Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have investigated the effects of lesioning the hypothalamic paraventricular nucleus (PVN) on the secretion of two corticotropin-releasing neurohormones, vasopressin (VP) and oxytocin (OT), at the median eminence. The experimental model was the median eminence incubated in vitro, the secretion of neurohormones was stimulated by adding 48 mM KCl to the incubation medium. In addition, immunohistochemical staining was performed to correlate the changes in neuropeptide secretion with the distribution of VP and OT immunoreactive elements in the median eminence. Lesioning of the PVN abolished the KCl-induced release of VP 1 week after hypothalamic surgery. After a longer period of postoperative survival (6 weeks), VP release was restored towards normal. The secretion of OT was reduced by 50% at 1 week after lesioning and rose to 400% of control at six weeks. The changes in VP and OT release at the median eminence largely correlated with the immunohistochemical distribution of VP and OT immunopositive nerve fibers in the external zone of the median eminence. Most importantly, 6 weeks after the PVN lesion a dense network of OT immunoreactive varicosities was observed around primary portal capillaries, where normally OT fiber density is very low. These results demonstrate the functional and structural plasticity of VP- and OT-ergic neuronal systems that project to the median eminence. Furthermore, when taken together with earlier studies on the regulation of corticotropin secretion in long-term PVN-lesioned rats, the data indicate an important role for OT in the regulation of pituitary-adrenocortical function in PVN-lesioned rats.
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PMID:Hypophysiotrophic function of vasopressin and oxytocin. 340 54

Opioid peptides including met- and leu-enkephalins are co-stored with catecholamines at similar concentrations in highly purified chromaffin granule fractions from bovine adrenal medulla and large dense cored vesicle (LDV) fractions from bovine splenic nerve. An initial attempt was made to test the universality of the co-storage of enkephalins in LDVs of sympathetic nerves. Based on a number of practical considerations, vasa deferentia were chosen from seven species. Leu-and met-enkephalin contents were quantitated by radio-immunoassays and norepinephrine by HPLC with electrochemical detection. Norepinephrine contents varied 11-fold and generally paralleled the density of sympathetic innervation among the species as reported in the literature. Leu-enkephalin contents varied 26-fold, generally paralleling the percentage composition of LDVs in the respective terminal varicosities among the species and animal size (axonal length). Met-enkephalin contents varied 20-fold, generally paralleling the density of sympathetic innervation, but not the percentage LDVs. Various amounts of met-enkephalin were also likely stored in cells other than sympathetic nerves, including chromaffin-like cells, the incidence of which varied according to species. Thus, the met- to leu-enkephalin ratios varied from 1.2:1 in dog; 1.7-1.9:1 in rabbit, cat and bull; 2.9:1 in man; 8.2:1 in rat; and essentially only met-enkephalin in guinea pig. The data imply differences in the processing of preproenkephalins in the same tissue of different species as well as in different cells of that tissue.
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PMID:Enkephalin contents reflect noradrenergic large dense cored vesicle populations in vasa deferentia. 372 73

Vasoactive intestinal polypeptide (VIP) immunoreactivity is present in varicosities and fibers in the hypothalamic paraventricular nucleus (PVN) in normal control animals. Adrenalectomy and lactation combined with colchicine treatment results in the appearance of a large population of VIP-immunopositive cell bodies in the parvocellular part of the PVN. Adrenalectomy, as well as lactation, significantly increases the number of VIP-positive fibers in the external zone of the median eminence. These observations suggest that the VIP-immunopositive neurons in the PVN may participate in regulating prolactin and corticotropin secretion.
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PMID:Vasoactive intestinal peptide-containing neurons in the paraventricular nucleus may participate in regulating prolactin secretion. 388 55

Immunoreactive fibers and varicosities in the hypothalamic paraventricular nucleus (PVN) were examined by light- and electronmicroscopy, following treatment of brain slices with specific antibodies to adrenocorticotropin (ACTH), beta-endorphin (beta-End) and alpha-melanotropin (alpha-MSH) peptides. In an attempt to provide a more precise, quantitative definition of the densities of immunoreactive elements, sections were analyzed by computer based image-analysis techniques. Fibers and varicosities immunostained with the 3 different antibodies displayed an identical distribution pattern throughout the nucleus suggesting that they are parts of the same, arcuate pro-opiomelanocortin (POMC) neuron system. Although immunoreactive varicosities were found all over the PVN, it was possible to identify a characteristic, density distribution pattern. At the ultrastructural level, immunoreactive presynaptic nerve terminals were observed forming symmetrical synaptic contacts with unlabeled dendrites. The majority of immunoreactive elements were found in the dorsal parvo- and caudal magnocellular subdivisions which give rise to long projections to the lower brainstem. Moderate density of POMC neural elements was observed in the anterior and medial (ventral portion) parvocellular subdivisions which project to the external zone of the median eminence. Only a few, widely scattered immunostained varicosities are found in the medial and lateral magnocellular subdivisions which project to the neurohypophysis. A combined lesion and immunocytochemical approach has shown that the bulk of the afferent neuronal input from arcuate POMC cells enters the PVN from a ventral direction.
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PMID:Analysis of the ACTH/beta-End/alpha-MSH-immunoreactive afferent input to the hypothalamic paraventricular nucleus of rat. 609 42

The content and distribution of Met-enkephalin immunoreactivity in the developing chick gut was studied by radioimmunoassay and immunocytochemistry. Met-enkephalin was detected by radioimmunoassay in the duodenum of the 5-day chick embryo. The concentration in this region increased 4-fold by 13 days of incubation and declined thereafter to the levels found in the 4-week chicken. The concentration of enkephalin in the midgut increased about 2-fold between 9 and 13 days of incubation and remained constant until hatching. In the 7-day duodenum, metenkephalin immunoreactivity was found in a network of darkly stained nodes (accumulations of ganglion cells) faintly stained internodal nerve bundles; this network of immunoreactivity was localized to the myenteric plexus. By 9 days of incubation, the network was more extensive and the intensity of staining was increased. At 13 days of incubation, varicosities were found in the region of the ganglion cells and in internodal nerve bundles. At this time, immunoreactivity was clearly visualized in the submucosal plexus. In the newly hatched chicken, met-enkephalin was found in nerves within the circular smooth muscle, as well as the myenteric and submucosal plexuses. The early appearance of met-enkephalin in the developing chick enteric nervous system suggests this peptide may act as a primary neurotransmitter in the organization and control of gut motility.
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PMID:Development of enkephalinergic neurons in the gut of the chick. 617 Sep 62

Supra-ependymal nerves in mammals (mainly rats) have been shown to contain serotonin (5-hydroxytryptamine, 5-HT) by combined Falck-Hillarp fluorescence histochemistry, ultrastructural monoamine cytochemistry and pharmacology as well as by immunohistochemistry and autoradiography. Supra-ependymal 5-HT cells do not occur. At least in rats, virtually all supra-ependymal nerves contain 5-HT and in our opinion the occasionally described non-5-HT supra-ependymal nerve cells and their processes contribute little to the supra-ependymal nerve plexus (with the possible exception of those cells above the median eminence). The cells of origin of the supra-ependymal 5-HT nerves are situated in raphe nuclei. The axons and terminals (varicosities) contain small and large dense core vesicles in both of which 5-HT is stored. A co-transmitter has not been found among the candidates investigated so far (leu- and met-enkephalin, substance P and gamma-aminobutyric acid (GABA)). The nerves possess uptake mechanisms specific for 5-HT and possibly GABA. Occasionally desmosome-like junctions are observed between 5-HT nerve terminals and ependymal cells but no true synapses. The function of these nerves is not known. They do not appear to regulate ciliary movement, but might influence the shape of ependymal cells.
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PMID:Supra-ependymal serotoninergic nerves in mammalian brain: morphological, pharmacological and functional studies. 618 36

The histological distribution of met-enkephalin-like immunoreactivity was studied in the forebrain (particularly the striatum) and the spinal cord of the rat using the indirect peroxidase-labelled antibody method. In most experiments, vibratome sections of formaldehyde-fixed tissues and purified antibodies were used. The search for optimal conditions for the immunohistochemical reaction lead us to establish that met-enkephalin-containing perikarya of both untreated and colchicinized animals were better demonstrated when tissue were pre-treated with diluted hydrogen peroxide only. The additional treatment of these sections with Triton X-100 (or some other detergents) resulted in the near disappearance of the perikaryal immunoreactivity; on the contrary, numerous met-enkephalin containing nerve fibres and varicosities were then demonstrated in the same region. Using only the hydrogen peroxide treatment, we found numerous met-enkephalin-containing perikarya in the medial and ventral regions of the neostriatum. This distribution was prolonged caudally by the existence of a prominent group of stained somata in the ventral putamen-central nucleus of the amygdala. When intraventricular injections of colchicine were used, positive perikarya were more numerous within the striatum (the globus pallidus excepted) but their distribution was largely the same as in non injected animals. However, some new groups of somata were stained in this case in the forebrain (in the lateral septum, the olfactory tubercle and the hypothalamus particularly). In control animals only few met-enkephalin-containing perikarya were observed in the dorsal horn of the spinal cord when H2O2 pretreatment was used alone and they were numerous only when intraspinal injections of colchicine were performed. Met-enkephalin-containing fibres and varicosities, which were scattered in the whole neostriatum in the conditions used above, became very numerous when the tissue sections were incubated in the presence of Triton X-100. Their density increased markedly from the latero-dorsal to the medio-ventral regions but, in addition, an organization under the form of islands of stronger immunoreactivity was also evidenced. These islands were more numerous ventrally in the anterior neostriatum and in the central region of the "putamen." The dense plexus of immunoreactive nerve fibers forming "tube-like structures" which was always observed in the paleostriatum and in the cranial medial forebrain bundle (islands of Calleja) appeared more diffuse when detergents were used.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Different localizations of Met-enkephalin-like immunoreactivity in rat forebrain and spinal cord using hydrogen peroxide and Triton X-100. Light microscopic study. 636 51

Using two immunocytochemical methods, we have shown in light microscopy that the met-enkephalin-like immunoreactivity within striatum and spinal cord of the rat is differentially distributed in either perikarya or nerve terminals according to the technical conditions used [1]. The present electron microscopic study has been undertaken in order to elucidate the subcellular localization of immunoprecipitates according to the same technical conditions. In the neostriatum, numerous met-enkephalin-containing perikarya were stained (principally at the level of rough endoplasmic reticulum) when tissue sections were treated with hydrogen peroxide (H2O2) only, prior to the immunocytochemical procedure. However, injections of colchicine were required to demonstrate perikarya in the dorsal horn of the spinal cord. At variance with previous results, numerous dendritic profiles and nerve terminals were also reactive in this condition. Neurotubules, mitochondria, large granular vesicles (LGVs) and small synaptic vesicles were stained within these structures. The addition of a low concentration of Triton-X-100 (0.02%) in the first incubation medium often resulted in the disappearance of most perikarya and in the staining of only LGVs in nerve terminals. The addition of a higher concentration of Triton-X-100 (0.1%) produced diffusion of immunoprecipitates at the level of nerve terminals, which was probably responsible for the increased intensity of staining and, subsequently, for the better demonstration of fibre varicosities in light microscopy. On the contrary, the disappearance of reactive perikarya seemed to result from the diffusion of the non-protected peptide out of the cytoplasm. The diverse ultrastructural localizations of met-enkephalin-like immunoreactivity in striatum and spinal cord are finally discussed in light of intrinsic connections or afferents described in the literature.
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PMID:Met-enkephalin-like immunoreactivity in rat forebrain and spinal cord using hydrogen peroxide and Triton X-100. Ultrastructural study. 636 52

When samples of the ventricle surfaces of human post-mortem brain were examined by scanning- and transmission electron microscopy, varicose nerve fibres could be seen traversing among the cilia and microvilli of ependymal cells. The varicosities contained numerous small electron-lucent vesicles and frequent large electron-dense vesicles, and were usually nonsynaptic but occasionally anchored to the surface by desmosome-like junctions. Supra-ependymal nerve fibres were observed in the lateral ventricles (e.g., n. caudatus), foramen of Monro (stria medullaris), third ventricle (habenula) and floor of the fourth ventricle in brains of the five cases examined. However, only in one of these was a yellow formaldehyde-induced fluorescence observed (on the fourth ventricle floor). Its discrete granular appearance, rapid fading and colour were typical of supra-ependymal 5-HT nerve fibres observed in rat brain. Very recent investigations on serial cryostat sections of rat brain ventricle regions revealed the absence of an immunohistochemical reaction with antisera to substance P, leu- and met-enkephalin and glutamic acid decarboxylase, but the presence of a reaction with 5-HT antiserum. The target for impulse-released 5-HT from this nonsynaptic 5-HT nerve plexus, bathed in cerebrospinal fluid, is not yet known.
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PMID:Demonstration of supra-ependymal 5-HT nerve fibres in human brain and their immunohistochemical identification in rat brain. 702 69

Radioimmunoassay (RIA) and high performance liquid chromatography were used in combination with immunocytochemistry to study the development of met-enkephalin (Met-enk) in the rectum and the ganglion of Remak of the chicken. Met-enk was detected by RIA in the rectum at 5 days of incubation (d.i.). The concentration increased from 5-9 d.i. and did not change significantly thereafter. In contrast, the concentration of Met-enk in Remak's ganglion increased throughout the developmental period of study. Met-enk immunoreactivity first appeared in cell bodies in Remak's ganglion at 6 d.i. and in a small number of processes in the wall of the rectum. By 9 d.i., Remak's ganglion contained many immunoreactive cell bodies, some of which extended processes into the wall of the rectum in the region of the myenteric plexus. Varicosities were first seen in the rectum at 13 d.i. and increased in number and staining intensity with developmental age. The fact that immunoreactive cell bodies persist in Remak's ganglion throughout the course of development and send processes into the rectum suggests that a major portion of enkephalinergic innervation of the rectum is extrinsic. On the other hand, the presence of Met-enk immunoreactivity in both nerve cell bodies and processes in rectal explants stripped of Remak's ganglion suggests that this peptide is also contained in intrinsic neurons in the chick rectum.
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PMID:Development of enkephalin in the rectum and ganglion of Remak of the chick. 704 22


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