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

Electrolytic lesion of the paraventricular nucleus (PVN) of the hypothalamus blocks the tachycardia response to stress. The current study examined the effects of chemical lesion of PVN parvocellular neurons on the cardiovascular and endocrine responses to stress and on the content of hypothalamic oxytocin (OT) mRNA levels. Acute footshock stress increased heart rate in both ibotenic acid lesion and control groups of animals; however, the tachycardia was significantly lower in animals with a PVN lesion than the controls. Lesion of the PVN also attenuated the increase in plasma OT induced by stress, 4-fold in the lesion group versus 20-fold for the controls. There was not a generalized decrease in hormonal responsiveness since the OT response to an osmotic challenge was exaggerated in the lesion group. There was no difference between the groups in the arterial pressure and vasopressin responses to acute stress. Neurotoxin lesions of the PVN also resulted in significant depletions of VP and OT in all levels of the spinal cord and decreased OT levels in the dorsal brainstem. Ibotenic acid lesions of the PVN resulted in no significant changes in OT mRNA in the PVN, SON and PP. In addition, the 48-h dehydration resulted in a significant increase in plasma OT and OT mRNA in the PVN. These data indicate that the parvocellular neurons of the PVN play a role in integration of cardiovascular and endocrine responses to both stressful and osmotic stimuli and provide further evidence that parvocellular OT and VP neurons project to the brainstem and spinal cord.
 ...
PMID:Excitotoxin paraventricular nucleus lesions: stress and endocrine reactivity and oxytocin mRNA levels. 147 37

Corticotropin-releasing factor (CRF) has been reported to be expressed in oxytocin-containing magnocellular neurosecretory neurons of the paraventricular (PVN) and supraoptic (SON) nuclei, and in Barrington's nucleus, a pontine micturition center. Each of these cell groups is known to play a role in fluid and electrolyte homeostasis. To gain a better understanding of the role of CRF in this context, the effects of osmotic stimulation and volume loading on CRF mRNA levels in the PVN, SON and Barrington's nucleus were examined using in situ hybridization histochemistry with an 35S-labeled cRNA probe. Adult male rats received either normal tap water (control), or hypertonic (2%) saline (HS) for up to 3 days. In a second experiment, normal saline was infused through a jugular vein cannula at 6 ml/h for 3 days; control rats were cannulated but received no infusion. Relative levels of CRF mRNA were compared by estimating both the number of positively hybridized cells and the density of silver grains in emulsion-dipped autoradiograms. HS treatment resulted in marked increases in CRF mRNA in the magnocellular neurosecretory system. All recognized oxytocinergic cell clusters, i.e., the anterior, medial and posterior magnocellural subdivisions of the PVN, the dorsal aspect of the SON, and components of the accessory magnocellular system, displayed this effect. By contrast, HS treatment resulted in significant decreases in CRF mRNA levels in the parvocellular (hypophysiotropic) division of the PVN and in Barrington's nucleus. By contrast, volume loading, which failed to affect plasma osmolality, significantly increased CRF mRNA levels in Barrington's nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Regulation of corticotropin-releasing factor mRNA in neuroendocrine and autonomic neurons by osmotic stimulation and volume loading. 148 95

In situ hybridization histochemistry and indirect immunofluorescence histochemistry were used to study changes in the expression of vasopressin (VP), oxytocin (OXY), tyrosine hydroxylase (TH), galanin (GAL), dynorphin (DYN) and cholecystokinin (CCK) in hypothalamic magnocellular neurons of the paraventricular (PVN) and supraoptic (SON) nuclei of rats. After prolonged administration of 2% sodium chloride as drinking water (salt-loading), the treatment increased the levels of VP, OXY, TH, GAL, DYN and CCK mRNA in the PVN and SON. The increase in CCK mRNA was, however, proportionally higher in the PVN than in the SON. Within cell bodies of the PVN and SON of salt-loaded rats, a depletion of VP- and OXY-like immunoreactivity (LI) and an increase in TH-LI were seen. In salt-loaded/colchicine-treated rats, a marked decrease in GAL- and DYN-LI, but no specific changes in CCK-LI were observed. Within nerve fibers of the posterior pituitary of salt-loaded rats, a marked depletion of VP-, GAL- and DYN-LI was found. Less pronounced depletion was observed in OXY- and CCK-LI, and no specific changes in TH-LI were seen. The results show that high plasma osmolality induces increased mRNA levels for VP, OXY, TH, GAL, DYN and CCK, presumably indicating increased synthesis, an increased export from cell somata of VP, OXY, GAL and DYN, and a decrease in levels of these peptides in the posterior pituitary, suggesting increased release. The catecholamine-synthesizing enzyme TH, however, which has a cytoplasmic localization and is not released from nerve endings, remains high in the cell bodies and nerve endings during this state of increased activity.
 ...
PMID:Peptides and transmitter enzymes in hypothalamic magnocellular neurons after administration of hyperosmotic stimuli: comparison between messenger RNA and peptide/protein levels. 169 5

Sexual stimulation of males has been reported to affect hypothalamic oxytocinergic systems. In the present study we used radioimmunoassays of microdissected forebrain regions and immunocytochemical analysis of Vibratome sections to study the oxytocin systems of naive males, males killed after one mating, and males mated daily with different receptive females for 3 weeks. In males that had mated once, less oxytocin-immunoreactive neurons were observed in the paraventricular (PVN), supraoptic (SON) and periventricular (NPE) nuclei than in naive males. However, after repeated matings, the number of immunoreactive neurons and their staining intensity was increased in these regions. Furthermore, additional oxytocinergic neurons could be found in the lateral subcommissural nucleus, the zona incerta and the ansa lenticularis of repeatedly mated males. Oxytocin-immunoreactive neurons were only occasionally seen in these areas in unmated males or in animals that had been killed after initial mating. Radioimmunoassays of microdissected PVN, SON, NPE and the lateral hypothalamus confirmed the reduction in oxytocin-immunoreactive levels after a first mating by a male and the increase after repeated matings. It is likely that oxytocin secretion into peripheral and portal circulation is stimulated by the endocrine conditions associated with initial mating. These immediate effects may be followed by the activation of synthesis in oxytocin neurons in several sites of the basal forebrain.
 ...
PMID:Mating alters topography and content of oxytocin immunoreactivity in male mouse brain. 176 31

Immunocytochemical and immunoblotting technique have been used to characterize the antigens recognized by two monoclonal antibodies (MAbs C6 and D5) produced against dissociated cells from punches of neonatal supraoptic (SON) and paraventricular (PVN) hypothalamic nuclei of the rat. Peroxidase immunocytochemistry revealed that both MAbs label magnocellular perikarya in the adult and neonatal SON and PVN as well as smaller neurons in the suprachiasmatic nucleus. Axons of the hypothalamo-neurohypophysial tract are also immunolabeled within the hypothalamus and zona interna of the median eminence, and C6 and D5 each bind specifically to both the adult and neonatal neurohypophysis. Dual-label immunofluorescence experiments employing C6 or D5 simultaneously with rabbit antisera specific for either oxytocin, neurophysin or vasopressin neurophysin revealed that C6 binds only to vasopressinergic magnocellular perikarya in the SON, while D5 labels both vasopressinergic and a small subset of oxytocinergic magnocellular neurons. Post-embedding immunogold analysis of MAb binding to the neurohypophysis at the ultrastructural level showed that both C6 and D5 recognize antigens associated with large dense core neurosecretory granules in a subset of neurosecretory axons. Initial biochemical characterization of the antigens recognized by C6 and D5 was performed using SDS-PAGE and Western immunoblotting. MAbs C6 and D5 label single protein bands with apparent molecular weights of 38 and 68 kDa, resp., in blots of reduced extracts from the adult neurointermediate lobe. No cross-reactivity between C6 and D5 and the neurophysins was apparent, nor did anti-neurophysin sera recognize the bands identified by C6 and D5. We have therefore designated these novel antigens as VPGP38 and VPGP68 for VasoPressin Granule Proteins.
 ...
PMID:Monoclonal antibodies identify two novel proteins associated with vasopressin secretory granules of the rat neurohypophysis. 186 40

In order to evaluate the responses to osmotic stress of oxytocinergic neurons in vivo, we have studied oxytocin (OXY) and c-fos protein expression in the brain by means of double-immunostaining. C-fos immunoreactivity was detected in a subset of OXY neurons, as well as in other neurons non-immunoreactive for OXY, as early as 90 min after intraperitoneal injection of a hypertonic saline solution. C-fos expression was found in approx. 70% of OXY-immunoreactive neurons in the supraoptic (SON), lateral subcommisural (LSN) and paraventricular (PVN) nuclei, and not in OXY neurons in other hypothalamic areas. The expression of c-fos may be used as a means to map the circuitry by which osmotic stimulation activates OXY-containing neurons, and thus provide further insights into the functions with which OXY may be associated.
 ...
PMID:Oxytocin neurons in the rat hypothalamus exhibit c-fos immunoreactivity upon osmotic stress. 212 73

Vasopressin (VP)- and oxytocin (OXY)-producing neurons, components of the rat supraoptic nucleus, have been located with immunohistochemical methods, with the purpose of studying their morphofunctional characteristics during different phases of life (embryonic, juvenile, adult and senile). To carry out this study, an IBAS I (Kontron) computerised image analyser has been utilised. The hormone VP is first detected in the neuronal cytoplasm of 21 days old rat embryos and the hormone OXY appears in the neuronal cytoplasm later, in the newborn phase. The neuronal area with a positive reaction for the two neurohormones has been evaluated and it has been found that the quantity of reaction substance is proportional to the age. In the adult period, VP neurons possess a reaction area (198 microns 2) greater than that of OXY neurons (153 microns 2). In the SON, there are two neuronal shapes, fusiform and round; these shapes coexist in both hormonal types of neurons. Until Day 15 of postnatal development, the SON neurons are intermixed in the interior of the nucleus but in this period a neuronal redistribution is initiated. In the adult phase, OXY neurons are situated preferentially in the anterior, posterior and dorsal parts and VP neurons in the ventral and posterior parts, with both neurons being present in the intermediate part of the SON.
 ...
PMID:Morphometric study on the development of magnocellular neurons of the supraoptic nucleus utilising immunohistochemical methods. 218 86

As the first known of the mammalian brain's neuropeptide systems, the magnocellular hypothalamo-neurohypophysial system has become a model. A great deal is known about the stimulus conditions that activate or inactivate the elements of this system, as well as about many of the actions of its peptidergic outputs upon peripheral tissues. The well-characterized actions of two of its products, oxytocin and vasopressin, on mammary, uterine, kidney and vascular tissues have facilitated the integration of newly discovered, often initially puzzling, information into the existing body of knowledge of this important regulatory system. At the same time, new conceptions of the ways in which neuropeptidergic neurons, or groups of neurons, participate in information flow have emerged from studies of the hypothalamo-neurohypophysial system. Early views of the SON and PVN nuclei, the neurons of which make up approximately one-half of this system, did not even associate these interesting, darkly staining anterior hypothalamic cells with hormone secretion from the posterior pituitary. Secretion from this part of the pituitary, it was thought, was neurally evoked from the pituicytes that made the oxytocic and antidiuretic "principles" and then released them upon command. When these views were dispelled by the demonstration that the hormones released from the posterior pituitary were synthesized in the interesting cells of the hypothalamus, the era of mammalian central neural peptidergic systems was born. Progress in developing an ever more complete structural and functional picture of this system has been closely tied to advancements in technology, specifically in the areas of radioimmunoassay, immunocytochemistry, anatomical tracing methods at the light and electron microscopic levels, and sophisticated preparations for electrophysiological investigation. Through the judicious use of these techniques, much has been learned that has led to revision of the earlier held views of this system. In a larger context, much has been learned that is likely to be of general application in understanding the fundamental processes and principles by which the mammalian nervous system works.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Emerging concepts of structure-function dynamics in adult brain: the hypothalamo-neurohypophysial system. 220 17

Isolated rat paraventricular (PVN) and supraoptic (SON) nuclei were perifused in vitro and oxytocin and vasopressin releases were measured by radioimmunoassay during rest and during electrical stimulation. Stimulations at a frequency of 10 Hz (10-s bursts, every 10 s for 5 min) and an intensity of 4 mA, induced significant hormone release only with long duration pulses (10 ms). Short pulses (1 ms) applied at various frequencies (10, 20, 40 or 80 Hz) and intensities (4, 5, 10 or 20 mA) had no effect. The electrically evoked release of both hormones was not affected by tetrodotoxin (TTX), a sodium channel blocker, but was blocked in low-calcium medium or in the presence of gallopamil hydrochloride (D-600), a calcium channel blocker. These results suggest that, following electrical stimulation, oxytocin and vasopressin are released locally within the magnocellular nuclei even when blocking action potentials. The possibility of dendritic release is discussed.
 ...
PMID:Electrical stimulations of perifused magnocellular nuclei in vitro elicit Ca2+-dependent, tetrodotoxin-insensitive release of oxytocin and vasopressin. 243 5

The distribution, morphological features, and morphometric characteristics of cell bodies producing oxytocin (OT) and vasopressin (AVP) were studied in the rabbit hypothalamus by means of a conventional immunoperoxidase method. The aim of the present study was to determine the existence or not of a species-specific OT-cell group that might be involved in the dense OT innervation of the intermediate lobe in the leporidae. No OT-cell group clearly distinct from the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei was found, even in colchicine-treated animals. Most immunoreactive perikarya were found within these nuclei. In addition, small AVP neurons occurred in the suprachiasmatic nucleus. In the SON, the predominant, tightly packed AVP cells occupied the ventral part of the nucleus, whereas OT neurons were dorsolaterally located. The PVN presented a loose organization without any obvious subdivision. OT cells, which predominated, occupied the medial part of the nucleus. The PVN had a prominent rostral anterobasal extension composed mainly of OT cells. Laterally to the nucleus, numerous large AVP neurons, with few and smaller OT cells, dispersed along the neurosecretory tract without forming definite cell clusters. AVP cell bodies had a rough granular aspect contrasting with the smooth and fine one of OT cells. Spinelike processes were rarely observed on the perikarya, except on large scattered AVP neurons, but frequently covered the proximal dendrites of both types of neurons. Throughout the hypothalamus, OT neurons had definitely smaller mean somal areas and were more homogeneous in size than AVP cells.
 ...
PMID:Distribution and morphometric characteristics of oxytocin- and vasopressin-immunoreactive neurons in the rabbit hypothalamus. 276 Feb 67


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>