the nucleus. In most parts of the interpeduncular nucleus, choline acetyltransferase and substance P containing fibres and terminals are similarly segregated and no overlapping is apparent except for the rostralmost and the caudalmost ends of the nucleus. Cholinergic activity is largely concentrated in the central core of the nucleus, while substance P is preferentially localized in the peripheral subnuclei of the interpeduncular nucleus. In addition, both substance P and choline acetyltransferase levels show peculiar regional variations along the rostrocaudal axis of the interpeduncular nucleus. The results of experimental lesions demonstrate that the substance P projection carried by each fasciculus retroflexus is prevailingly ipsilateral in the rostral part of the interpeduncular nucleus and becomes progressively bilateral as far as more caudal regions of the nucleus are reached. By contrast, the cholinergic projections carried by each fasciculus retroflexus intermingle more rapidly and only show a slight ipsilateral dominance in the interpeduncular nucleus. The results of the study are discussed with reference to previous anatomical and neurochemical data which, in several instances, had given rise to discrepant interpretations.

Organization of atriopeptin-like immunoreactive neurons in the central nervous system of the rat

The atrial natriuretic peptide, atriopeptin, is a circulating hormone that plays an important role in the regulation of fluid and electrolyte homeostasis. Several recent studies have shown that atriopeptin-like immunoreactivity is present within the central nervous system as well as peripheral tissues. In the present report, we describe in detail the organization of atriopeptin-like immunoreactive (APir) perikarya and fibers in the central nervous system of the rat. The most prominent collection of APir perikarya was found in the hypothalamus, adjacent to the anteroventral tip of the third ventricle. Additional groups of APir perikarya were observed along the wall of the third ventricle and in the paraventricular and arcuate nuclei. Separate, smaller groups with distinctive morphology were seen in the lateral hypothalamic area, in the supra-mammillary, medial, and lateral mammillary nuclei, medial habenular nucleus, bed nucleus of the stria terminalis, and the central nucleus of the amygdala. In the pons and brain-stem, APir neurons were observed in the pedunculopontine and laterodorsal tegmental nuclei, as well as in the ventral tegmental area, Barrington's nucleus, the parabrachial nucleus, and the nucleus of the solitary tract. The densest terminal fields of APir fibers were found in the paraventricular nucleus of the hypothalamus, the bed nucleus of the stria terminalis, the median eminence, and the interpeduncular nucleus. The presence of atriopeptin immunoreactivity within the central nervous system suggests that atriopeptin may function as a central neuromediator. Potential functions of this candidate neuromediator deduced from its anatomical distribution are discussed, including the possibility that atriopeptin may function as both a central neuromediator and a systemic hormone in the regulation of the cardiovascular system.

The distribution of dopamine immunoreactivity in the forebrain and midbrain of the lizard Gekko gecko: an immunohistochemical study with antibodies against dopamine

The distribution of dopamine (DA) immunoreactivity in the forebrain and the midbrain of the lizard Gekko gecko was studied by using recently developed antibodies against DA. Dopamine-containing cells were found around the glomeruli of the olfactory bulb, in several parts of the periventricular hypothalamic nucleus, in the periventricular organ, the ependymal wall of the infundibular recess, the lateral hypothalamic area and the pretectal posterodorsal nucleus of the diencephalon, and in the ventral tegmental area, the substantia nigra, and the presumed reptilian equivalent of the mammalian A8 cell group of the mesencephalon. Dopaminergic fibers and terminals were observed throughout the whole brain, but particularly in the diencephalon and the telencephalon. The nucleus accumbens appears to have the most dense innervation, but also the striatum, amygdaloid complex, olfactory tubercle, septum, and dorsal ventricular ridge (especially its superficial zone) show numerous DA-containing fibers and terminals. Except for the lateral cortex, cortical areas are not densely innervated by DA fibers. In several respects DA distribution in the gekkonid brain differs from that in other reptiles studied. For instance, in the Gekko the dorsal ventricular ridge is densely innervated by DA fibers, whereas in turtles and crocodiles the same structure shows only weak catecholaminergic histofluorescence. When compared to the distribution of DA immunoreactivity in mammals, it appears that the DA system in the gekkonid telencephalon resembles the distribution of DA in the limbic forebrain and striatum of mammals. Whether these similarities in distribution of DA also imply similarities in function will be discussed.

The distribution pattern of adrenocorticotropin-like immunoreactivity in the cat central nervous system

The distribution pattern of adrenocorticotropin-like immunoreactivity (ACTH-LI) in cats using the avidin-biotin modification of an immunocytochemical method shows cell bodies containing ACTH-LI in the medial basal hypothalamus, especially in the infundibular nucleus. The fibers from these neurons extended beyond the hypothalamus, into the paraventricular nucleus of the thalamus, rostral amygdala, periaqueductal gray, locus coeruleus, parabrachial nucleus and medial nucleus of the nucleus tractus solitarius. The distribution pattern of the cell bodies and fibers containing ACTH-LI bears several similarities to that seen in rats. The pattern differs from that of rats in the fact that the termination in the amygdala is more extensive and that ACTH-LI was not observed in cell bodies in any location other than the medial basal hypothalamus.

Central beta-endorphin release and recovery after exposure to nitrous oxide in rats

To explore the hypothesis that nitrous oxide stimulates the beta-endorphin system in vivo, rats were exposed to nitrous oxide/oxygen at variable concentrations for one hour. beta-Endorphin concentration at sites along the neuraxis functionally involved with analgesia was elevated in nitrous oxide-exposed animals. The increase in beta-endorphin concentration was statistically significant at nitrous oxide concentrations of 60 and 80%. This elevation of beta-endorphin levels depended on the concentration of nitrous oxide delivered rather than on the duration of exposure. With cessation of nitrous oxide anesthesia, beta-endorphin concentration returned to control levels within 30 minutes.

Immunolocalization of the thyrotropin-releasing hormone prohormone in the rat central nervous system

The distribution of immunoreactive TRH prohormone in the rat central nervous system was studied by immunocytochemistry using an antiserum raised against a synthetic decapeptide hypothesized to represent a portion of the mammalian TRH precursor protein. Reaction product was identified in several regions of the brain in a distribution typical of that previously described for the tripeptide. In contrast to TRH, however, immunoreactive pro-TRH was largely confined to neuronal perikarya and only rarely seen in axons or axon terminals. In addition, immunoreactive pro-TRH was present in portions of the telencephalon and brainstem where TRH has not previously been described in neurons by immunocytochemistry. These studies indicate that in most regions of the brain the TRH prohormone is rapidly processed within the cell soma and not during axonal transport, and raise the possibility that in certain regions of the brain processing of the prohormone may be to non-TRH peptides, which may be of biological importance.

Accurate evaluation of 1,2-diacylglycerol in gerbil forebrain using HPLC and in situ freezing technique

Gerbil forebrains were frozen in situ to inactivate the tissues, and 1,2-diacylglycerols were first measured quantitatively by HPLC. Although 1,2-diacylglycerols were completely recovered from the HPLC column, the control amount of 1,2-diacylglycerol in gerbil forebrain was only 79.6 nmol/g wet weight, which is about one-fourth of that previously reported for gerbil brain inactivated by liquid N2 after decapitation instead of in situ freezing. The fatty acid composition of 1,2-diacylglycerols in gerbil forebrain was first reported and the control 1,2-diacylglycerols were richer in palmitic acid than in stearic acid or arachidonic acid, which is rather different from the data previously reported for mouse or rat brain obtained by decapitation and analyzed by traditional TLC methods. The amount of 1,2-diacylglycerol increased by 82.9% in gerbil forebrain during 5 min of ischemia induced by bilateral carotid ligation. Arachidonic acid and stearic acid were abundant in the 1,2-diacylglycerols produced by 5 min of ischemia. Thus we were able to obtain accurate values of the amount and the fatty acid composition of 1,2-diacylglycerols in gerbil forebrains using HPLC and in situ freezing technique.

Distribution of neuropeptide Y-like immunoreactivity in the rat central nervous system--II. Immunohistochemical analysis

The distribution of neuropeptide Y-like immunoreactivity in the rat brain and spinal cord was investigated by means of the peroxidase-antiperoxidase procedure of Sternberger using a rabbit anti-neuropeptide Y serum. A widespread distribution of immunostained cells and fibres was detected with moderate to large numbers of cells in the following regions: olfactory bulb, anterior olfactory nucleus, olfactory tubercle, striatum, nucleus accumbens, all parts of the neocortex and the corpus callosum, septum including the anterior hippocampal rudiment, ventral pallidum, horizontal limb of the diagonal band, amygdaloid complex. Ammon's horn, dentate gyrus, subiculum, pre- and parasubiculum, lateral thalamic nucleus (intergeniculate leaflet), bed nucleus of the stria terminalis, medial preoptic area, lateral hypothalamus, mediobasal hypothalamus, supramammillary nucleus, pericentral and external nuclei of the inferior colliculus, interpeduncular nucleus, periaqueductal central gray, locus coeruleus, dorsal tegmental nucleus of Gudden, lateral superior olive, lateral reticular nucleus, medial longitudinal fasciculus, prepositus hypoglossal nucleus, nucleus of the solitary tract and spinal nucleus of the trigeminal nerve. In the spinal cord cells were found in the substantia gelatinosa at all levels, the dorsolateral funiculus and dorsal gray commissure in lumbosacral cord. The pattern of staining was found to be similar to that observed with antisera to avian and bovine pancreatic polypeptide, but to differ in some respects from that observed with antisera to molluscan cardioexcitatory peptide. The presence of neuropeptide Y immunoreactive fibres in tracts such as the corpus callosum, anterior commissure, lateral olfactory tract, fimbria, medial corticohypothalamic tract, medial forebrain bundle, stria terminalis, dorsal periventricular bundle and other periventricular areas, indicated that in addition to the localisation of neuropeptide Y-like peptide(s) in interneurons in the forebrain, neuropeptide Y may be found in long neuronal pathways throughout the brain.

Quantitative distribution of galanin-like immunoreactivity in the rat central nervous system

Using an antiserum directed against synthetic galanin (GAL) a sensitive radioimmunoassay was developed. The antiserum interaction with GAL was characterized by displacement curve characteristics and high performance liquid chromatography. Besides the main GAL-immunoreactive peak several small peaks with GAL-like immunoreactivity were observed. No cross-reactivity of the GAL-antiserum with several other peptides was observed. GAL-like immunoreactivity was measured in 37 microdissected areas of the rat central nervous system. High concentrations (greater than 2000 fmol/mg protein) were observed in the amygdaloid nuclei, the septum, globus pallidus, bed nuclei of the stria terminalis, all hypothalamic nuclei, the superior colliculus, locus coeruleus, the nucleus of the solitary tract and the neurointermediate lobe of the pituitary. Moderate concentrations (1000-2000 fmol/mg protein) were observed in the hippocampus, the nucleus accumbens and nucleus of the diagonal tract, the caudate-putamen, the central gray, the nucleus, tract and substantia gelatinosa of the spinal trigeminal nerve. The results generally correlate with those previously published by immunocytochemistry. The widespread distribution of GAL-like immunoreactivity in the rat central nervous system suggests an involvement of GAL in a variety of brain functions.

Distribution of immunoreactive melanin-concentrating hormone in the central nervous system of the rat

The distribution of melanin-concentrating hormone-like immunoreactivity (MCH-LI) in 41 microdissected brain and spinal cord regions was determined using radioimmunoassay with antibodies to salmon MCH. The highest concentration of MCH-LI was detected just ventral to the zona incerta (subzona incerta) (2923.2 fmol/mg protein). Very high concentrations of MCH-LI (greater than 1000 fmol/mg protein) were detected also in the nucleus of the diagonal band, medial forebrain bundle, posterior hypothalamic nucleus and medial mammillary nucleus. High concentrations of the peptide (between 500-1000 fmol/mg protein) were measured in 11 brain regions, including bed nucleus of stria terminalis, paraventricular nucleus, anterior hypothalamic nucleus, median eminence, parabrachial nucleus. Moderate concentrations of MCH-LI (between 250-500 fmol/mg protein) were measured in 16 brain regions, such as frontal cortex, central amygdaloid nucleus, medial septum, periventricular nucleus (preoptic) and nucleus of the solitary tract. Low concentrations of MCH-LI (less than 250 fmol/mg protein) were measured in 9 brain regions such as cortical areas, hippocampus, caudate nucleus and substantia nigra. Cervical spinal cord and neurointermediate lobe of the pituitary gland contain low concentrations of the peptide.

Ultrastructural localization and afferent sources of substance P in the rat parabrachial region

The ultrastructural morphology and afferent sources of terminals containing substance P-like immunoreactivity were examined in the rat parabrachial region. In the first portion of the study, a polyclonal antiserum to substance P was localized in the ventrolateral parabrachial region using the peroxidase-antiperoxidase labeling technique combined with electron microscopy. The antiserum was tested for cross-reaction with substance P, physalaemin, substance K and neuromedins B, C and K. Cross-reactivity was most intense with substance P. However, substance K, neuromedin K and physalaemin also exhibited limited cross-reactions with the antiserum. In the ventrolateral parabrachial region of untreated adult animals, substance P-like immunoreactivity was localized in axon terminals containing numerous small (40-60 nm) clear vesicle and 1-3 large (90-120 nm) dense-core vesicles. At least 54% of the labeled terminals formed asymmetric synapses with unlabeled dendrites; and at least 30% of the recipient dendrites received more than one labeled axon terminal. In addition, the labeled terminals were associated less frequently with other unlabeled soma, axon terminals and blood vessels. In the second part of the study, we examined whether or not perikarya in various extrinsic regions contributed to the substance P-like immunoreactivity in axon terminals in the parabrachial region. Wheat-germ agglutinin conjugated horseradish peroxidase was injected unilaterally into the parabrachial region of adult rats two days prior to being killed and one day prior to intraventricular injection of colchicine (100 micrograms in 7.5 microliter saline) which enhanced the detection of immunoreactivity in perikarya. Sections were first processed by a tetramethylbenzidine reaction stabilized with cobalt-diaminobenzidine for demonstration of the transported peroxidase then were immunocytochemically labeled for substance P. Perikarya containing both the black granular retrograde labeling and brown peroxidase-immunoreactivity were found in the nuclei of the solitary tracts, the caudal ventrolateral reticular formation, the lateral dorsal tegmental nucleus and the paraventricular, dorsomedial and lateral hypothalamic nuclei. The projections were largely, but not exclusively, from perikarya located on the same side as the parabrachial injection. We conclude that substance P, or a closely related tachykinin, is a putative transmitter or modulator within a number of pathways to the parabrachial region and that these afferents act primarily through axodendritic synapses with intrinsic neurons.

Distribution of immunoreactive atrial natriuretic peptides in the central nervous system of the rat

The distribution of immunoreactive (ir) atrial natriuretic peptides (ANPs) in 47 microdissected brain and spinal cord regions of the rat was determined by radioimmunoassay. The highest concentrations of ir-ANPs exist in the paraventricular nucleus and median preoptic nucleus (580.9 and 558.0 fmol/mg protein, respectively). High concentrations of ir-ANP (greater than 300 fmol/mg protein) are present in the interpeduncular nucleus, preoptic and hypothalamic periventricular nuclei, median eminence and organum vasculosum of the lamina terminalis. Moderate concentrations of ir-ANPs (between 100 and 300 fmol/mg protein) are found in 16 brain regions such as the bed nucleus of the stria terminalis, nucleus of the diagonal band, most of the hypothalamic nuclei, central gray, locus coeruleus and parabrachial nuclei. Low levels of ir-ANPs (less than 100 fmol/mg protein) exist in 22 brain regions including cortical areas, amygdala, caudate nucleus, nucleus accumbens, hippocampus, supraoptic nucleus, subfornical organ, medial mammillary nucleus, substantia nigra, dorsal raphe nucleus, cerebellum, nucleus of the solitary tract and others. Cervical spinal cord and neurointermediate lobe of pituitary gland contain low levels of ir-ANPs.

Localization of cells containing LHRH-like mRNA in rat forebrain using in situ hybridization

Using in situ hybridization, we localized cells in the rat forebrain which contain mRNA that hybridizes with a radiolabeled, synthetic oligodeoxyribonucleotide (59-mer) complementary to human LHRH mRNA in the region which includes the coding sequence for the decapeptide. These brain areas have been shown previously to contain immunoreactive LHRH cell bodies.

The organization of serotonin-immunoreactive neuronal systems in the brain of the crested newt, Triturus cristatus carnifex Laur

The distribution of serotonin (5-HT) immunoreactive structures has been investigated in the brain of the crested newt by means of indirect immunofluorescence, and unlabeled antibody peroxidase-antiperoxidase-complex (PAP) or biotin-avidin-system (BAS) techniques. In the newt, the bulk of the serotoninergic system extends from the raphe region of the medulla oblongata, through the isthmus, toward the mesencephalic tegmentum, and is characterized by pyriform neurons mainly located in a subependymal position, close to the midline. Also in the caudal hypothalamus, in addition to some 5-HT-positive adenohypophysial cells, many immunoreactive CSF-contacting neurons are found lining the paraventricular organ and the nucleus infundibularis dorsalis. A rich serotoninergic innervation was observed in the preoptic area and in the habenular complex. Concerning the telencephalon, immunopositive nerve fibers are encountered in the dorsal pallium, primordium hippocampi, striatum and olfactory bulbs. The general organization of serotoninergic systems in the newt brain exhibit close similarities to that described in higher vertebrates.

Regional and subcellular calmodulin content of rat brain

Calmodulin contents of cortex, cerebellum, striatum, diencephalon, and medulla + pons and of subcellular fractions of each region were determined by radioimmunoassay. The diencephalon had the highest level of calmodulin (48.87 +/- 4.56 micrograms/mg protein), whereas medulla + pons had the lowest level (8.01 +/- 0.84 micrograms/mg protein). In all brain regions, the mitochondrial fraction was richest in calmodulin (from 71 to 227 micrograms/mg protein) whereas other areas contained from 6 to 66 micrograms/mg protein.

Distribution of immunoreactive metorphamide (adrenorphin) in discrete regions of the rat brain: comparison with Met-enkephalin-Arg6-Gly7-Leu8

The distribution of immunoreactive (ir)-metorphamide (adrenorphin) in 101 microdissected rat brain and spinal cord regions was determined using a highly specific radioimmunoassay. The highest concentration of metorphamide in brain was found in globus pallidus (280.1 fmol/mg protein). High concentrations of ir-metorphamide (greater than 120 fmol/mg protein) were found in 9 nuclei, including central amygdaloid nucleus, lateral preoptic area, anterior hypothalamic nucleus, hypothalamic paraventricular nucleus, interpeduncular nucleus, periaqueductal grey matter and nucleus of the solitary tract. Moderate concentrations of the peptide (between 60 and 120 fmol/mg protein) were found in 47 brain nuclei such as nucleus accumbens, bed nucleus of stria terminalis, several septal and amygdaloid nuclei, most of the hypothalamic nuclei, ventral tegmental area, red nucleus, raphe nuclei, lateral reticular nucleus, area postrema and others. Low concentrations or ir-metorphamide (less than 60 fmol/mg protein) were measured in 41 nuclei, e.g., cortical structures, hippocampus, caudate nucleus, thalamic nuclei, supraoptic nucleus, substantia nigra, vestibular nuclei, cerebellum (nuclei and cortex). The olfactory bulb has the lowest metorphamide concentration (5.8 fmol/mg protein). Spinal cord segments exhibit very low peptide concentrations.

Melatonin formation in different parts of the guinea-pig pineal complex as assessed over 24 hours

There is morphological evidence that the pineal gland is not a uniformly built organ but rather a complex. In the guinea-pig the gland is 6--7 mm in length and dumbbell-shaped, the proximal part coming into intimate contact with central commissural fibres. The aim of the present 24-hour study was to examine in male guinea-pigs whether the proximal, intermediate and distal areas of the gland are involved in melatonin formation and to compare their rhythmicities. Levels of melatonin in serum and the whole pineal gland as assessed by RIA show day/night ratios of 1 : 1.25 and 1 : 3.3, respectively. Serotonin N-acetyltransferase activity was found to exhibit ratios of 1 : 1.75 (Experiment I) and 1 : 4.4 (Experiment II). All three pineal regions are involved in melatonin formation, and to the same extent. Whether the rhythms in the different regions are identical could not be clarified as the curves obtained exhibited striking oscillations and the day/night differences were rather small. As the extrapineal portion of the habenular commissure was found to contain melatonin there is a possibility that melatonin may be taken up when the commissural fibres pass through the pineal parenchyma.

Angiotensinogen levels in the brain and cerebrospinal fluid of the genetically hypertensive rat

The present experiments were designed to document changes in the regional distribution of angiotensinogen in the rat brain with the development of hypertension in spontaneously hypertensive rats (SHR) relative to age-matched normotensive Wistar-Kyoto rats (WKY). Levels of angiotensinogen were measured in discrete brain nuclei and cerebrospinal fluid from rats at 4, 7, and 16 weeks of age and in cerebrospinal fluid obtained by cisternal puncture at 7 and 16 weeks. Age-dependent changes in angiotensinogen were found, with levels higher in both strains at 4 weeks of age compared with 7 or 16 weeks. In contrast, plasma levels of angiotensinogen were essentially the inverse of the brain levels, low at 4 weeks and higher at 7 and 16 weeks. Levels in a number of regions adjacent to the rostral third ventricle from the 4-week-old SHR (prehypertensive phase) were significantly elevated relative to the WKY (p less than 0.05), while levels in the amygdala and posterior hypothalamus were significantly lower in the SHR (p less than 0.05). In 7-week-old rats (evolving phase), levels in nine brain regions were significantly elevated in the SHR relative to the WKY and included the nucleus tractus solitarii (p less than 0.01). Unlike the prehypertensive and evolving phases, in 16-week-old rats (maintenance phase) only two brain areas, the nucleus of the diagonal band and the lateral hypothalamus, had significantly elevated levels in the SHR (p less than 0.05). Cerebrospinal fluid levels of angiotensinogen did not correlate well with brain levels of angiotensinogen.(ABSTRACT TRUNCATED AT 250 WORDS)

gamma-Aminobutyric acid metabolism and behavioral effects after intraventricular injection of spermine in chicks

Effects of intraventricularly injected spermine on behavior and electrocortical activity and gamma-aminobutyric acid (GABA) metabolism after a single dose of 1.13 mumol/animal were studied. Decrease in locomotor activity, sedation or sleep, and electrocortical synchronization that lasted approximately 2 h were observed. In addition spermine caused a significant increase in GABA content in diencephalon and brainstem, 30 min after administration. Concomitantly a significant increase of glutamate decarboxylase (GAD) activity was observed in cerebral hemispheres, diencephalon, and brainstem. Reduction in gamma-aminobutyrate: alpha-oxoglutarate amino-transferase (GABA-T) levels occurred in the diencephalon along with a significant increase of GABA-T in the brainstem. The present results demonstrate that spermine has the capacity to affect GABA metabolism and are in favor of the suggestion that endogenous polyamines may modulate GABAergic mechanisms.

Central somatostatin systems revealed with monoclonal antibodies

The distribution of central neurons displaying somatostatin immunoreactivity was studied using three monoclonal antibodies to cyclic somatostatin. The sensitive ABC immunoperoxidase technique was employed. A large number of positive cell groups including many previously undescribed populations were detected throughout the brain and spinal cord. Telencephalic somatostatin neurons included periglomerular cells in the olfactory bulb, mitral cells in the accessory olfactory bulb, and multipolar cells in the anterior olfactory nuclei, neocortex, amygdala, hippocampus, lateral septum, striatum, and nucleus accumbens. Within the hypothalamus, positive neurons were found in the periventricular, suprachiasmatic, and arcuate nuclei, and throughout the anterior and lateral hypothalamus. The entopeduncular nucleus and zona incerta contained many positive neurons, and the lateral habenula had a dense terminal field suggesting a pallidohabenula somatostatin pathway. Somatostatin neurons were also found in association with many sensory systems. Positive cells were present in the superior and inferior colliculi, the ventral cochlear nuclei, the ventral nucleus of the lateral lemniscus, nucleus cuneatus, nucleus gracilus, and the substantia gelatinosa. Various cerebellar circuits also displayed somatostatin immunoreactivity. Golgi cells throughout the cerebellar cortex were intensely stained, and some Purkinje cells in the paraflocculus also showed a positive reaction. Positive fibers were present in the granular layer and large varicose fibers were present in the inferior cerebellar peduncle. Many nuclei known to project to the cerebellum, including the nucleus reticularis tegmenti pontis, the medial accessory inferior olive, the nucleus prepositus hypoglossi, and many areas of the reticular formation contained positive neurons. These studies demonstrate that these new monoclonal antibodies are of great value for the study of central somatostatin systems. Previously described somatostatin systems are readily detected with these antibodies, and in addition, many otherwise unrecognized somatostatin cell groups have been discovered.

Development of methionine-enkephalin in microdissected areas of the rabbit brain

Microdissected areas of the rabbit brain were isolated at prenatal day E-29, postnatal days P-3, 7, 14, 21, 2 months and adults. Methionine-enkephalin (ME) was assayed by RIA and ME concentration [ME] was expressed relative to the protein content of the extracted brain tissues. In brain nuclei with important roles in respiratory control [ME] was higher in prenatal and early postnatal life than in adults. In contrast, the prenatal and early postnatal [ME] levels in other nuclei were lower than or equal to adult values. These data suggest an important and changing role for ME in respiratory control throughout development. Early high [ME] levels within brainstem respiratory control nuclei may contribute to the newborn's increased susceptibility to respiratory depression.

Distribution of immunoreactive Met-enkephalin-Arg6-Gly7-Leu8 and Leu-enkephalin in discrete regions of the rat brain

The distribution of immunoreactive (ir) leucine-enkephalin (LE) and ir-methionine-enkephalin-Arg-Gly-Leu (ME-RGL) in 101 microdissected rat brain and spinal cord regions was determined using specific and sensitive radioimmunoassays. The highest concentrations of LE and ME-RGL were measured in globus pallidus (5190 and 4378.8 fmol/mg protein, respectively). Very high concentrations of LE and ME-RGL (greater than 750 fmol/mg protein) were found in the central amygdaloid nucleus, anterior hypothalamic nucleus, lateral preoptic area, nucleus of the solitary tract (medial and commissural parts), bed nucleus of stria terminalis, dorsomedial nucleus, parabrachial nuclei, periaqueductal gray and motor hypoglossal nucleus. Very high concentrations of ME-RGL were found in 14 additional brain regions including medial preoptic area, area postrema, nucleus ambiguus, periventricular nucleus, ventromedial nucleus, interpeduncular nucleus, paraventricular, arcuate and others. High concentrations of LE (between 500 and 750 fmol/mg protein) were found in 15 brain areas, among them the periventricular nucleus, medial preoptic area, suprachiasmatic nucleus, dorsal premamillary nucleus, ventromedial nucleus, arcuate nucleus, nucleus ambiguus, locus coeruleus, substantia nigra. High concentrations of ME-RGL were measured in 13 brain areas including the suprachiasmatic nucleus, lateral septal nucleus, raphe magnus, motor facial nucleus, lateral amygdaloid nucleus, sensory trigeminal nucleus, nucleus accumbens, caudate-putamen. Moderate concentrations of LE (between 250 and 500 fmol/mg) were found in 46 brain areas such as the lateral septal nucleus, nucleus accumbens, caudate-putamen, several amygdaloid nuclei, supraoptic nucleus, the perifornical nucleus, posterior hypothalamic nucleus, red nucleus. Moderate concentrations of ME-RGL were detected in 27 areas such as the median eminence, nuclei of the reticular formation, supraoptic nucleus, red nucleus and others.(ABSTRACT TRUNCATED AT 250 WORDS)

[Homovanillic acid levels in corpus striatum, limbic system and diencephalon of male and female rats]

The HVA levels in corpus striatum, limbic system and diencephalon in male and female rats during the postnatal period have been measured. The HVA levels in corpus striatum and diencephalon differed significantly when both sexes wee compared, whereas in limbic system significant differences were not found. A decrease in the levels of HVA in all areas studied was observed.

Ion-exchange chromatographic assay of peptidases acting on the C-terminal hexapeptide sequence of substance P

A rapid and sensitive assay for peptidases acting on the C-terminal hexapeptide sequence of the neuropeptide substance P is described. The radiolabelled substrate, N alpha-[125I]desaminotyrosyl-substance P (6-11) is easily prepared by coupling commercially available radioiodinated Bolton-Hunter reagent with substance P (6-11). Peptidase activity is determined by quantitative separation of the degradation products from the intact substrate on small QAE-Sephadex columns. The assay has been used to measure degradation of the substrate by rat parotid and diencephalon slices. The peptidase activity in the latter system was inhibited by substance P and substance P fragments and was sensitive to metal chelators and thiol reagents.

Topographical atlas of the gangliosides of the adult human brain

Forty different brain samples, consisting of neocortical, archicortical, and paleocortical areas; telencephalic, diencephalic, and mesencephalic subcortical nuclei; and the cerebellum as well as some of the corresponding white matter bundles were analyzed with respect to total content of ganglioside-sialic acid and the ganglioside pattern. The total content of gangliosides seems to depend mainly on the proportions of gray and white matter. Thus, neocortical areas, which are rich in gray matter, have a four- to fivefold higher ganglioside content (per milligram of protein) than white matter-rich samples such as optic chiasm, capsula interna, or corpus callosum. White matter-rich regions, although very heterogeneous in ganglioside composition, are further characterized by appreciable amounts of the myelin-enriched GM4. In the neocortex a remarkable degree of regional pattern differences was revealed. In the frontal and parietal areas there is a moderate, and in the temporal region a strong preponderance of sialic acid bound to gangliosides of the a-pathway (GD1a, GM1). In contrast, the occipital cortex favors the b-pathway of ganglioside synthesis (GQ1b, GT1b, GD1b). A predominance of "b-gangliosides" was found in all structures that are related to the visual system (optic chiasm, pulvinar-thalamus, superior colliculi, visual cortex) as well as in the cerebellum and the nucleus ruber. All diencephalic nuclei tend to favor slightly "b-gangliosides," while the mesencephalic nuclei are very heterogeneous in their ganglioside composition. A preponderance of "a-gangliosides" was found in the periamygdalar cortex, putamen, inferior colliculi, substantia nigra, frontal white matter, internal capsule, globus pallidus, basal nucleus of Meynert, and corpus callosum as well as in the frontal, parietal, and temporal cortices. An exceptional predominance of GM1 and GD1a was revealed for the hippocampal archicortex and the amygdala, suggesting a possible functional correlation to glutaminergic synaptic transmission.

Sex differences in gamma-aminobutyric acid and glutamate concentrations in discrete rat brain nuclei

gamma-Aminobutyric acid (GABA) and glutamate concentrations were measured in discrete brain nuclei in adult male and female rats. Significant sex differences in GABA and glutamate concentrations were found in the medical preoptic area (MPA) and ventromedial hypothalamic area (VMH) as well as the lateral hypothalamus, habenula and diagonal band for glutamate. Significant differences in GABA and glutamate concentrations were also observed throughout the estrous cycle in several brain areas. These results suggest that these neuronal systems are sexually differentiated as well as involved in the expression of gonadal steroid feedback.

Developmental changes in the amount of glial fibrillary acidic protein in three regions of the rat brain

Glial fibrillary acidic (GFA) protein, extractable in 50 mM phosphate buffer, pH 8, was measured in the olfactory bulbs, forebrain and cerebellum of the rat during development using a double antibody radioimmunoassay. Each brain region showed a different pattern of development for GFA protein. At birth GFA protein per mg protein was highest in olfactory bulbs followed by forebrain and cerebellum, and these amounted to 15, 10 and 8% of the adult values, respectively. The relative increase in GFA protein was more marked during the first 2 postnatal weeks than in the following 7 weeks after birth. When values were expressed per brain region, the developmental increase in the amount of GFA protein from birth to adulthood was about 100-fold in olfactory bulbs, 85-fold in forebrain and 485-fold in cerebellum. The patterns of developmental increases in GFA protein and in glutamine synthetase activity, another protein enriched in astrocytes, were similar in the forebrain and olfactory bulbs, but differed markedly in the cerebellum. The major increase in content of the GFA protein during development was found to correspond with the maturation of astrocytes rather than with their proliferation; however, a small but significant amount of GFA protein acquired at an early age may be related to increase in astroglial cell numbers in the cerebellum.

Ontogeny of a novel peptide, neuropeptide Y (NPY) in rat brain

Changes in the concentration of a newly discovered peptide, neuropeptide Y (NPY) have been determined in the developing rat brain using a recently developed radioimmunoassay and chromatographic analysis. NPY was present in the brain stem (14.8 +/- 5.6 pmol/g) and diencephalon (12.1 +/- 12.1 pmol/g) in the earliest embryos studied (14 days postconception), but appeared only on the 19th day postconception in the cerebral cortex. The concentrations of NPY showed a rapid postnatal rise in all regions examined. The finding of NPY early in the development of the embryonic rat brain and particularly in caudal regions has some similarities to the pattern of development of the catecholaminergic system.

Distribution of immunoreactive dynorphin B in discrete areas of the rat brain and spinal cord

The distribution of immunoreactive (ir)-dynorphin B in 101 microdissected rat brain and spinal cord regions was determined using a specific radioimmunoassay. The highest concentration of dynorphin B in brain was found in the substantia nigra (1106.2 fmol/mg protein). Very high concentrations of ir-dynorphin B (greater than 400 fmol/mg protein) were also found in the lateral preoptic area, parabrachial nuclei and globus pallidus. Relatively high concentrations of ir-dynorphin B (250-400 fmol/mg protein) were found in 19 nuclei, including the periaqueductal gray matter, anterior hypothalamic nucleus, median eminence, nucleus accumbens and hippocampus. Moderate levels of the peptide (between 100 and 250 fmol/mg protein) were found in 42 brain nuclei such as the perifornical nucleus, nucleus of the diagonal band, medial forebrain bundle, and dorsal premamillary nucleus. Low concentrations of ir-dynorphin B (less than 100 fmol/mg protein) were found in 28 brain areas, e.g. cerebral cortical structures (parietal, cingulate, frontal), claustrum, olfactory bulb, lateral and periventricular thalamic nuclei. The cerebellar cortex has the lowest dynorphin B concentration (53.7 fmol/mg protein). Spinal cord segments exhibit low or moderate (cervical segment) levels of the peptide. The neurointermediate lobe of the pituitary gland is extremely rich in ir-dynorphin B (11,047.1 fmol/mg protein).

Local changes in cerebral 2-deoxyglucose uptake during alphaxalone anaesthesia with special reference to the habenulo-interpeduncular system

The effects of the steroid anaesthetic Althesin (alphaxalone plus alphadolone acetate) on regional cerebral metabolism was studied in female rats. [14C]2-Deoxyglucose (2-DG) uptake was measured in 19 discrete anatomical areas by quantitative autoradiography. Under Althesin anaesthesia metabolic activity, relative to the corpus callosum ( rma ), was significantly (24-46%) increased in the locus coeruleus, medial (but not lateral) habenula (Hb) and interpeduncular nucleus (IPN). The Hb-IPN tract, not discernible in autoradiograms from conscious rats, became readily apparent in films from anaesthetized rats. However, the increased metabolic activity of this pathway was not associated with a significant change in the tissue concentrations of substance P in either the Hb or IPN. In sensorimotor and visual cortex, caudate nucleus, thalamic nuclei and the medial geniculate body rma was significantly (26-38%) depressed. Metabolic activity in the other 8 areas measured was unaffected by Althesin. Destruction of the stria medullaris input to the habenulae prevented the Althesin-induced increase in 2-DG uptake by the MHb and LHb.