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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunoreactive galanin-like material was recently shown to co-exist with vasopressin in parvocellular and magnocellular perikarya of the paraventricular nucleus in the anterior hypothalamus of the rat (Melander et al. 1986). Since this distribution pattern differed from our observation of oxytocin-associated galanin-like immunoreactivity (LI) in the neurohypophysis, we compared in series of 0.5-microns thick sections the localisation of galanin-LI with the localisation of oxytocin and vasopressin/dynorphin in the hypothalamus, the median eminence and the neurohypophysis. In the oxytocin system, galanin-LI was intense in oxytocin varicosities of the neurohypophysis. Oxytocin perikarya of the hypothalamic supraoptic and paraventricular nuclei exhibited galanin-LI only after intraventricular injection of colchicine and when sections were treated with trypsin prior to application of the antibody. In the vasopressin/dynorphin system galanin-LI was intense in hypothalamic perikarya after colchicine injection and in neurohypophysial varicosities after treatment of the sections with trypsin. In these neurones, galanin-LI was absent or weak in all elements when treatments with colchicine or trypsin were omitted. Galanin-LI in the neurohypophysis was not co-localised with the numerous fine endings showing GABA-LI. These observations indicate that galanin-like material coexists with vasopressin and oxytocin in the respective magnocellular neurones, although not always in an immunoreactive form.
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PMID:Immunoreactive galanin-like material in magnocellular hypothalamo-neurohypophysial neurones of the rat. 247 16

We have examined the distribution pattern and the density of various neuropeptide, neurotransmitter and enzyme containing neurons in the rat medial septum and the nucleus of the diagonal band of Broca to assess their possible involvement in the septohippocampal, septocortical and septobulbar pathways. Immunohistochemical methods were combined with the retrograde transport of a protein-gold complex injected in the hippocampus, the cingulate cortex or the olfactory bulb. Cholinergic neurons were the most numerous. Galanin-positive neurons were about two or three times less numerous than cholinergic cells. Both these cell types had a similar location though the choline acetyl transferase-like immunoreactive cells extended more caudally in the horizontal limb of the nucleus of the diagonal band of Broca. Immunoreactive cells for other neuroactive substances were few (calcitonin gene-related peptide, luteinizing hormone releasing hormone. [Met]enkephalin-arg-gly-leu) or occasional (dynorphin B, vasoactive intestinal polypeptide, somatostatin, neurotensin, cholecystokinin, neuropeptide Y and substance P). No immunoreactive cells for bombesin, alpha atrial natriuretic factor, corticotropin releasing factor, 5-hydroxytryptamine, melanocyte stimulating hormone, oxytocin, prolactin, tyrosine hydroxylase or arg-vasopressin were present. Choline acetyltransferase- and galanin-like immunoreactive cells densely participate to septal efferents. Cholinergic neurons constituted the bulk of septal efferent neurons. Galanin-positive cells were 22% of septohippocampal, 8% of septocortical, and 9% of septobulbar neurons. Galanin containing septohippocampal neurons were found in the medial septum and the nucleus of the diagonal band of Broca; galanin-positive septobulbar and septocortical cells were limited to the nucleus of the diagonal band of Broca. Occasional double-labellings were noticed with some peptides other than galanin. Luteinizing hormone-releasing hormone, calcitonin gene-related peptide and enkephalin were the most often observed; some other projecting cells stained for vasoactive intestinal polypeptide or dynorphin B. Luteinizing hormone-releasing hormone, calcitonin gene-related peptide and enkephalin were observed in septohippocampal neurons; luteinizing hormone-releasing hormone and vasoactive intestinal peptide were observed in septocortical neurons and calcitonin gene-related peptide, luteinizing hormone-releasing hormone and dynorphin B were observed in septo-bulbar cells. These results show that, in addition to acetylcholine, galanin is a major cellular neuroactive substance in septal projections to the hippocampus, the cingulate cortex and the olfactory bulb. The presence of septal projecting neurons immunoreactive for other peptides shows that a variety of distinct peptides may also participate, but in a smaller number, to septal efferent pathways.
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PMID:Cholinergic and peptidergic projections from the medial septum and the nucleus of the diagonal band of Broca to dorsal hippocampus, cingulate cortex and olfactory bulb: a combined wheatgerm agglutinin-apohorseradish peroxidase-gold immunohistochemical study. 247 18

The purpose of the present study was to quantify the extent to which several peptides and serotonin coexist with substance P or somatostatin in selected lumbar dorsal root ganglia of the cat. The technique for the simultaneous visualization of two antigens by immunofluorescence was used to investigate the coexistence of neuropeptides in the lumbar dorsal root ganglia of colchicine-treated cats. Perikarya immunoreactive for calcitonin gene-related peptide, galanin, leu-enkephalin, somatostatin, and substance P were visualized in both the lumbar 5 and 6 dorsal root ganglia. In contrast, no immunoreactivity was observed for adipokinetic hormone, bombesin, dynorphin A, met-enkephalin, oxytocin, tyrosine hydroxylase, thyrotropin-releasing hormone, vasopressin, vasoactive intestinal peptide, or serotonin in either ganglion examined. Substance P coexisted with calcitonin-gene-related peptide, somatostatin, and leu-enkephalin. Somatostatin was colocalized with calcitonin gene-related peptide, leu-enkephalin, and substance P but coexisted with galanin minimally. The cell area of immunoreactive perikarya was also examined. Data concerning the cross-sectional area of immunoreactive cells indicated that somatostatin-immunoreactive perikarya were generally the largest population observed (up to approximately 6,000 microns2). Somatostatin and calcitonin gene-related peptide, as well as substance P and calcitonin gene-related peptide, coexisted in populations of cell bodies that had a smaller size (less than 2,000 microns2). These results suggest that certain peptides which coexist in the dorsal root ganglia may provide histochemical markers for functional groups of primary afferent neurons.
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PMID:Lumbar dorsal root ganglia of the cat: a quantitative study of peptide immunoreactivity and cell size. 247 1

The present study describes the topography of immunoreactive (ir) oxytocin (OXY) and vasopressin (AVP) neurons in the forebrain of Equus caballus and the coexistence of ir proopiomelanocortin (POMC)-derived peptides in the same cells. These data are compared to those for other mammalian species and the possible significance of species variations is considered. As expected, magnocellular neurons of the equine hypothalamus, which contain ir OXY or AVP, have prominent discernible projections to the neurohypophysis. Further, as in other mammalian species, the field of ir OXY perikarya generally extends rostral and dorsal to groups of ir AVP cell bodies, and caudal projections from OXY neurons appear to be more numerous than ir AVP projections to the brainstem and/or spinal cord. Interestingly, however, the brain of E. caballus also contains: (1) perikarya staining for OXY in the arcuate nucleus, (2) ir AVP and OXY cell bodies in the suprachiasmatic nucleus, and (3) neurons in the supraoptic and paraventricular nuclei that stained for beta-endorphin but not for other posttranslational products of POMC or dynorphin. These results give further credence to the proposal that there is an evolutionary relationship between OXY-, AVP- and POMC-producing hypothalamic neurons. Whether or not species differences in peptide coexistence reflect functional differences in neuronal populations or species differences in residual genomic expression by these neuroendocrine cells warrants further investigation.
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PMID:Topography of oxytocin and vasopressin neurons in the forebrain of Equus caballus: further support of proposed evolutionary relationships for proopiomelanocortin, oxytocin and vasopressin neurons. 252 77

1. Coexisting with oxytocin or vasopressin in the cell bodies and nerve terminals of the hypothalamic-neurohypophysial system are smaller amounts of other peptides. For a number of these "copeptides" there is strong evidence of corelease with the major magnocellular hormones. Guided by the location of their specific receptors we have studied the effects of three copeptides, dynorphin, cholecystokinin (CCK), and corticotropin releasing hormone (CRH), on the secretion of oxytocin and vasopressin from isolated rat neural lobe or neurointermediate lobe preparations in vitro. 2. Dynorphin is coreleased with vasopressin from neural lobe nerve terminals and acts on neural lobe kappa-opiate receptors to inhibit the electrically stimulated secretion of oxytocin. Naloxone augments oxytocin release from the neural lobe in a manner directly proportional to the amount of vasopressin (and presumably dynorphin) released. 3. Cholecystokinin, coreleased with oxytocin by neural lobe terminals, has been shown to have high-affinity receptors located in the NL and to stimulate secretion of both oxytocin and vasopressin. CCK's secretagogue effect was independent of electrical stimulation and extracellular Ca2+ and was blocked by an inhibitor of protein kinase C. 4. CRH, coreleased with OT from the neural lobe, has receptors in the intermediate lobe of the pituitary, but not in the neural lobe itself. CRH stimulates the secretion of oxytocin and vasopressin from combined neurointermediate lobes but not from isolated neural lobes. Intermediate lobe peptides, alpha and gamma melanocyte stimulating hormone, induced secretion of oxytocin and vasopressin from isolated neural lobes. Their effect was, like that of CCK, independent of electrical stimulation and extracellular Ca2+ and blocked by an inhibitor of protein kinase C. 5. Among the CRH-producing parvocellular neurons of the paraventricular nucleus, in the normal rat, approximately half also produce and store vasopressin. After removal of glucocorticoid influence by adrenalectomy, virtually all of the CRH neurons contain vasopressin. 6. The two subtypes of CRH neurosecretory cells found in the normal rat possess different topographical distributions in the paraventricular nucleus, suggesting the possibility of differential innervation. Stress selectively activates the vasopressin containing subpopulation of CRH neurons, indicating that there are separate channels of regulatory input controlling the two components of the parvocellular CRH neurosecretory system.
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PMID:Coexisting peptides in hypothalamic neuroendocrine systems: some functional implications. 257 30

The hypothalamus is one of the most studied areas of the central nervous system. Many of its functions are understood and there is an extensive literature on its role in the control of pituitary hormone secretion, autonomic nervous system activity, regulation of salt, water and food ingestion, body temperature regulation and aspects of behaviour. Although the role of the hypothalamus in the control of pituitary secretion was postulated in the early 1900s, the chemical nature of these control mechanisms has only been documented in the last few years. The opioid peptides represent one particular family of chemical compounds which have been shown to have many effects on pituitary hormone secretion. Exogenous opioids inhibit the neurosecretion of both vasopressin and oxytocin from the posterior pituitary neurosecretory terminals of hypothalamic cell bodies. Opioids also have major actions on the secretory activity of the anterior pituitary which has no innervation from the hypothalamus, but which is regulated by blood-borne factors in the hypophyseal portal circulation which runs from the median eminence of the hypothalamus. It was therefore of considerable interest when it was discovered that endogenous opioid peptides could be detected both in the neurohypophyseal system and in cells which project into the median eminence. The simple presence of a peptide in a neurone does not necessarily imply a function. If, however, we can demonstrate that regulation of the synthesis of the peptide occurs in a manner which corresponds with the expected role of the agent, this provides powerful data in support of a genuine physiological function. The elucidation of the genomic structure of the precursors for the three endogenous opioid peptides has provided us with the ability to measure mRNA for these peptides in defined areas of the brain and to assess their response to appropriate stimuli. Not only does mRNA for the endogenous opioid dynorphin coexist in the same cells as vasopressin but we have now been able to demonstrate that stimuli to vasopressin secretion also result in a markedly increased accumulation of dynorphin mRNA. Similarly, previous studies have shown that opioid peptides derived from another precursor--pro-enkephalin A--coexist with corticotrophin releasing factor in a different group of hypothalamic cells. We have now been able to demonstrate that stresses which result in an accumulation of corticotrophin releasing factor mRNA also result in increased pro-enkephalin mRNA in the same area. This considerably strengthens the hypothesis that endogenous opioids do play a significant role in the control of hypophyseal secretion.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The neuroendocrine paraventricular hypothalamus: receptors, signal transduction, mRNA and neurosecretion. 285 Mar 37

Specific radioimmunoassays were used to measure the effects of hypertonic saline (salt loading), water deprivation, and trichothecene mycotoxin (T2 toxin) on the content of methionine enkephalin (ME), leucine enkephalin (LE), alpha-neoendorphin, dynorphin A, dynorphin B, vasopressin, and oxytocin in the rat posterior pituitary. Concentrations of vasopressin and oxytocin decreased in response to both osmotic stimuli and treatment with T2 toxin, but the decrease was greater with osmotic stimulations. Similarly, concentrations of LE and dynorphin-related peptides declined after salt loading and water deprivation; LE concentrations also decreased after treatment with T2 toxin. The concentration of ME decreased after water deprivation, did not change after salt loading, and increased after T2 toxin treatment. The differentiating effects of these stimuli on the content of immunoreactive LE and ME are consistent with the hypothesis that LE and ME may be localized in separate populations of nerve endings with different roles in the posterior pituitary.
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PMID:Methionine and leucine enkephalin in rat neurohypophysis: different responses to osmotic stimuli and T2 toxin. 285 18

Vasopressin and its carrier protein, vasopressin-associated neurophysin, are co-packaged together with an opioid peptide, dynorphin, into 160 nm diameter neurosecretory vesicles in the normal rat hypothalamo-neurohypophysial system. The homozygous Brattleboro rat lacks vasopressin and vasopressin-associated neurophysin, but contains substantial amounts of dynorphin in the vasopressin-deficient neurosecretory cells. We used post-embedding electron microscopic immunocytochemistry to determine the subcellular location of dynorphin in Brattleboro rats. The results show that dynorphin is present within 100 nm neurosecretory vesicles in homozygous Brattleboro cell bodies and axons, and within 160 nm vesicles in heterozygous (control) neurosecretory cell bodies and axons. Oxytocin-associated neurophysin is present in a separate population of magnocellular neurons in both homozygous and heterozygous rats, and is contained within 160 nm vesicles in both cases. Therefore, the absence of synthesis of the vasopressin prohormone results in a dramatic reduction of neurosecretory vesicle size, despite the continued synthesis and packaging of dynorphin peptides.
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PMID:Immunocytochemical identification of dynorphin-containing vesicles in Brattleboro rats. 286 11

Binding of the opiate antagonists [3H]diprenorphine and [3H]naloxone and of the opioid agonists [3H]Met-enkephalin and [3H]dynorphin(1-8) was studied in a fraction of the rat neurohypophysis containing disconnected oxytocin and vasopressin nerve endings ('neurosecretosomes'). There was specific binding of [3H]diprenorphine in the fraction enriched with neurosecretosomes. This binding was only partially displaceable by naloxone; naloxone binding was stereospecific. Intact and unoxidized [3H]Met-enkephalin was found in the neurosecretosome pellet; binding of the analogue D-Ala-D-Leu-enkephalin was very low. Our data favour the assumption of a direct action of endogenous opioids at the neurosecretory nerve endings.
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PMID:Opioid binding in a rat neurohypophysial fraction enriched in oxytocin and vasopressin nerve endings. 286 4

The distribution of arginine-vasopressin (AVP)-, oxytocin-, beta-endorphin (beta-EP)- and dynorphin-immunoreactive cells was examined by peroxidase-antiperoxidase (PAP) immunocytochemistry in the ovaries of Brattleboro and Long-Evans (LE) rats. The ovarian distribution of the peptide-immunoreactivity is indistinguishable between the two strains. AVP- and beta-EP-immunoreactivity is co-localized in the majority of luteal cells, and in some cells scattered in the interstitial tissue. Of the AVP/beta-EP-positive cells, 1-2% also contained immunoreactive (ir)-dynorphin. Some cells in the interstitium contained only ir-AVP (approximately 50%) or only ir-dynorphin (approximately 5%); in the corpora lutea, however, no luteal cells appeared to contain only one peptide. AVP-immunoreactivity is also present in theca cells surrounding secondary and large, antral follicles; ir-oxytocin was not observed in any ovarian cell type in the rat. These data suggest that most luteal, and some interstitial, cells in the ovary have the capacity to produce and store up to three different neuropeptides.
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PMID:Co-expression of vasopressin with beta-endorphin and dynorphin in individual cells from the ovaries of Brattleboro and Long-Evans rats: immunocytochemical studies. 287 49


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