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)

1. Pro-OMLC is amongst a small number of propeptide-encoding genes which are expressed at highest levels in the CNS early in development. 2. The reappearance of the peptide products in injured neurones suggests that they fulfill a function in neuronal growth, differentiation and regeneration. 3. Axonal cues may regulate gene expression in neurones with greater or less functional interaction with their target cells. 4. alpha-MSH and ACTH stimulate the differentiation of neurones by accelerating their energy uptake and axonal growth during its early phases. 5. Their neurotrophic action is mediated through a common N-terminal amino acid sequence. 6. The structure activity requirements of the molecular second messenger responses underlying this action have yet to be conclusively determined. 7. Endorphins may regulate the transition from the mitotic cycle to the onset of differentiation of neurones and glia in the CNS. 8. Little is yet known of the cellular mechanism underlying this response, but the control of peptide processing to favour opiate and non-opiate receptor-mediated responses may be a key factor in determining whether they accelerate or retard neuronal differentiation.
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PMID:The opiomelanocortin peptide family: neuronal expression and modulation of neural cellular development and regeneration in the central nervous system. 256 28

Selected portions of the prevertebral and paravertebral sympathetic and vagal parasympathetic nervous systems have been examined in the genetically diabetic Chinese hamster, an experimental animal model of diabetic gastrointestinal disease. The prevertebral sympathetic superior mesenteric/celiac ganglia, which provide much of the sympathetic innervation of the alimentary tract, developed large numbers of markedly dilated axons, many of which had the ultrastructural features of neuroaxonal dystrophy. Dystrophic axons, many involving presynaptic axonal elements, were increased in frequency in the prevertebral superior mesenteric/celiac ganglia, but not in the paravertebral superior cervical sympathetic ganglia, of chronically diabetic hamsters in comparison with age-matched controls. Dystrophic axons contained substance P- and gastrin-releasing peptide (gastrin-releasing peptide/bombesin)-like staining but were not labeled by antisera directed against vasoactive intestinal peptide, dynorphin-B, somatostatin, leu- and met-enkephalin and neuropeptide tyrosine. Substance P and gastrin-releasing peptide/bombesin containing subpopulations of presynaptic elements in prevertebral sympathetic ganglia are thought to participate in local reflex control of bowel motility and lesions preferentially involving these elements may contribute to bowel dysfunction. Immunohistologic techniques failed to demonstrate dystrophic axons in the superior cervical ganglia. Although morphometric studies failed to show significant axon loss in the abdominal vagus of chronically diabetic Chinese hamsters, evidence of markedly diminished numbers of axons comprising each Schwann cell unit and regenerative collections of Schwann cell processes devoid of axons are consistent with the participation of parasympathetic elements in the pathogenesis of alimentary dysfunction in this model system. These results suggest that selective subpopulations of neuropeptide containing axons are vulnerable to the diabetic condition and that these abnormalities may lead to physiologic dysfunction.
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PMID:Ultrastructural and immunohistochemical characterization of autonomic neuropathy in genetically diabetic Chinese hamsters. 274 19

Using immunocytochemical methods, a beta-endorphin-like immunoreactive substance was identified in the brain of the lizard Lacerta muralis. beta-Endorphin-like neurons were observed in the dorsal posterior part of the paraventricular nucleus and in the caudal region of the nucleus ventromedialis hypothalami. beta-Endorphin-like immunoreactive fibers were also detected in the median eminence. Another cell group displaying beta-endorphin-like immunoreactivity was found in both subdivisions of the oculomotor nucleus and in the periaqueductal gray of the mesencephalon. In addition, a beta-endorphin-like immunoreaction was observed in the perikarya of the Purkinje cells and in their axonal processes. These patterns of immunoreactivity were completely abolished when a specific antiserum was absorbed with its corresponding antigen or with beta-lipotropin. These control tests suggest that the immunoreaction might correspond to a beta-endorphin- or lipotropin-like reaction. The results are discussed in relation to the possibility that a beta-endorphin-like peptide may be involved in hypophysial regulation or neuromodulator activity in the brain of the lizard L. muralis.
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PMID:beta-Endorphin-like immunoreactivity in the brain of the lizard, Lacerta muralis. 295 Dec 94

Adrenocorticotropin binding sites in the rat median eminence have been localized in vivo. These binding sites occur in the basalar zone, which is rich in axonal endings. Using competitive binding and quantitative light-microscope radioautography, we found that the median-eminence binding site, in contradistinction to the adrenal receptor, binds specifically the residue 4-10 region of the adrenocorticotropin molecule. Using quantitative electron-microscope radioautography and median-eminence deafferentation, we localized the binding sites to axon terminals in this region. In time-delayed uptake studies using light-microscope radioautography, we failed to observe concentration of radiolabel in neurons of the medial basal hypothalamus after the direct injection of radioiodinated adrenocorticotropin(1-24) into the median eminence.
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PMID:NH2-terminal specificity and axonal localization of adrenocorticotropin binding sites in rat median eminence. 298 35

Vasopressin (arginine vasopressin, AVP) is present in two types of nerve fibres in the median eminence (ME). First, it is found in nerve terminals that originate in the parvicellular neurones of the hypothalamic paraventricular nucleus (PVN) and abut on the pericapillary space surrounding the fenestrated capillaries of the primary pituitary portal plexus in the external zone (EZ) of the ME. These neurones also synthesize corticotropin-releasing factor (CRF), which acts synergetically with vasopressin to stimulate release of adrenocorticotropin (ACTH) from the pituitary gland (see ref. 7). Second, vasopressinergic axons of the magnocellular neurosecretory system pass through the internal zone (IZ) of the ME to terminate in the neurohaemal contact zone of the neurohypophysis. The involvement of vasopressinergic magnocellular neurones in the control of ACTH secretion is much debated. Of particular interest in this context is the origin of the vasopressin found in pituitary portal blood. Although it has been demonstrated that vasopressin and CRF are present in the same neurosecretory granules of EZ fibres, parallel determinations of vasopressin and CRF in pituitary portal blood have shown alterations of the concentration of vasopressin without a concomitant change in that of CRF. Such a dissociation suggests that either differential release of vasopressin and CRF can occur from a single population of nerve endings, or there are fibres in the pituitary-stalk ME which release vasopressin but not CRF. Here we present evidence for the latter. Our results indicate that stimuli causing depolarization of the axonal membrane in vitro elicit release of vasopressin from nerve fibres in the external and internal zones of the ME.
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PMID:Magnocellular axons in passage through the median eminence release vasopressin. 300 38

Recovery that follows a sciatic nerve crush was studied by counting the number of myelinated axons in cross sections of the sciatic nerve at various times after operation. Treatment with alpha-MSH (10 micrograms/animal, s.c., every 48 h) resulted in an increased number of myelinated axons 10 days after a sciatic nerve crush (3 mm distal to the crush). At postoperation day 22, alpha-MSH increased the number and diameter of axons 20 mm distal to the crush, but 3 mm distal to the crush no effect of alpha-MSH was seen. Treatment with gangliosides (50 mg/kg, i.p., daily) had a somewhat different effect: the number of axons was increased at a later stage and at all distances from the crush. The effect of gangliosides on the axonal diameter was opposite that of alpha-MSH: treatment with gangliosides stimulated the formation of axons with a smaller diameter.
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PMID:Effect of alpha-melanocyte-stimulating hormone on peripheral nerve regeneration in the rat: histological aspects and comparison with the effect of gangliosides. 333 38

The specific immunoreactivity of neurons containing corticotropin-releasing hormone (CRH) or vasopressin (Vp) was studied both centrally, in the parvocellular division of the paraventricular nucleus, and distally, in the external median eminence. Control rats were compared with adrenalectomized rats and with animals supplemented with corticosterone or dexamethasone, either without additional treatment, or 24, and 48 h after an intraventricular injection of colchicine. In all groups of animals, colchicine induced a progressive and parallel decrease in both CRH and Vp immunoreactivity within the axons of the external median eminence. A semi-quantitative estimation of this axonal immunostaining showed that the decrease was clearly correlated with the axons' releasing activity according to the different functional states of the adrenocorticotropic system. Increased rates of hormonal release induced by adrenalectomy could be seen in the accelerated depletion of axonal immunoreactivity whereas corticosteroid supplementation had the opposite effect. Correspondingly, the progressive intensification of the CRH and Vp immunoreactivity within the perikarya following colchicine treatment was further markedly enhanced in adrenalectomized rats and diminished after corticosteroid supplementation. Taken together, these data suggest that in these neurons, perikaryal hormone synthesis may be closely related to the releasing activity of the axon terminals. They further point to appropriate colchicine treatment as useful tool for evaluating the functional state of CRH and Vp neurons of the parvocellular paraventricular nucleus under various experimental conditions.
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PMID:Immunoreactivity of hypothalamo-neurohypophysial neurons which secrete corticotropin-releasing hormone (CRH) and vasopressin (Vp): immunocytochemical evidence for a correlation with their functional state in colchicine-treated rats. 348 34

Several authors have reported reduced levels of pro-opiomelanocortin (POMC)-related peptides in the cerebrospinal fluid (CSF) of patients with Alzheimer's disease (AD), but the mechanisms regulating the CSF content of these substances are still debated. In this case report the processing of POMC peptides has been investigated post-mortem (HPLC and RIA methods) at the pituitary and hypothalamic level in an AD patient and in a control subject. From the results obtained it seems likely that defects of axonal transport and/or secretion rather than synthesis could account for the abnormalities of POMC peptides in the CSF.
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PMID:Abnormal pro-opiomelanocortin processing in Alzheimer's disease. A case report. 369 76

By employing an electron microscopic dual immunolabeling technique, a synaptic association between neurons containing immunoreactive adrenocorticotropin (ACTH) and axonal terminals containing immunoreactive methionine-enkephalin octapeptide (Enk-8) was found in the arcuate nucleus of the rat hypothalamus. The axonal terminals contained many small clear vesicles and some large cored vesicles. At the synaptic portions, membrane specialization was asymmetric.
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PMID:Synaptic association between enkephalin-containing axon terminals and proopiomelanocortin-containing neurons in the arcuate nucleus of rat hypothalamus. 369 89

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


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