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.

Mammalian telencephalic neurons express a segment-specific membrane glycoprotein, telencephalin

Using affinity chromatography with the monoclonal antibody 271A6, which binds selectively to telencephalic regions of the rabbit brain, we have purified a telencephalon-specific antigen to apparent homogeneity and characterized it as a membrane glycoprotein. The telencephalon-specific membrane protein (named "telencephalin") has a molecular weight of about 500,000 and is composed of four subunits each of mol. wt 130,000. Its digestion with N-glycanase reduced the subunit mol. wt by 23,000, indicating that each subunit has several N-asparagine-linked oligosaccharide chains. Immunohistochemical analysis using polyclonal antibody against the purified telencephalin shows that expression of the entire protein is restricted to the telencephalon. In addition, segment-specific expression of telencephalin was observed in all mammalian species examined (mouse, rat, guinea-pig, rabbit, cat and monkey). The telencephalon is the most rostral segment of the brain, and comprises the cerebral neocortex, paleocortex, hippocampus, septum, striatum and olfactory bulb. The present results indicate that all regions of the mammalian telencephalon express the segment-specific membrane glycoprotein, telencephalin, and suggest that telecephalin is involved in functions specific to the surface membrane of telencephalic neurons.

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.

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.

Ontogenesis of alpha 2-adrenoceptor coupling with GTP-binding proteins in the rat telencephalon

The ontogenesis of alpha 2-adrenoceptors and GTP-binding proteins and their coupling activity were investigated in telencephalon membranes of developing rats. The manganese-induced elevation of [3H]clonidine binding was increased in an age-dependent manner but the guanosine 5'-O-(3-thio)triphosphate-induced decrease in binding did not change. The extent of the binding of [3H]clonidine at 15 nM (saturable concentration) increased in an age-dependent manner and reached the adult level at 4 days after birth. Cholera toxin and pertussis toxin catalyzed ADP-ribosylation of proteins of 46 and 41/39 kilodaltons (kDa) in solubilized cholate extracts of the membranes. The 41/39-kDa proteins ADP-ribosylated by pertussis toxin (Gi alpha + Go alpha) were increased with age and reached the adult level at day 12, whereas the 46-kDa protein (Gs alpha) reached its peak on day 12 and then decreased to the fetal level at the adult stage. The immunoblot experiments of the homogenates with antiserum (specific antibody against alpha- and beta-subunit of GTP-binding proteins) demonstrated that the 39-kDa alpha-subunit of (Go alpha) and the 36-kDa beta-subunit of GTP-binding protein (beta 36) increased with postnatal age. In contrast, 35-kDa beta-subunit (beta 35) did not change. From these results, it is suggested that the coupling activity of alpha 2-adrenoceptor with GTP-binding protein gradually develops in a manner parallel with the increase of alpha 2-adrenoceptor and pertussis toxin sensitive GTP-binding proteins, Gi, and that alpha 39 beta 36 gamma may be related to the differentiation and/or growth of nerve cells in rat telencephalon.

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.

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.

A fibronectin-like molecule is present in the developing cat cerebral cortex and is correlated with subplate neurons

The subplate is a transient zone of the developing cerebral cortex through which postmitotic neurons migrate and growing axons elongate en route to their adult positions within the cortical plate. To learn more about the cellular interactions that occur in this zone, we have examined whether fibronectins (FNs), a family of molecules known to promote migration and elongation in other systems, are present during the fetal and postnatal development of the cat's cerebral cortex. Three different anti-FN antisera recognized a single broad band with an apparent molecular mass of 200-250 kD in antigen-transfer analyses (reducing conditions) of plasma-depleted (perfused) whole fetal brain or synaptosome preparations, indicating that FNs are present at these ages. This band can be detected as early as 1 mo before birth at embryonic day 39. Immunohistochemical examination of the developing cerebral cortex from animals between embryonic day 46 and postnatal day 7 using any of the three antisera revealed that FN-like immunoreactivity is restricted to the subplate and the marginal zones, and is not found in the cortical plate. As these zones mature into their adult counterparts (the white matter and layer 1 of the cerebral cortex), immunostaining gradually disappears and is not detectable by postnatal day 70. Previous studies have shown that the subplate and marginal zones contain a special, transient population of neurons (Chun, J. J. M., M. J. Nakamura, and C. J. Shatz. 1987. Nature (Lond.). 325:617-620). The FN-like immunostaining in the subplate and marginal zone is closely associated with these neurons, and some of the immunostaining delineates them. Moreover, the postnatal disappearance of FN-like immunostaining from the subplate is correlated spatially and temporally with the disappearance of the subplate neurons. When subplate neurons are killed by neurotoxins, FN-like immunostaining is depleted in the lesioned area. These observations show that an FN-like molecule is present transiently in the subplate of the developing cerebral cortex and, further, is spatially and temporally correlated with the transient subplate neurons. The presence of FNs within this zone, but not in the cortical plate, suggests that the extracellular milieu of the subplate mediates a unique set of interactions required for the development of the cerebral cortex.

Immunocytochemical localization of vasoactive intestinal polypeptide (VIP) in the brain of the little brown bat (Myotis lucifugus)

Vasoactive intestinal polypeptide (VIP)-like immunoreactivity has been examined in the brain of the little brown bat, Myotis lucifugus, using light microscopic immunocytochemistry and the indirect antibody enzyme method of Sternberger. Animals were sacrificed at three different and discrete levels of physiological activity: euthermic, hypothermic and hibernating. The density and distribution of immunoreactive neurons and fibres was compared in the three animal groups with the aid of a computerized image analysis system. Our results were compared with those of previous studies in laboratory species such as the rat and cat. Our study has demonstrated marked changes in the density of VIP-immunoreactive fibres and plexuses in the anterior hypothalamic area which correspond to the physiological state of the animal. In addition we have demonstrated the presence of VIP immunoreactive perikarya in a number of previously unreported locations. These include the paraventricular and periventricular hypothalamic nuclei, the linear raphe nucleus, nucleus interfascicularis, and in neurons embedded in the fibres of the dorsal tegmental decussation.

A developmentally regulated antigen associated with neural cell and process migration

The distribution of an epitope recognized by the monoclonal antibody JONES has been studied immunohistochemically in the developing nervous system of the rat. In the present report, we survey selected regions of the fetal, postnatal, and adult rat nervous system to test the hypothesis that JONES binding is invariably associated with neural cell migration and axon growth in the developing rat. A series of selected developmental stages extending from embryonic day (E) 9 to adult were used in this investigation. The distribution of JONES binding was examined using indirect immunofluorescence, as well as the immunogold procedure. Particular attention was paid to regions where the positions and timing of cell and axon migrations have been well described for the rat. JONES immunoreactivity first appears at E11-12, when it is localized to the lamina terminalis, the telencephalic-diencephalic junction, the midbrain, and the rhombic lip regions of the cytologically undifferentiated neural tube. In all the regions studied, during embryonic and early postnatal life, the labeling is very intense in the ventricular zone and shows a radial array in the adjacent intermediate and marginal zones. The expression of JONES epitope correlates particularly with times of cell migration in the retina, superior colliculus, cerebellum, and telencephalon and in regions undergoing neurite extension, such as the developing optic tract, the white matter of the cerebellum, the dorsal roots, the trigeminal system, and olfactory nerve. JONES binding becomes progressively restricted in the postnatal period. In the adult brain, immunoreactivity is present only in the retina and cerebellum. In the retina, JONES labeling is present in the outer plexiform layer and optic fiber layer. The labeling in the optic fiber layer extends to the optic nerve head and stops abruptly outside the orbit. In the cerebellum, JONES shows a radially oriented pattern throughout the molecular layer and delineates the cell bodies in the Purkinje cell layer. The only non-neural regions that show JONES immunoreactivity are the adrenal medulla and the kidney glomeruli. We conclude that the antigens recognized by the JONES monoclonal antibody are associated with the migration of subsets of cells and axons within the developing rat nervous system and, consequently, may play a role in conveying selectivity to these processes.

GABA concentrations in forebrain areas of suicide victims

Concentrations of GABA and seven other amino acids, including the neurotransmitters or neuromodulators taurine, glycine, aspartate, and glutamate, were determined in postmortem brain samples from suicide victims and normal controls. The five brain areas (caudate nucleus, nucleus accumbens, frontal cortex, amygdala, and hypothalamus) contained very similar concentrations of the amino acids in both groups. The only significant difference between the groups was a low glutamine concentration in the hypothalamus of suicide victims. Even when the data were adjusted for differences in tryptophan concentration, a putative biochemical index for agonal and postmortem changes of brain tissue, no new differences emerged in the concentrations of neuroactive amino acids between suicide victims and control subjects.

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)

GABAergic structures in the chick telencephalon: GABA immunocytochemistry combined with light and electron microscope autoradiography, and Golgi impregnation

The distribution of gamma-aminobutyric acid (GABA)-ergic elements in 3 forebrain regions (medial mid-telencephalic hyperstriatum ventrale; paleostriatum augmentatum; lobus parolfactorius) of two-day-old domestic chicks was investigated using (1) light and electron microscope autoradiography following [3H]GABA uptake in vitro in combination with pre-embedding GABA immunocytochemistry and (2) Golgi impregnation and 'gold-toning' combined with postembedding GABA immunocytochemistry. In both the paleostriatal regions and the medial (mid-telencephalic) hyperstriatum ventrale, GABA immunolabelling was demonstrated with the pre-embedding technique. Radiolabelling with [3H]GABA was also shown in these regions, co-localised in many cases with the immunolabelling. In the paleostriatal regions, the majority of perikaryal labelling was found in ovoid, elongated or fusiform cell bodies of 6-7 micron diameter whereas in the medial (mid-telencephalic) hyperstriatum ventrale, larger (10-15 micron) multipolar and smaller (5-6 micron) bipolar neurons were found labelled. In the latter region, Golgi impregnated neurons of similar morphology were found to be immunopositive to GABA using the postembedding technique. The ultrastructure of [3H]GABA accumulating cells is characterised by pale or moderately granular nuclei with small invaginations, few mitochondria and a prominent Golgi apparatus. Astrocytes and ependymal cells are also labelled with [3H]GABA. GABA-labelled axon terminals represent 29-36% of the total in the 3 brain regions studied. They appear as electron-lucent boutons with few and often scattered synaptic vesicles and in most cases they form symmetrical axo-dendritic junctions.

Somatostatin and neuropeptide Y are almost exclusively found in the same neurons in the telencephalon of turtles

In mammals, somatostatin and neuropeptide Y (NPY) are largely found in the same neurons of the telencephalon. To determine if this is a phylogenetically ancient feature of telencephalic organization, the brain of red-eared turtles was examined using immunofluorescence double-labeling procedures. The results showed that somatostatin and NPY are found almost exclusively in the same neurons in the telencephalon of turtles, but these neuropeptides rarely co-occur in neurons outside the telencephalon. Thus, the extensive co-occurrence of NPY and somatostatin appears to be a feature of telencephalic organization that was present in the reptilian common ancestors of mammals and modern reptiles.

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)

Acetylation of synaptosomal protein: effect of Na+

In a previous study it was shown that the acetyl moiety can be incorporated into the protein of purified synaptosomes (1). This process was inhibited by veratridine and the inhibitory effect was counteracted by tetrodotoxin. This suggested that the flux of Na+ may be related to the acetylation process. We now report that in a sodium free medium the amount of acetylation is increased and the inhibitory effect of veratridine (veratrine) is no longer evident. The addition of Na+ leads to a decrease in acetylation in the presence of veratrine. The presence of scorpion toxin has an effect similar to that of veratrine and the two are not additive. Hence, they appear to act on a common site. Molecular sieve chromatography shows four radioactively labeled peaks, two of which are particularly affected by veratrine. We also show that [3H]acetate incorporated into synaptosomal protein can be recovered as acetyldansylhydrazide. In addition, the concentration of free and bound acetate was measured in whole brain as well as in synaptosomes.

Adrenalectomy-induced enhancement of CRF and vasopressin immunoreactivity in parvocellular neurosecretory neurons: anatomic, peptide, and steroid specificity

Following adrenalectomy (ADX), corticotropin-releasing factor (CRF) and vasopressin immunoreactivity are jointly expressed by a population of parvocellular neurosecretory neurons in the paraventricular nucleus of the hypothalamus (PVH). Because these cells stain positively for CRF, but not for vasopressin, after pretreatment with colchicine, the results suggest the existence of state-dependent alterations in the expression of peptides by neuroendocrine neurons. The present study sought to determine whether other neuropeptides (e.g., neurotensin, met-enkephalin) that have been colocalized with CRF in the parvocellular division of the PVH are influenced similarly by ADX; whether the enhancement of CRF and/or vasopressin immunoreactivity after ADX is limited to neurons of the PVH; and what factors might be involved in the regulation of the expression of these peptides in the PVH. The results confirmed that CRF and vasopressin immunoreactivity are both enhanced, and may be colocalized in a substantial population of parvocellular neurosecretory neurons after ADX; no comparable enhancement of staining for met-enkephalin or neurotensin was observed. The effect of ADX on CRF immunoreactivity was not limited to cells in the PVH, as neurons in the cerebral cortex, amygdala, and the bed nucleus of the stria terminalis also showed heightened CRF immunostaining after ADX; vasopressin immunoreactivity was never colocalized with CRF in these extrahypothalamic sites. Hypophysectomy produced an enhancement of CRF and vasopressin staining in the PVH that was comparable to that seen after ADX, implicating adrenal steroids as primary regulators of peptide expression in this system. Corticosteroid replacement studies in ADX rats indicated that lower doses of dexamethasone attenuated, and higher doses essentially abolished, the expected enhancement of both CRF and vasopressin immunoreactivity after ADX. The relative potency of steroids in mitigating these effects was dexamethasone greater than corticosterone greater than deoxycorticosterone greater than aldosterone. Collectively, these results indicate that the ADX-induced enhancement of CRF and vasopressin immunoreactivity in parvocellular neurosecretory neurons is at least somewhat specific to these peptides and to this cell type. Both peptides would appear to be regulated similarly by adrenal steroids, with glucocorticoids playing a primary role.

Effects of short-term lithium administration on tryptophan levels and 5-hydroxytryptamine synthesis in whole brain and brain regions in rats

The effects of short-term lithium administration on tryptophan levels and 5-hydroxytryptamine (5-HT) synthesis in whole brain and brain regions in rats were studied. Short-term lithium administration was found to increase whole brain tryptophan levels without affecting whole brain 5-HT synthesis. However, the increase of tryptophan varied between various brain regions, which may possibly be due to differences in the synaptosomal uptake of tryptophan between brain regions. In the striatum, where the tryptophan increase was most pronounced, an increase in 5-HT synthesis was found too. These latter findings suggest that the increase in 5-HT synthesis might be due to an increase in tryptophan availability.

An immunohistochemical study of the telencephalon of the African lungfish, Protopterus annectens

The telencephalon of the African lungfish, Protopterus annectens, was studied by immunohistochemical techniques in order to identify the major subdivisions of the telencephalon and determine the possible homologues of these subdivisions, if any, in other vertebrates. The distributions of four different neuropeptides (substance P, leucine-enkephalin, avian pancreatic polypeptide, and LANT6), a neurotransmitter (serotonin), and a neurotransmitter-related enzyme that is involved in catecholamine synthesis (tyrosine hydroxylase) were examined. The resultant labeling patterns indicated that the telencephalon of lungfish consists of three major subdivisions--a rostrally and dorsally situated olfactory bulb, a dorsally situated pallial region located caudal to the olfactory bulbs, and a ventrally situated subpallial regions. The dorsal and lateral pallial regions, which both receive secondary olfactory input, are somewhat distinct from one another cytoarchitectonically, but their immunohistochemical labeling characteristics did not differ. Thus, the lateral pallium and the dorsal pallium together appear to constitute an olfactory pallium in lungfishes. The medial pallium was found to consist of three immunohistochemically distinct subdivisions--a dorsal cell group, an intermediate cell group, and a ventral cell group. These medial pallial fields extend throughout the entire rostrocaudal extent of the medial wall of the telencephalon. Although one or more of these medial pallial cell groups may be homologous to specific portions of the medial pallium in land vertebrates, no specific similarities were observed to support any proposed one-to-one correspondences. The possibility that one or more of the medial pallial cell groups of lungfishes correspond to cell groups located in the dorsal pallium of land vertebrates could not be excluded. The subpallium is divided into lateral, medial, and caudal subdivisions. The lateral subdivision appears to be homologous to the basal ganglia of land vertebrates since it contains neuropeptide/neurotransmitter-specific neuronal populations that are characteristic of the striatal and pallidal portions of the basal ganglia of amniotes. The medial subdivision of the subpallium shows the topographic and immunohistochemical characteristics of the septal region and the nucleus accumbens region of the amniote telencephalon. The caudal subpallium does not show any distinctive immunohistochemical labeling characteristics and its possible homologue in land vertebrates is unclear.(ABSTRACT TRUNCATED AT 400 WORDS)

Zinc accumulation in the telencephalon of lizards

The zinc concentration in the brains of two species of lizard was determined by atomic-absorption spectrophotometry. The zinc concentration was found to be highest in the telencephalon of Lacerta galloti (21.1 micrograms/g fresh weight) and Podarcis hispanica (16.77 +/- 0.8 micrograms/g) while the mesencephalon and brain stem exhibited lower zinc concentrations, i.e., 7.0 micrograms/g in Lacerta galloti and 6.08 +/- 0.4 micrograms/g in Podarcis hispanica. This high telencephalic concentration of zinc is paralleled by intense and well-defined Timm reactivity used for demonstrating the presence of zinc-containing boutons at the light-microscope level. Volumetric-densitometric studies of these Timm-reactive zones were performed using serial transverse sections of the same lizard brains.

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.

Telencephalic afferent nuclei in the carp diencephalon, with special reference to fiber connections of the nucleus preglomerulosus pars lateralis

Fiber connections of the nucleus preglomerulosus pars lateralis (PGl), which primarily provides afferent inputs to the telencephalon, were examined in carp by means of horseradish peroxidase tracing methods. The major afferent sources of PGl are the bilateral nucleus tuberis anterior and a few projections are found deriving from the ipsilateral nucleus ventromedialis thalami, nucleus centralis posterior, dorsal periventricular hypothalamus, and torus semicircularis. Axons arising in the PGl can be traced to the area dorsalis pars centralis of the ipsilateral telencephalon, nucleus centralis posterior and the nucleus ventromedialis thalami. In addition, another 5 telencephalic afferent nuclei are found in the diencephalon; the nucleus subrotundus of Sheldon, nucleus preglomerulosus pars anterior, nucleus ventromedialis thalami, nucleus centralis posterior and nucleus posterior thalami.

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.

Concentrations of thyrotropin-releasing hormone in the brain of ataxic mice

Concentrations of thyrotropin-releasing hormone (TRH) were studied in the brain of the Weaver ataxic mouse, the Purkinje cell degenerative ataxic mouse (pcd-ataxic mouse) and the cytosine arabinoside (ara-C)-induced ataxic mouse. The brain tissue was dissected into 4 parts, e.g., hypothalamus, cerebrum, cerebellum and brain stem. TRH concentrations in each part of the brain were measured by radioimmunoassay. TRH concentrations in the brain of Weaver ataxic mice were significantly higher in the cerebellum and brain stem than in the controls. In pcd-ataxic mice, the TRH concentrations in the brain were significantly higher in the cerebrum and brain stem. In ara-C-induced ataxic mice, the concentrations were significantly higher in the cerebrum, cerebellum and brain stem. TRH levels in the hypothalamus of ataxic mice did not differ from those of controls. The elution profile of methanol-extracted cerebellum of ataxic mice on Sephadex G-10 was identical to that of synthetic TRH. These findings suggest that changes in the TRH concentrations in the brain play a pathophysiological role in ataxic mice.

Brain neurotransmitters in dystonia musculorum deformans

We examined histologically and biochemically the brains of two patients with generalized childhood-onset dystonia musculorum deformans. We found no important histologic changes in the basal ganglia, cerebral cortex, higher brain-stem nuclei, locus ceruleus, or raphe nuclei. Similarly, the activity of choline acetyltransferase and the levels of gamma-aminobutyric acid and glutamic acid in the cerebral cortex and basal ganglia were within the control range. In contrast, the norepinephrine concentrations were markedly and consistently decreased in the lateral and posterior hypothalamus, mamillary body, subthalamic nucleus, and locus ceruleus. The serotonin level was subnormal in the dorsal raphe nucleus, as was the dopamine level in the nucleus accumbens and, in one of the two cases, in the striatum. Elevated concentrations of norepinephrine were found in the septum, thalamus, colliculi, red nucleus, and dorsal raphe nucleus; of serotonin, in the globus pallidus, subthalamic nucleus, and locus ceruleus; and of 5-hydroxyindoleacetic acid, in the globus pallidus, subthalamic nucleus, and nuclei raphe centralis inferior and obscurus. The level of homovanillic acid showed little consistent change in the regions examined. We conclude that some of these monoamine changes, especially the pronounced apparent disturbance of noradrenergic brain mechanisms, may represent a basic neurochemical abnormality in dystonia musculorum deformans and may thus be relevant to the pathoneurophysiology and treatment of this disorder.

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.

Myelin proteins in the CNS of 'shaking pups'

Myelin proteins were quantitated in whole tissue and isolated 'myelin fractions' from spinal cord, brainstem and hemispheres of 'shaking pups', a mutation in Springer-Spaniel dogs characterized by hypomyelination of the CNS. The amount of myelin basic protein (MBP) in the brainstem of affected 4-week-old pups was 2.6% of that in age-matched controls, while the levels of 2'3'-cyclic nucleotide phosphodiesterase (CNP) and myelin-associated glycoprotein (MAG) were 10% and 15% of the control levels, respectively. Similar results were obtained in the spinal cord and hemispheres, and the amounts of these proteins in the mutant pups did not change substantially between 4 and 16 weeks of age. The amount of the 21 kDa MBP compared to the 18 kDa MBP was relatively increased in the shaking pups, suggesting that the small amount of myelin formed was immature. The yields of myelin fractions from the mutant pups were very low; e.g., the yield from the brainstems of 4-week-old mutants was only 2.4% of that from age-matched controls and the yield did not increase by 16 weeks. The isolated myelin fractions contained very little MBP (less than 0.5% of total protein) or proteolipid protein, indicating that they were a very immature form of myelin or consisted largely of non-myelin contaminants. MAG in the 'myelin fractions' from the mutant brainstems were 9-15 fold higher and CNP levels were 2-3 fold higher than those in whole homogenates, suggesting that the isolated fractions were enriched in oligodendroglia-derived membranes. Overall, the biochemical results are consistent with a severe hypomyelination of the CNS in which a small amount of immature myelin is formed.

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.

[Biochemical studies of the cerebral ischemia in the rat--changes in cerebral free amino acids, catecholamines and uric acid]

Changes in cerebral free amino acids, catecholamines and uric acid levels were explored for up to 7 days after cerebral ischemia in the rat. Fifty male Sprague-Dawley rats were subjected to occlusion of the middle cerebral artery on the olfactory tract, under halothane anesthesia. The animals were decapitated at 2, 4, 6, 12, 24 hours and 2, 3, 5, 7 days after the surgery, respectively. The brains were rapidly removed. The cerebral hemispheres were divided into right and left halves, and homogenized in sulfosalicylic acid solution. Free amino acids were analyzed by colormetric method. Cathecholamines and uric acid were analyzed by high-performance liquid chromatography. Each parameters were measured both on the ischemic and contralateral hemispheres. The time course of changes in each parameters were observed by means of the ratio, which is the value of ischemic side divided by that of contralateral side. Free amino acids Dicarboxylic group; Decreases in glutamate and increases in glutamine suggest one aspect of detoxication of ammonia within the ischemia tissue. Monocarboxylic group; GABA, glycine, alanine were increased in early ischemic state, and gradually lowered to the normal values. These suggest the impairment of tricarboxylic acid (TCA) cycle in the ischemic tissues, since these amino acids are closely related to TCA cycle. Essential amino acids, except for tryptophan, were increased until the end of study. These increases suggest the utilization of essential amino acids for protein synthesis might be disturbed in the ischemic tissues. Catecholamines and precursors; Norepinephrine and dopamine were lowered gradually. On the other hand, phenylalanine and tyrosine were increased during ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization and identification of alpha-melanocyte-stimulating hormone (alpha-MSH) in the frog brain

The distribution of alpha-melanocyte-stimulating hormone (alpha-MSH) in the central nervous system of the frog Rana ridibunda was determined by immunofluorescence using a highly specific antiserum. alpha-MSH-like containing perikarya were localized in the infundibular region, mainly in the ventral hypothalamic nucleus. A rich plexus of immunoreactive fibers directed towards the ventral telencephalic region was detected. Reverse-phase high-performance liquid chromatography and radioimmunoassay were used to characterize alpha-MSH-like peptides in the frog brain. Chromatographic separation revealed that immunoreactive alpha-MSH coeluted with synthetic des-N alpha-acetyl alpha-MSH, authentic alpha-MSH and their sulfoxide derivatives. The heterogeneity of alpha-MSH-like material in the frog brain was in marked contrast with the figure observed in the intermediate lobe of the pituitary gland where only des-N alpha-acetyl alpha-MSH is present. These findings support the existence of discrete alpha-MSH immunoreactive neurons in the frog brain containing both desacetyl and authentic alpha-MSH.

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.

Myelin in the developing human cerebrum

In order to ascertain the true composition of human myelin at the earliest stages of development and to shed some light on the controversial results published to date, the lipid and protein composition of myelin from unfrozen cerebrum of very young infants was compared to the values obtained later in development and to those obtained by other investigators using frozen human brain. The effect of 3 different procedures of myelin isolation, as well as varying periods of storing the brain in frozen state, were tested on the final composition of myelin. All myelin preparations were of a very high degree of purity, and the lipid composition changed very little either with age or by varying the method or the time of storage of the brain. Protein composition, on the other hand, changed drastically after freezing the brain for increasing periods, and the percentage of myelin basic protein (MBP) decreased to one-third of its original value after about a year of brain storage. However, when myelin was isolated from unfrozen brain immediately after autopsy, very high values of MBP were obtained, even in newborn cerebral myelin, which was quite mature from a morphological as well as from a biochemical point of view. These data reveal that the developmental changes of human myelin are much more subtle than has previously been thought.

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.

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.

Immunohistochemical localization of a melanin concentrating hormone-like peptide in the rat brain

Using antisera generated in rabbits against salmon melanin concentrating hormone (MCH) coupled to human thyroglobulin, the distribution of MCH-like immunoreactivity was mapped throughout the rat central nervous system. The distribution of MCH-like immunoreactivity in rat brain is unique and different from the distribution of other neuropeptides. MCH-like immunoreactive perikarya and fibers are predominant in the posterior hypothalamic area, mostly in the medial forebrain bundle-lateral hypothalamic area subzona incerta and the perifornical area. Cell bodies are located mainly in the medial forebrain bundle and in proximity to well defined hypothalamic nuclei. Fibers are seen throughout the rat brain in all neocortical areas, the neostriatum and the amygdala, in the diencephalon in most hypothalamic nuclei, the habenula, the mamillary body and very dense in the medial forebrain bundle and just ventral to the zona incerta ("subzona incerta"). In the mesencephalon there are fibers in the central gray; in the pons-medulla fibers are contained in the dorsal and ventral parabrachial nuclei; in the tegmental area ventral to the fourth ventricle; in the spinal trigeminal area, the substantia gelatinosa and the reticular nuclei. In the spinal cord there are more fibers in the dorsal than in the ventral horn. The posterior pituitary also contained few MCH-like fibers. It is suggested that a peptide similar, but not identical, to salmon MCH is present in the rat central nervous system.

Regional distribution of the dopamine D2 receptors in the mesotelencephalic dopamine neuron system of human brain

Using the [3H]spiroperidol binding technique, we performed a regional distribution of the D2 receptors in the human mesotelencephalic dopamine neuron system. D2 receptors were found in decreasing order of concentration in caudate nucleus greater than putamen greater than nucleus accumbens greater than globus pallidus greater than amygdala greater than substantia nigra. D2 receptors could not be detected in any cortical region. The nigrostriatal and mesolimbic components of the mesotelencephalic dopamine neuron system are easily to reconstitute. If there exists a mesocortical component in man, its actions appear not to be mediated by D2 receptors.

Proteolipids in developing rat brain

In this report data are summarized on changes in the quantity of proteolipid protein (PLP), its amino acid composition, and the lipid moiety of these lipid-protein complexes in rat brain during postnatal development. In all three parts of the central nervous system (CNS) studied (cerebral hemispheres, medulla oblongata and spinal cord) the main pattern of PLP accumulation is on the whole similar. PLP content is very low in the newborn, and it increased 12 to 20-fold during development. The highest rate of PLP accumulation is observed in the period from 10 to 30 days after birth. Against the background of general similarity the concentration of some amino acids such as lysine, proline, tyrosine in PLP somewhat increased during development, while that of aspartic acid, glutamic acid, glycine, and leucine decreased. Soluble proteolipid complexes, purified to various degree from lipids were isolated from brain of rats of different ages. As compared with the original lipid extracts from which they were obtained, the crude and especially purified proteolipids in all the animals studied were enriched in acidic phospholipids (PhL). This prevalence of acidic PhL increased with age. During the development in phospholipid moiety of proteolipids (PL) the content of phosphatidyl serine, sphingomyelin and mainly diphosphatidyl glycerol increases and that of phosphatidyl inositol and especially phosphatidyl choline decreases. The concentration of acidic PhL more tightly bound with PLP appreciably increases with age. Most of these changes occur mainly during the second decade after birth.

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)

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.

Immunocytochemical mapping of 1B236, a brain-specific neuronal polypeptide deduced from the sequence of a cloned mRNA

The 318-amino acid, carboxy-terminal sequence of the putative brain-specific polypeptide 1B236 was deduced from the nucleotide sequence of its cloned brain-specific mRNA. Antisera raised against selected synthetic peptide fragments of this protein were used to map the cellular location of the presumptive gene product in the brains of normal or colchicine-pretreated adult rats. Antisera directed against any of three C-terminally located, but nonoverlapping, nonhomologous, synthetic peptide segments (P5, P6, or P7) produced virtually identical maps of intensely immunoreactive neuropil staining. The immunoreactivity was distributed heterogeneously and was most pronounced within olfactory, somatosensory, and limbic systems, and was more modest in certain motor and auditory structures. In colchicine-pretreated rats, large, multipolar perikarya were observed within the amygdala, caudate-putamen, cingulate, parietal, and piriform cortices, as well as in particular diencephalic and pontine nuclei. Smaller immunoreactive neurons with more limited dendritic extensions were observed in the olfactory bulb, the cerebellar cortex, and the dorsal horn and intermediolateral cell columns of the spinal cord. No immunoreactivity was observed in visceral structures innervated by the autonomic nervous system or in non-neural tissues. In addition to the virtually superimposable maps produced by antisera to all three synthetic fragments selected from the C-terminus of 1B236, some uniquely reactive sites were seen. Antisera to the most N-terminal of the three synthetic immunogens (P5) were reactive with neurons of the medial trapezoid nucleus and in nerve terminals surrounding the deep cerebellar nuclei. Antisera against the most C-terminal synthetic immunogen (P7) were reactive with neurons of the paraventricular and supraoptic hypothalamic nuclei. These data demonstrate that the 1B236 protein is located within selected neuronal elements within functionally related cellular circuits established more formally by other methods. Our data show that protein 1B236-immunoreactive cells share at least the expression of this protein and suggest that these cells may also be related epigenetically or evolutionarily. These data, together with other subcellular, ultrastructural, and electrophysiological properties of 1B236, suggest that this protein could be considered as a prohormone capable of yielding several final candidate transmitter products.

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.

The prefrontal 'cortex' in the pigeon. Biochemical evidence

Concentrations of dopamine and noradrenaline were determined in 6 regions of the telencephalon and in the cerebellum of the pigeon. Noradrenaline was rather evenly distributed. A significant variation was found of the dopamine-noradrenaline ratio (DA:NA), a measure which makes it possible to distinguish dopamine found in dopaminergic fibers from dopamine which is precursor of noradrenaline. The highest ratio was found in the anteroventromedial region (containing the presumed homologue of the mammalian neostriatum), and the next highest in the posteroventrolateral region (containing the archistriatum). Like in mammals, the lowest concentration of the non-precursor dopamine in the pigeon brain seems to be contained in the cerebellum. Among the regions which show physiological and anatomical similarities with the mammalian cerebral cortex, the DA:NA ratio was significantly higher in the posterodorsolateral, than in the posterodorsomedial and anterodorsomedial regions. The two dorsomedial regions contain the equivalents of the hippocampus and sensory cortical areas of mammals. The strong dopamine innervation of the posterodorsolateral region is comparable to that of the mammalian prefrontal cortex.