Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nitric oxide (NO) is known to regulate the release of arginine-vasopressin (AVP) and oxytocin (OT) by the paraventricular nucleus (PVN) and the supraoptic nucleus (SON). The aim of the current study was to identify in these nuclei the NO-producing neurons and the NO-receptive cells in mice. The determination of NO-synthesizing neurons was performed by double immunohistochemistry for the neuronal form of NO synthase (NOS), and AVP or OT. Besides, we visualized the NO-receptive cells by detecting cyclic GMP (cGMP), the major second messenger for NO, by immunohistochemistry on hypothalamus slices. Neuronal NOS was exclusively colocalized with OT in the PVN and the SON, suggesting that NO is mainly synthesized by oxytocinergic neurons in mice. By contrast, cGMP was not observed in magnocellular neurons, but in GABA-, tyrosine hydroxylase- and glutamate-positive fibers, as well as in GFAP-stained cells. The cGMP-immunostaining was abolished by incubating brain slices with a NOS inhibitor (L-NAME). Consequently, we provide the first evidence that NO could regulate the release of AVP and OT indirectly by modulating the activity of the main afferents to magnocellular neurons rather than by acting directly on magnocellular neurons. Moreover, both the NADPH-diaphorase activity and the mean intensity of cGMP-immunofluorescence were increased in monoamine oxidase A knock-out mice (Tg8) compared to control mice (C3H) in both nuclei. This suggests that monoamines could enhance the production of NO, contributing by this way to the fine regulation of AVP and OT release and synthesis.
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PMID:The effects of nitric oxide on magnocellular neurons could involve multiple indirect cyclic GMP-dependent pathways. 1258 Nov 64

Medullary catecholamine and hypothalamic neurosecretory oxytocin cells are activated by hypotension, but previous studies have provided uncertain outcomes concerning their ability to respond to a purely hypovolaemic stimulus. In the present study, injections of PEG/water and pentolinium were used to elicit non-hypotensive, isosmotic hypovolaemia and isovolaemic, isosmotic hypotension, respectively, in conscious rats. Animals were sacrificed 2 h after treatment. Immunolabelling for Fos, tyrosine hydroxylase and oxytocin established that these two stimuli activate almost identical populations of catecholamine neurons in the ventrolateral and dorsomedial medulla, and very similar populations of oxytocin cells in the supraoptic and paraventricular nuclei of the hypothalamus.
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PMID:Catecholamine and oxytocin cells respond to hypovolaemia as well as hypotension. 1296 Jul 71

We have studied the organization of the hypothalamus in an Australian diprotodontid metatherian mammal, the wallaby ( Macropus eugenii), using cytoarchitectural, histochemical and immunohistochemical techniques. Coronal sections of adult brains were processed for Nissl staining, histochemical reactivity (cytochrome oxidase, nicotinamide adenine dinucleotide phosphate diaphorase and acetylcholinesterase) and immunohistochemistry (antibodies to tyrosine hydroxylase, calbindin, calretinin, non-phosphorylated neurofilament protein, oxytocin and vasopressin). The distribution of immunoreactive neurons for these substances was mapped with the aid of a computer-linked microscope. In general, the wallaby hypothalamus showed a similar nuclear organization to that seen in rodents. The paraventricular nucleus could be divided into several subdivisions based on the different cellular parcellation, similar to that described in rodents. The ventromedial hypothalamic nucleus had cell-sparse dorsomedial and cell-dense ventrolateral subdivisions as seen in eutheria, suggesting a similar functional compartmentalization in all theria. The positions of tyrosine hydroxylase-positive neurons in the wallaby hypothalamus were also similar to those in eutheria. Oxytocin and vasopressinergic neurons were found in all the same major nuclear groups as seen in eutheria, although a nucleus circularis could not be identified. The general similarities between wallaby and eutherian hypothalamus indicate that the basic chemo- and cytoarchitectural features of the hypothalamus are common to eutheria and metatheria and validate the use of the wallaby as a mammalian model of wide applicability in investigations of hypothalamic functional development.
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PMID:Cyto- and chemoarchitecture of the hypothalamus of a wallaby ( Macropus eugenii) with special emphasis on oxytocin and vasopressinergic neurons. 1451 76

This study was aimed to evaluate the reaction of the vasopressin (VP) and oxytocin (OT) neurons of the supraoptic nucleus (SON) in rats to single or repeated hypergravity (HG). Special attention was paid to the tyrosine hydroxylase (TH) expression in VP neurons as a marker of the neuron activation. Rats were revolved in a centrifuge with overloading 2G for 5 days or 34 days as well as for 34 days plus 5 days with an interval of 39 days between two rotations. Control rats were kept in a centrifuge room. Radioimmununoassay, quantitative and semi-quantitative immunocytochemistry and in situ hybridization were used to evaluate: a) VP concentration in the pituitary posterior lobe (PL) and in plasma; b) the number of VP-, OT- and TH-immunoreactive neurons in the SON; c) the optic density of VP-, OT- and TH-immunoreactive materials in cell bodies (SON) and distal axons (PL), d) the optic density of VP and OT mRNAs signals (S35) in the whole SON on microfilms. According to our data, VP neurons were strongly activated during HG (5 days or 34 days) that was manifested in the functional hypertrophy of the neurons, greatly increased concentrations of VP mRNA in the SON and VP in plasma, the onset of the TH expression. The neurons showed initially (5 days) the functional insufficiency (VP release > VP synthesis) followed by their adaptation (subsequent 29 days) to the increased need in VP (VP release < VP synthesis). No reaction of VP neurons was observed to repeated HG. In contrast to VP neurons, OT neurons did not react to short-term HG or showed functional depression after the long-term treatment.
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PMID:Influence of hypergravity on hypothalamic vasopressin and oxytocin neurons in rats. 1470 80

The quantity and topography of activated vasopressin (AVP), oxytocin (OXY), and tyrosine hydroxylase (TH) neurons were studied immunohistochemically in the anterior, middle, and posterior portions of the PVN and SON in mice 60 min after a single injection of hypertonic saline (HS, 400 microl 1.5M, i.p.). Fos-neuropeptide double-stainings revealed: (1) Fos expression in each portion of the PVN and SON; (2) maximal number of Fos-AVP (79 cells) and Fos-OXY (50 cells) double-labelings in the middle portion of the PVN; (3) low number of Fos-TH perikarya in the PVN and their lack in the SON; (4) similar incidence (around 50%) of Fos-AVP and Fos-OXY perikarya in the SON; and (5) presence of activated AVP, OXY, and TH neurons in the periventricular, subependymal, and sub-PVN zones of the PVN. Topographic analysis revealed that the majority of AVP neurons expressing Fos occupied the dorsolateral and central part of the middle portion of the PVN. In the same PVN portion, Fos-OXY neurons occurred in similar frequency, however, they were primarily distributed along the lateral and medial margins of the PVN. In the SON, Fos-OXY cells occupied mainly its dorsal, while Fos-AVP cells predominated in its ventral part. The data clearly indicate that HS is not a selective stimulus neither for PVN nor SON itself and provide evidence that both PVN and SON AVP and OXY cells play important role in the mediation of signals induced by HS. In addition, the limited number of AVP, OXY, and TH neurons activated by HS may account for their differential functional specializations selective for stress/osmotic circuits activated by HS.
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PMID:Fos protein expression in mouse hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei upon osmotic stimulus: colocalization with vasopressin, oxytocin, and tyrosine hydroxylase. 1523 1

Hatano high-avoidance (HAA) and low-avoidance (LAA) animals were originally selected from Sprague-Dawley rats for good and poor active avoidance learning in a shuttle box. We studied the endocrinological profile in lactating rats to determine the effect of suckling during mid-lactation in HAA and LAA rats. The pups were separated from their mother rats 6 h before the onset of suckling and blood samples were drawn from unanaesthetized mother rats via a jugular cannula at 0, 5 and 15 min after the suckling stimulus and then 15, 45 and 105 min after pups were removed. Plasma concentrations of oxytocin in HAA rats were significantly higher than in LAA rats during the suckling period. Plasma concentrations of prolactin and ACTH in HAA rats were significantly higher than in LAA rats during the suckling period, and at 15 min and 45 min after the pups were removed. However, there were no strain differences in circulating corticosterone between the two lines, indicating that the response of the hypothalamo-pituitary axis to the suckling stimulus was greater in HAA rats than in LAA rats, whereas the ACTH-induced adrenal response of corticosterone release was higher in LAA rats than in HAA rats. Since dopamine from the median eminence inhibits prolactin secretion from the lactotrophs of the anterior pituitary, and tuberoinfundibular dopaminergic neurones are partially regulated by the level of circulating prolactin, we evaluated the activity of tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine biosynthesis. TH, measured by the accumulation of 3,4-dihydroxyphenylalanine, was significantly higher in HAA rats than in LAA rats before the suckling stimulus. After the suckling stimulus, TH activity in HAA rats was significantly lower than before suckling, whereas TH activity in LAA rats was not changed. These findings clearly demonstrated that apparent differences between the two Hatano lines exist in endocrinological profiles during suckling. These strain differences probably originate from neurotransmitter changes, such as dopamine.
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PMID:Endocrinological responses during suckling in Hatano high- and low-avoidance rats. 1528 87

Galanin is a 29-amino acid peptide widely distributed in the central nervous system of vertebrates. The organization of galaninergic systems is well known in teleosts, the most advanced actinopterygians, but no data are available on primitive bony fish. To extend the evolutionary analysis of galaninergic systems we studied the distribution of galanin-like immunoreactive (GAL-ir) cells and fibers in the sturgeon brain, since chondrosteans are among the most primitive extant actinopterygians. Double-immunolabeling experiments were performed to compare the distribution of galanin with that of neurophysin, tyrosine hydroxylase, and serotonin. Numerous GAL-ir cells of cerebrospinal fluid-contacting (CSF-C) type were found in the ventral telencephalon, preoptic area, and in the tuberal and caudal hypothalamus. The distribution of GAL-ir elements in the sturgeon brain shows many similarities to that observed in other vertebrates, but also important differences, such as the abundance of GAL-ir CSF-C cells, which appear to be a primitive characteristic. GAL-ir neurons observed in the sturgeon telencephalic hemispheres perhaps represent the basic organization of common ancestors of bony fishes and tetrapods. In the preoptic-hypophyseal system, GAL-ir cells appeared to be related not only with neurophysin-expressing neurons (in the tuberal hypothalamus) but also with serotoninergic and catecholamines-synthesizing neurons (in preoptic and tuberal nuclei). Numerous GAL-ir fibers were observed in the median eminence and neural lobe of the hypophysis, indicating that galanin may play a role in the modulation of hypophyseal secretion. GAL-ir neurons were absent from the sturgeon brainstem, suggesting that their presence in other vertebrates could represent an evolutionary recent acquisition.
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PMID:Distribution of galanin-like immunoreactivity in the brain of the Siberian sturgeon (Acipenser baeri). 1586 61

In order to establish the involvement of particular neurochemical brain groups in the response to blood volume expansion, we analyzed Fos-labeling in combination with immunolabeling for serotonin, tyrosine hydroxylase, vasopressin and oxytocin, 90 min after a sham or i.v. isotonic blood volume expansion (BVE) in unanesthetized, unrestrained rats. We also examined the changes in concentration of oxytocin, atrial natriuretic peptide and vasopressin plasma, induced by blood volume load, to confirm our previous studies. The results demonstrate the participation of specific paraventricular and supraoptic nucleus groups of cells (oxytocinergic-vasopressinergic), serotoninergic dorsal raphe nucleus cells and catecholaminergic A1/A2/A6 groups (in the caudal ventrolateral medulla, nucleus of the solitary tract and locus coeruleus respectively), in the regulatory response to BVE. They provide detailed neuroanatomical evidence to support previous observations showing the contribution of these neurochemical systems in the neural, behavioral and endocrine response to isotonic BVE.
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PMID:Neurochemical brain groups activated after an isotonic blood volume expansion in rats. 1588 15

Neuropeptide B (NPB) is a recently identified endogenous ligand for the orphan G protein-coupled receptors GPR7 and GPR8. NPB mRNA is expressed in the human, rat, and mouse brain. With the use of an antiserum directed against the rat NPB, immunoreactivity to NPB (irNPB) was detected in several discrete areas of the hypothalamus and midbrain. In the hypothalamus, irNPB cells were present in the medial preoptic area and nucleus, ventromedial preoptic nucleus, retrochiasmatic nucleus, paraventricular hypothalamic nucleus, supraoptic nucleus, accessory neurosecretory nuclei, periventricular hypothalamic nucleus, dorsomedial hypothalamic nucleus, supraoptic retrochiasmatic nucleus, lateral hypothalamic area, posterior hypothalamic area, dorsal hypothalamic area, and zona incerta. A few irNPB perikarya were noted in the arcuate nucleus, whereas a dense network of nerve fibers was present in the median eminence. In the midbrain, irNPB somata were noted in the substantia nigra (compact, reticular, medial, and lateral parts), paranigral nucleus, ventral tegmental area, interfascicular nucleus, and dorsal raphe nucleus. Neurons in the Edinger-Westphal were strongly labeled. Labeled cells were not detected in the cortex, medulla oblongata, and spinal cord; few lightly labeled cells were occasionally seen in the hippocampus. Double labeling the hypothalamic sections with NPB antiserum and vasopressin or oxytocin antibody revealed that a population of vasopressin- but not oxytocin-immunoreactive cells was irNPB. Tyrosine hydroxylase-positive neurons in the midbrain, presumably dopaminergic, were irNPB. The distribution of irNPB neurons in several areas of the hypothalamus and midbrain together with the colocalization with vasopressin or tyrosine hydroxylase suggests that the peptide may subserve neuroendocrine, autonomic, and motor functions.
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PMID:Neuropeptide B immunoreactivity in the central nervous system of the rat. 1591 Jul 74

The monotremes are an intriguing group of mammals that have major differences in their reproductive physiology and lactation from therian mammals. Monotreme young hatch from leathery skinned eggs and are nourished by milk secreted onto areolae rather than through nipples. Parturition and lactation are in part controlled through the paraventricular and supraoptic nuclei of the hypothalamus. We have used Nissl staining, enzyme histochemistry, immunohistochemistry for tyrosine hydroxylase, calbindin, oxytocin, neurophysin and non-phosphorylated neurofilament protein, and carbocyanine dye tracing techniques to examine the supraoptic and paraventricular nuclei and the course of the hypothalamo-neurohypophysial tract in two monotremes: the short-beaked echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus). In both monotremes, the supraoptic nucleus consisted of loosely packed neurons, mainly in the retrochiasmatic position. In the echidna, the paraventricular nucleus was quite small, but had similar chemoarchitectural features to therians. In the platypus, the paraventricular nucleus was larger and appeared to be part of a stream of magnocellular neurons extending from the paraventricular nucleus to the retrochiasmatic supraoptic nucleus. Immunohistochemistry for non-phosphorylated neurofilament protein and carbocyanine dye tracing suggested that hypothalamo-neurohypophysial tract neurons in the echidna lie mainly in the retrochiasmatic supraoptic and lateral hypothalamic regions, but most neurophysin and oxytocin immunoreactive neurons in the echidna were found in the paraventricular, lateral hypothalamus and supraoptic nuclei and most oxytocinergic neurons in the platypus were distributed in a band from the paraventricular nucleus to the retrochiasmatic supraoptic nucleus. The small size of the supraoptic nucleus in the two monotremes might reflect functional aspects of monotreme lactation.
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PMID:The hypothalamic supraoptic and paraventricular nuclei of the echidna and platypus. 1680 8


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