Immunohistochemical localization of delta sleep-inducing peptide (DSIP) in the brain and pituitary of the cartilaginous fish Scyliorhinus canicula.

The distribution of delta sleep-inducing peptide (DSIP) in the brain and pituitary of the cartilaginous fish Scyliorhinus canicula was investigated using the indirect immunofluorescence technique. Delta sleep-inducing peptide-like immunoreactive cell bodies were mainly observed in the nucleus lateralis tuberis of the hypothalamus. Immunolabeled perikarya were also distributed in the nucleus lobi lateralis hypothalami and in the dorso-lateral wall of the recessus posterioris. Most of these cells, located in the subependymal layers of the infundibulum and lateral lobes, had the typical aspect of cerebrospinal fluid-contacting elements. The DSIP-like immunoreactive fibers were localized in the basal telencephalon, within the regions of the nucleus interstitialis commissurae anterioris and the nucleus entopeduncularis. A dense network of DSIP-positive fibers was seen throughout the midcaudal hypothalamus, the lateral lobes, and the posterior lobe. In the pituitary, numerous DSIP-like immunoreactive cells were detected in the median lobe of the pars distalis. In particular, a high concentration of cells was seen in the dorsal wall of the median lobe, an area which is known to contain melanin-concentrating hormone (MCH)-producing cells. Comparison of the distribution of DSIP- and MCH-like immunoreactive cells revealed that the two neuropeptides are stored in the same cells of the median lobe of the pituitary. These findings provide the first evidence for the presence of a DSIP-related peptide in fish. The distribution of the immunoreactive material supports the view that DSIP may act as a neuromodulator and/or a hypophysiotropic factor. Moreover, the presence of DSIP-like immunoreactive cells in the pars distalis suggests that this peptide may exert autocrine or paracrine effect in the pituitary.     

Melanin-concentrating hormone (MCH) immunoreactivity in the brain and pituitary of the dogfish Scyliorhinus canicula. Colocalization with alpha-melanocyte-stimulating hormone (alpha-MSH) in hypothalamic neurons

The distribution of melanin-concentrating hormone (MCH) in the central nervous system of the dogfish Scyliorhinus canicula was determined by indirect immunofluorescence and peroxidase-anti-peroxidase techniques, using an antiserum raised against synthetic salmon MCH. Three groups of MCH-positive cell bodies were localized in the posterior hypothalamus. The most prominent cell group was detected in the nucleus sacci vasculosi. Scattered MCH-immunoreactive cells were observed in the nucleus tuberculi posterioris and in the nucleus lateralis tuberis. At the pituitary level, the caudal part of the median lobe of the pars distalis contained strongly MCH-positive perikarya. Some of these cells were liquor-contacting-type. Immunoreactive fibers originating from the hypothalamic perikarya projected throughout the dorsal wall of the posterior hypothalamus. Positive fibers were also detected within the thalamus and the central gray of the mesencephalon. The distribution of MCH-containing neurons was compared to that of alpha-MSH-immunoreactive elements using consecutive, 5-micron thick sections. Both MCH- and alpha-MSH-immunoreactive peptides were found in the same neurons of the nucleus sacci vasculosi. These data suggest that MCH and alpha-MSH, two neuropeptides which exert antagonistic activities on skin melanophores, may also act in a coordinate manner in the central nervous system of cartilaginous fish.     

Occurrence of bombesin-like immunoreactivity in the brain of the cartilaginous fish,Scyliorhinus canicula

Summary The presence and distribution of bombesin-like material were investigated in the brain of the cartilaginous fishScyliorhinus canicula using conventional immunocytochemical techniques. Perikarya containing bombesin-like immunoreactivity were identified in the hypothalamus, within the magnocellular component of the preoptic nucleus. Some immunopositive elements appeared to be of cerebrospinal fluid-contacting type. Beaded immunoreactive fibers were seen crossing the ventral telencephalon and the whole hypothalamus. An important tract of fibers was found in the infundibular floor and in the median eminence, in close contact with the vascular system of the pituitary portal plexus. A moderate number of positive fibers innervated the habenular complex and the dorsal wall of the posterior tuberculum. These findings indicate that a neuropeptide strictly related to amphibian bombesin is located in specific hypothalamic neurons ofS. canicula. The distribution of the immunoreactive fibers and terminals suggests that, in fish, this peptide, may be involved in neuroendocrine and neuromodulator functions.     

Distribution of FMRFamide-like immunoreactivity in the brain of the elasmobranch fish Scyliorhinus canicula.

The distribution of FMRFamide-like-immunoreactive peptides was investigated in the brain and pituitary of the elasmobranch fish Scyliorhinus canicula using the indirect immunofluorescence technique. FMRFamide-immunoreactive cells and fibers were mainly observed in the telencephalon and the diencephalon, while other brain structures were almost unstained. In the telencephalon, FMRFamide-like-containing neurons were seen in the caudal part of the area periventricularis pallialis, in the posterior area of the nucleus septi medialis and in the nucleus septi caudoventralis. In the diencephalon, numerous FMRFamide-positive cell bodies were observed in the hypothalamus, ventral thalamus and posterior tuberculum. The highest density of immunofluorescent perikarya was found in the nucleus lobi lateralis hypothalami and in the nucleus periventricularis hypothalami. More caudally, the mesencephalon and the caudal brainstem only contained scattered varicose FMRFamide-immunoreactive fibers. Stained fibers were also identified in the median eminence and several FMRFamide-like-positive cells were detected in the dorsal and rostral parts of the neurointermediate lobe of the pituitary. These data indicate that substances related to the molluscan cardioexcitatory peptide FMRFamide are widely distributed in the brain of S. canicula, suggesting their implication in neuroendocrine and/or neuromodulatory functions.     

Localization of serotonin in the hypothalamus and the mesencephalon of the guinea-pig

Summary The distribution of serotonin in the hypothalamus and the mesencephalon of guinea-pigs pretreated with both pargyline and L-tryptophan was investigated immunohistochemically using monoclonal antibodies to 5-HT. 5-HT-positive fibers and varicosities appeared distributed throughout the hypothalamus. Some areas showed a greater density of immunoreactivity: the suprachiasmatic nucleus, the region of the supraoptic crest, the area of the medial forebrain bundle, the ventral part of the nucleus ventromedialis, the median eminence and the ventral part of the mammillary bodies. 5-HT nerve fibers were also scattered in the posterior lobe of the pituitary. An extensive supraependymal plexus of immunoreactive axons was observed in most ventricular regions. No 5-HT positive cell bodies were present in the hypothalamus of the guinea-pig under our experimental conditions, whereas an intense serotonin immunoreactivity was detected in perikarya of the brain stem. 5-HT cell bodies were found predominantly in the raphe region including the nucleus raphe dorsalis and raphe medianus, nucleus interpeduncularis, reticular formation and dorsal area of the medial lemniscus.     

Presence and distribution of LHRH- and alpha-MSH-like immunoreactive nerve fibers in the epithalamus of the sheep

The presence of luteinizing-hormone-releasing hormone (LHRH)-like and alpha-melanocyte-stimulating hormone (alpha-MSH)-like immunoreactive fibers, nerve terminals or cellular elements in the pineal gland of the sheep has been investigated by immunohistochemistry. No LHRH-or alpha-MSH-like immunoreactive fiber, nerve terminals or cellular elements have been demonstrated in the pineal organ of the sheep. However, LHRH- and alpha-MSH-like immunoreactive fibers are present in the posterior commissure. Immunoreactive LHRH and alpha-MSH nerve endings are evident in the medial and lateral habenular nuclei. Discrepancies with the results obtained in other mammals are indicative of species differences in the distribution of LHRH- and alpha-MSH-like immunoreactive material in the pineal region.     

A reinvestigation of the Gn-RH (gonadotrophin-releasing hormone) systems in the goldfish brain using antibodies to salmon Gn-RH

Summary The organization of Gn-RH systems in the brain of teleosts has been investigated previously by immunohistochemistry using antibodies against the mammalian decapeptide which differs from the teleostean factor. Here, we report the distribution of immunoreactive Gn-RH in the brain of goldfish using antibodies against synthetic teleost peptide.Immunoreactive structures are found along a column extending from the rostral olfactory bulbs to the pituitary stalk. Cell bodies are observed within the olfactory nerves and bulbs, along the ventromedial telencephalon, the ventrolateral preoptic area and the latero-basal hypothalamus. Large perikarya are detected in the dorsal midbrain tegmentum, immediately caudal to the posterior commissure. A prominent pathway was traced from the cells located in the olfactory nerves through the medial olfactory tract and along all the perikarya described above to the pituitary stalk. In the pituitary, projections are restricted to the proximal pars distalis. A second immunoreactive pathway ascends more dorsally in the telencephalon and arches to the periventricular regions of the diencephalon. Part of this pathway forms a periventricular network in the dorsal and posterior hypothalamus, whereas other projections continue caudally to the medulla oblongata and the spinal cord. Lesions of the ventral preoptic area demonstrate that most of the fibers detected in the pituitary originate from the preoptic region.     

Alpha-melanotropin in the frog brain: regional distribution, quantification and subcellular distribution

The distribution of alpha-MSH containing neurons was studied by immunofluorescence in the brain of the frog Rana ridibunda. Most immunoreactive cell bodies were found in the ventral hypothalamic area. A rich network of fluorescent fibers was observed in the ventral infundibular region, coursing towards the preoptic area and the ventral telencephalon. Some fibers, directed backwards, project into median eminence. By means of a specific radioimmunoassay, the concentrations of alpha-MSH immunoreactive material has been determined in 10 different regions of the brain. The highest concentrations were observed in the infundibular and the preoptic regions. Using the immunogold technique, electron microscopy showed that immunostaining was restricted to 70-100 nm dense core vesicles in positive cell bodies and fibers. These results suggest that, in addition to well known hormonal (melanotropic) activity, alpha-MSH could play the role of a neurotransmitter in the frog brain.     

Localization and identification of Neuropeptide Y (NPY)-like immunoreactivity in the frog brain

The distribution of neuropeptide Y (NPY) in the central nervous system of the frog Rana ridibunda was determined by immunofluorescence using a highly specific antiserum. NPY-like containing perikarya were localized in the infundibulum, mainly in the ventral and dorsal nuclei of the infundibulum, in the preoptic nucleus, in the posterocentral nucleus of the thalamus, in the anteroventral nucleus of the mesencephalic tegmentum, in the part posterior to the torus semicircularis, and in the mesencephalic cerebellar nucleus. Numerous perikarya were also distributed in all cerebral cortex. Important tracts of immunoreactive fibers were found in the infundibulum, in the preoptic area, in the lateral amygdala, in the habenular region, and in the tectum. The cerebral cortex was also densely innervated by NPY-like immunoreactive fibers. A rich network of fibers was observed in the median eminence coursing towards the pituitary stalk. Scattered fibers were found in all other parts of the brain except in the cerebellum, the nucleus isthmi and the torus semicircularis, where no immunoreactivity could be detected. NPY-immunoreactive fibers were observed at all levels of the spinal cord, with particularly distinct plexus around the ependymal canal and in the distal region of the dorsal horn. At the electron microscope level, NPY containing perikarya and fibers were visualized in the ventral nuclei of the infundibulum, using the peroxidase-antiperoxidase and the immunogold techniques. NPY-like material was stored in dense core vesicles of 100 nm in diameter. A sensitive and specific radioimmunoassay was developed. The detection limit of the assay was 20 fmole/tube. The standard curves of synthetic NPY and the dilution curves for acetic acid extracts of cerebral cortex, infundibulum, preoptic region, and mesencephalon plus thalamus were strictly parallel. The NPY concentrations measured in these regions were (pmole/mg proteins) 163±8, 233±16, 151±12 and 60±13, respectively. NPY was not detectable in cerebellar extracts. After Sephadex G-50 gel filtration of acetic acid extracts from whole frog brain, NPY-like immunoreactivity eluted in a single peak. Reverse phase high performance liquid chromatography (HPLC) and radioimmunoassay were used to characterize NPY-like peptides in the frog brain. HPLC analysis revealed that infundibulum, preoptic area and telencephalon extracts contained a major peptide bearing NPY-like immunoreactivity. The retention times of frog NPY and synthetic porcine NPY were markedly different. HPLC analysis revealed also the existence, in brain extracts, of several other minor components cross-reacting with NPY antibodies. These results provide the first evidence for the presence of NPY in the brain of a non-mammalian chordate and indicate that the structure of NPY is preserved among the vertebrate phylum. The abundance of NPY producing neurons in the hypothalamus and telencephalon suggests that this peptide may play both neuroendocrine and neurotransmitter functions in amphibians.     

Calcitonin gene-related peptide: detailed immunohistochemical distribution in the central nervous system

With the use of an antiserum generated in rabbits against synthetic human calcitonin gene-related peptide (CGRP) the distribution of CGRP-like immunoreactive cell bodies and nerve fibers was studied in the rat central nervous system. A detailed stereotaxic atlas of CGRP-like neurons was prepared. CGRP-like immunoreactivity was widely distributed in the rat central nervous system. CGRP positive cell bodies were observed in the preoptic area and hypothalamus (medial preoptic, periventricular, anterior hypothalamic nuclei, perifornical area, medial forebrain bundle), premamillary nucleus, amygdala medialis, hippocampus and dentate gyrus, central gray and the ventromedial nucleus of the thalamus. In the midbrain a large cluster of cells was contained in the peripeduncular area ventral to the medial geniculate body. In the hindbrain cholinergic motor nuclei (III, IV, V, VI, VII XII) contained CGRP-immunoreactivity. Cell bodies were also observed in the ventral tegmental nucleus, the parabrachial nuclei, superior olive and nucleus ambiguus. The ventral horn cells of the spinal cord, the trigeminal and dorsal root ganglia also contained CGRP-immunoreactivity. Dense accumulations of fibers were observed in the amydala centralis, caudal portion of the caudate putamen, sensory trigeminal area, substantia gelatinosa, dorsal horn of the spinal cord (laminae I and II). Other areas containing CGRP-immunoreactive fibers are the septal area, nucleus of the stria terminalis, preoptic and hypothalamic nuclei (e.g., medial preoptic, periventricular, dorsomedial, median eminence), medial forebrain bundle, central gray, medial geniculate body, peripeduncular area, interpeduncular nucleus, cochlear nucleus, parabrachial nuclei, superior olive, nucleus tractus solitarii, and in the confines of clusters of cell bodies. Some fibers were also noted in the anterior and posterior pituitary and the sensory ganglia. As with other newly described brain neuropeptides it can only be conjectured that CGRP has a neuroregulatory action on a variety of functions throughout the brain and spinal cord.     

Proopiomelanocortin (POMC)-related peptides in the brain of the rainbow trout, Salmo gairdneri

We have investigated the presence of ACTH, -MSH and β-endorphin, three peptides which derive from the multifunctional precursor protein proopiomelanocortin (POMC) in the brain of the rainbow trout Salmo gairdneri. Using both the indirect immunofluorescence and peroxidase-antiperoxidase techniques, a discrete group of positive cells was identified in the hypothalamus, within the anterior part of the nucleus lateralis tuberis. -MSH-containing neurons represented the most abundant immunoreactive subpopulation. Coexistence of -MSH, ACTH and β-endorphin was observed in the lateral part of the nucleus. ACTH- and β-endorphin-containing cells were mainly distributed in the rostral and caudal regions of the nucleus. In the medial portion of the nucleus lateralis tuberis, numerous cells were only stained for -MSH. Moderate to dense plexuses of immunoreactive fibers were observed in the ventral thalamus and the floor of the hypothalamus. Some of these fibers projected towards the pituitary. The concentrations of ACTH, -MSH and β-endorphin-like immunoreactivities were measured in microdissected brain regions by means of specific radioimmunoassays. Diencephalon, mesencephalon and medulla oblongata extracts gave dilution curves which were parallel to standard curves. The highest concentrations of POMC-derived peptides were found in the diencephalon (-MSH: 4.28±0.43 ng/mg prot.; ACTH: 1.08±0.09 ng/mg prot.; β-endorphin: 1.02±0.1 ng/mg prot.), while lower concentrations were detected in the mesencephalon, medulla oblongata and telencephalon. The present results demonstrate that various peptides derived from POMC coexist within the same cell bodies of the fish hypothalamus. Taken together, these data suggest that expression and processing of POMC in the fish brain is similar to that occurring in pituitary melanotrophs.     

Localization of atrial natriuretic factor (ANF)-related peptides in the central nervous system of the elasmobranch fish Scyliorhinus canicula

We have investigated the localization of atrial natriuretic factor (ANF)-like immunoreactivity in the central nervous system of the cartilaginous fish, Scyliorhinus canicula, using the indirect immunofluorescence technique. Immunoreactive perikarya and fibers were observed in two regions of the telencephalon, the area superficialis basalis and the area periventricularis ventrolateralis. In the diencephalon, the hypothalamus exhibited a moderate number of ANF-containing neurons and fibers located in the preoptic and periventricular nuclei and in the nucleus lateralis tuberis. The most important group of ANF-immunoreactive cells was observed in the nucleus tuberculi posterioris of the diencephalon. In contrast, the mesencephalon showed only a few ANF-positive nerve processes located in the tegmentum mesencephali. Numerous fine fibers and nerve terminals were found in the dorsal area of the neurointermediate lobe of the pituitary. These results provide the first evidence for the presence of ANF-related peptides in the brain of a cartilaginous fish. The widespread distribution of ANF-positive cells and fibers in the brain and pituitary suggests that this peptide may act both as a neurotransmitter and (or) a neurohormone in fish.     

Organization of histamine-containing neurons in the brain of the crested newt,Triturus carnifex

The distribution of immunoreactivity for histamine was studied in the brain of the urodele Triturus carnifex using the indirect immunofluorescence method. Histamine-immunoreactive cell bodies were localized in the caudal hypothalamus within the dorsolateral walls of the infundibular recesses. These immunoreactive cell bodies were pear-shaped, bipolar and frequently of the cerebrospinal-fluid-contacting type. Histaminergic nerve fibers were detected in almost all parts of the brain. Dense innervation was seen in the telencephalic medial pallium and ventral striatum, the neuropil of the preoptic area, the septum, the paraventricular organ, the posterior commissure, the caudal hypothalamus, the ventral and lateral mesencephalic tegmentum. Medium density innervation was observed in the lateral mesencephalic tegmentum and optic tectum. Poor innervation was present in the telencephalic dorsal pallium and in the central gray of the medulla oblongata. Few fibers occurred in the olfactory bulbs and in the telencephalic lateral pallium. Double immunofluorescence staining, using an antibody against tyrosine hydroxylase, showed that histamine-immunostained somata and those containing tyrosine-hydroxylase-like immunoreactivity were co-distributed in the tuberal hypothalamus. No co-occurrence of histamine-like and tyrosine hydroxylase-like immunostaining was seen in the same neuron. The pattern of histamine-immunoreactive neurons in the newt was similar to that described in other vertebrates. Our observations, carried out on the apparently simplified brain of the newt confirm that the basic histaminergic system is well conserved throughout vertebrates.     

Organization of neuropeptide tyrosine-like immunoreactive system in the brain of the Antarctic fish, Trematomus bernacchii

Antarctic notothenioids have developed unique freezing-resistance adaptations, including brain diversification, to survive in the subzero waters of the Southern Ocean surrounding Antarctica. In this study we have investigated the anatomical distribution of neuropeptide tyrosine (NPY)-like immunoreactive elements in the brain of the Antarctic fish Trematomus bernacchii, by using an antiserum raised against porcine NPY. Perikarya exhibiting NPY-like immunoreactivity were observed in distinct regions of the brain. The most rostral group of immunoreactive perikarya was found in the telencephalon, within the entopeduncular nucleus. In the diencephalon, three groups of NPY-like immunoreactive perikarya were found in the hypothalamus. Two groups of positive cell bodies were found in distinct populations of the preoptic nucleus, whereas the other group was found in the nucleus of the lateral recess. More caudally, NPY immunoreactivity was detected in large neurons located in the subependymal layers of the dorsal tegmentum of the mesencephalon, medially to the torus semicircularis. NPY-like immunoreactive nerve fibres were more widely distributed throughout the telencephalon to the rhombencephalon. High densities of nerve fibres and terminals were observed in several regions of the telencephalon, olfactory bulbs, hypothalamus, tectum of the mesencephalon and in the ventral tegmentum of the rhombencephalon. The distribution of NPY-like immunoreactive structures suggests that, in Trematomus, this peptide may be involved in the control of several brain functions, including olfactory activity, feeding behaviour, and somatosensory and visual information. In comparison with other neuropeptides previously described in the brain of Antarctic fish, NPY is more widely distributed. Our data also indicate the existence of differences in the brain distribution of NPY between Trematomus and other teleosts. In contrast with previous results reported in other fish, Trematomus contains positive fibres in the olfactory bulbs and immunoreactive perikarya in the nucleus of the lateral recess, whereas NPY-immunopositive cell bodies are absent in the thalamus and rhombencephalon, and no NPY immunoreactivity is present in the pituitary. These differences could be related to the Antarctic ecological diversity of notothenioids living at subzero temperatures.     

Localization of atrial natriuretic factor (ANF)-related peptides in the central nervous system of the elasmobranch fish Scyliorhinus canicula

We have investigated the localization of atrial natriuretic factor (ANF)-like immunoreactivity in the central nervous system of the cartilaginous fish, Scyliorhinus canicula, using the indirect immunofluorescence technique. Immunoreactive perikarya and fibers were observed in two regions of the telencephalon, the area superficialis basalis and the area periventricularis ventrolateralis. In the diencephalon, the hypothalamus exhibited a moderate number of ANF-containing neurons and fibers located in the preoptic and periventricular nuclei and in the nucleus lateralis tuberis. The most important group of ANF-immunoreactive cells was observed in the nucleus tuberculi posterioris of the diencephalon. In contrast, the mesencephalon showed only a few ANF-positive nerve processes located in the tegmentum mesencephali. Numerous fine fibers and nerve terminals were found in the dorsal area of the neurointermediate lobe of the pituitary. These results provide the first evidence for the presence of ANF-related peptides in the brain of a cartilaginous fish. The widespread distribution of ANF-positive cells and fibers in the brain and pituitary suggests that this peptide may act both as a neurotransmitter and (or) a neurohormone in fish.     

Distribution of a novel avian gonadotropin-inhibitory hormone in the quail brain

We recently identified a novel hypothalamic neuropeptide inhibiting gonadotropin release in the quail brain and termed it gonadotropin inhibitory hormone (GnIH). In this study, we investigated the localization and distribution of GnIH in both sexes of adult quails by immunohistochemistry with a specific antiserum against GnIH and in situ hybridization. Quantitative analysis demonstrated that the concentration of GnIH in the diencephalon was greater than that in the mesencephalon without sex difference. GnIH concentrations in the cerebrum and cerebellum were below the level of detectability. Clusters of GnIH-like immunoreactive (GnlH-ir) cell bodies were localized in the paraventricular nucleus (PVN) of the hypothalamus. There was no significant difference in the number of GnlH-ir cells in the PVN between males and females. By double immunostaining with antisera reacting with GnIH or avian posterior pituitary hormones (vasotocin and mesotocin), GnIH-ir cells were found to be parvocellular neurons in the ventral portion of PVN, which showed no immunoreaction with the antisera against vasotocin and mesotocin. In situ hybridization revealed the cellular localization of GnIH mRNA in the PVN. GnIH-ir nerve fibers were however widely distributed in the diencephalic and mesencephalic regions. Dense networks of immunoreactive fibers were found in the ventral paleostriatum, septal area, preoptic area, hypothalamus, and optic tectum. The most prominent fibers were seen in the median eminence of the hypothalamus and the dorsal motor nucleus of the vagus in the medulla oblongata. Thus, GnIH may participate not only in neuroendocrine functions, but also in behavioral and autonomic mechanisms.     

Distribution of gastrin and CCK-like peptides in rat brain

Summary The distribution of gastrin and CCK-like peptides in the rat brain was studied by immunocytochemistry using an antiserum reacting equally well with both groups of peptides. Immunoreactive nerve cell bodies were detected in all cortical areas, in the hippocampus where they were particularly numerous, in the mesencephalic central gray and in the medulla oblongata. After colchicine treatment immunoreactive material appeared also in cell bodies of the magnocellular hypothalamic system. Immunoreactive nerve fibers were widely distributed in the brain. Particularly dense accumulations were seen in the hippocampus near the ventral surface of the brain, in the caudate nucleus, in the interpeduncular nucleus, the parabrachial nucleus, the dorsal part of the medulla oblongata and in the dorsal horn of the spinal cord. In the hypothalamus immunoreactive nerve fibers were observed in all nuclei, being most frequent in the ventromedial, dorsal and lateral hypothalamic nuclei. A rich supply of nerve fibers was seen in the outer zone of the median eminence and in the neurohypophysis. From previous immunochemical analysis it appears that the peptide demonstrated in most parts of the brain is identical with CCK-8. In the neurosecretory cell bodies of the hypothalamus, the median eminence and the neurohypophysis, however, the immunoreactive material is probably identical with gastrin.     

Immunocytochemical localization of a galanin-like peptidergic system in the brain of two urodele and two anuran species (Amphibia).

Galanin-like immunoreactivity was localized in the brain of Urodela (Ambystoma, Pleurodeles) and Anura (Bufo, Xenopus) by immunocytochemistry with anti-porcine galanin antiserum. In the four species, immunoreactive perikarya were observed in the telencephalon (striatum, amygdala), diencephalon preoptic area mainly along the anterodorsal wall of the preoptic recessus, suprachiasmatic nucleus, lateral hypothalamus, ventral and dorsal infundibular nuclei, paraventricular organ, and rhombencephalon (nucleus of the solitary tract). Galaninergic fibres extended in similar regions and in the medial septum, ventral telencephalon, ventral hypothalamus, median eminence, and various mesencephalic and rhombencephalic regions. Contacts with the cerebrospinal fluid cavity occurred along the preoptic recessus (Ambystoma) and the ventral infundibular wall (all species). Fibres were scarce in the neurohypophysis. The distal and intermediate lobes of the pituitary were virtually devoid of immunoreactivity. The galaninergic system appeared more developed in adult amphibia than in young animals, suggesting the stimulating influence of sex steroids on the expression of galanin as previously described in Anguilla. The extensive distribution of the galanin-like immunoreactive neurons in amphibian brains suggests that this peptide may act as a neuromodulatur and/or neurotransmitter.     

Galanin-like immunoreactivity in the brain and pituitary of the "four-eyed" fish, Anableps anableps

The distribution of galanin (GAL)-like immunoreactivity was investigated in the brain and pituitary of the "four-eyed" fish, Anableps anableps. GAL-immunoreactive (GAL-ir) perikarya were located in the area ventralis telencephali pars supracommissuralis, nucleus preopticus periventricularis, nucleus preopticus pars parvocellularis, nucleus preopticus pars magnocellularis, nucleus lateralis tuberis ventralis, nucleus lateralis tuberis lateralis, and nucleus lateralis tuberis posterior. A few scattered, GAL-ir neurons were also observed in or adjacent to the nucleus recessus lateralis, nucleus recessus posterioris and lobus facialis (VII). GAL-ir fiber networks were widespread in the brain, with a comparatively higher density in the ventral telencephalic, preoptic and infundibular regions. The neurohypophysis showed GAL-ir innervation and there were GAL-ir cells in the adenohypophysis. The presence of GAL-ir cells in the hypothalamus and in the pituitary is an important asset for the supposed role of GAL-like peptide in neuroendocrine regulation of brain and pituitary functions.