UNIPROT:P01178 - FACTA Search

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

The hypothalamus has been claimed to be involved in a great number of physiological functions in development, such as sexual differentiation (gender, sexual orientation) and birth, as well as in various developmental disorders including mental retardation, sudden infant death syndrome (SIDS), Kallman's syndrome and Prader-Willi syndrome. In this review a number of hypothalamic nuclei have therefore been discussed with respect to their development in health and disease. The suprachiasmatic nucleus (SCN) is the clock of the brain and shows circadian and seasonal fluctuations in vasopressin-expressing cell numbers. The SCN also seems to be involved in reproduction, adding interest to the sex differences in shape of the vasopressin-containing SCN subnucleus and in its VIP cell number. In addition, differences in relation to sexual orientation can be seen in this perspective. The vasopressin and VIP neurons of the SCN develop mainly postnatally, but as premature children may have circadian temperature rhythms, a different SCN cell type is probably more mature at birth. The sexually dimorphic nucleus (SDN, intermediate nucleus, INAH-1) is twice as large in young male adults as in young females. At the moment of birth only 20% of the SDN cell number is present. From birth until two to four years of age cell numbers increase equally rapidly in both sexes. After this age cell numbers start to decrease in girls, creating the sex difference. The size of the SDN does not show any relationship to sexual orientation in men. The large neurosecretory cells of the supraoptic (SON) and paraventricular nucleus (PVN) project to the neurohypophysis, where they release vasopressin and oxytocin into the blood circulation. In the fetus these hormones play an active role in the birth process. Fetal oxytocin may initiate or accelerate the course of labor. Fetal vasopressin plays a role in the adaptation to stress--caused by the birth process--by redistribution of the fetal blood flow. Corticotropin-releasing hormone (CRH) neurons of the PVN play a central role in stress response. Thus fetal CRH neurons may play a role in the timing of the moment of birth. Recently, alterations have been described in peptidergic, aminergic and cholinergic transmitters in the hypothalamus in SIDS. Future research will have to establish whether these changes are part of the course of SIDS. A large proportion of the SON and PVN neurons also produce tyrosine hydroxylase (TH). In neonates the majority of TH-immunoreactive neurons colocalizes vasopressin, while in the adult the majority of TH-positive neurons colocalizes oxytocin.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Development of the human hypothalamus. 764 57

In the developing and adult human paraventricular (PVN) and supraoptic (SON) nucleus, a large proportion of neurons contains the catecholamine-synthesizing enzyme tyrosine hydroxylase (TH). In the present study we investigated the possible colocalization of TH with oxytocin (OXT) or vasopressin (VP) in the adult and neonatal PVN and SON. Adjacent paraffin sections were incubated simultaneously with two antibodies: a polyclonal against TH and a monoclonal against OXT or VP and stained with a double peroxidase-antiperoxidase/alkaline phosphatase method. We observed that TH-immunoreactive(IR) perikarya in the human PVN and SON were also positive for OXT or VP. A clear difference between the neonates and adult cases of our sample was observed in the proportion of TH-IR neurons that colocalize OXT or VP. In the neonates the majority of the TH-IR perikarya was also stained for VP, while only few TH-IR neurons were also positive for OXT. The opposite was observed in the adults, where the majority of the double-stained TH-IR neurons colocalizes OXT while only few TH-IR perikarya appear to contain VP. Our study establishes the colocalization of TH with OXT or VP in the adult and neonatal PVN and SON and indicates that antemortem factors such as perinatal hypoxia might increase TH-immunoreactivity of the VP neurons in man.
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PMID:Colocalization of tyrosine hydroxylase with oxytocin or vasopressin in neurons of the human paraventricular and supraoptic nucleus. 769 71

This brief review of vasopressin (VP) and oxytocin (OT) release into the extracellular space of the supraoptic (SON) and paraventricular (PVN) nuclei focuses on recent data illustrating the significance of their intranuclear release and the potential functional consequences. With the use of in vitro techniques, it has been demonstrated that administration of exogenous OT causes local peptide release and that, in vivo, this facilitates the milk ejection reflex. These findings lead to the idea that endogenous peptides are released into the hypothalamic nuclei. Microperfusion techniques have been used to monitor the dynamics of intranuclear OT and VP release in response to distinct stimuli. It is clear that intranuclear release of OT plays a role during reproductive states (parturition and lactation) and that intranuclear release of VP and OT is involved in osmoregulation. This review discusses 1) the origin of the intranuclearly released peptides, 2) stimuli which cause release into the hypothalamic nuclei, and 3) the function of intranuclear VP and OT, e.g., regulation of local morphology, feedback mechanisms and synchronization, and the possible role in regulating autonomic function and behavior.
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PMID:Functional role of intrahypothalamic release of oxytocin and vasopressin: consequences and controversies. 773 49

Lactation is associated with complex changes of the hypothalamo-neurohypophysial system, and oxytocin released within the hypothalamic supraoptic (SON) and paraventricular nuclei may serve as a signal of communication between the magnocellular nuclei in lactating rats. In the first study, the intranuclear and peripheral release patterns of oxytocin and vasopressin in response to intraperitoneal hypertonic saline were studied in virgin and lactating rats to determine if the reduced osmoresponsiveness of the oxytocinergic and vasopressinergic systems during lactation is reflected by reduced release not only into blood, but also within the SON. Simultaneous microdialysis was performed within the SON and the jugular vein before and up to 6 hr after peripheral osmotic stimulation (3.0 M NaCl, 0.6 ml/100 gm body weight, i.p.). There was an immediate increase in secretion of both oxytocin and vasopressin into blood, whereas peptide release within the SON was delayed and peaked after 4-5 hr. Peripheral release of both peptides was significantly reduced in lactating animals, whereas within the SON release of oxytocin, but not vasopressin, was significantly reduced during lactation. In the second study, cross talk between the SONs--another phenomenon which seems to be characteristic for lactation--was studied. Microdialysis of one SON with hypertonic perfusion medium (with 1 M NaCl) significantly increased the release of oxytocin, vasopressin, and various amino acids (aspartate, glutamate, serine, glutamine, gamma amino butyric acid, and arginine) within the ipsilateral SON. In contrast to virgin female and male animals, this unilateral stimulation of the SON resulted in a transiently increased release of oxytocin in the contralateral SON of lactating rats. The release of vasopressin and amino acids within the contralateral SON of lactating rats remained unchanged, indicating specific activation of contralateral oxytocinergic neurons.
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PMID:Osmotic responsiveness and cross talk involving oxytocin, but not vasopressin or amino acids, between the supraoptic nuclei in virgin and lactating rats. 775 20

Intracerebroventricular (i.c.v.) infusions of angiotensin II (AII) reliably induced c-fos expression in the supraoptic (SON) and paraventricular (PVN) nuclei, as well as other areas of the basal forebrain including the OVLT, subfornical organ (SFO), and bed nucleus (BNST). Double-labelling showed that AII-induced c-fos was observed in both vasopressin (AVP-) and oxytocin (OXY)-containing neurons of the SON and PVN in male rats. Allowing rats to drink water after AII infusions suppressed c-fos expression both AVP- and OXY-stained magnocellular neurons. Intragastric infusions of water were also effective, showing that oro-pharyngeal stimuli were not critical. Maximal suppression occurred in rats in whom water had been infused intragastrically about 5 min before i.c.v. AII infusions, suggesting that changes in osmolarity were responsible. i.c.v. AII also induced c-fos expression in a number of brainstem structures, including the solitary nucleus (NTS), lateral parabrachial nucleus (LPBN), locus coeruleus (LC), and the area postrema (AP). These results indicate that AVP and OXY-containing neurons in the magnocellular parts of the SON and PVN alter their immediate-early gene response to AII after water intake, and that this does not depend upon oro-pharyngeal factors. Furthermore, AII can induce c-fos expression in a number of brainstem nuclei associated with autonomic function, and these do not respond to water intake.
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PMID:Regional suppression by water intake of c-fos expression induced by intraventricular infusions of angiotensin II. 782 Jun 57

Magnocellular neurons of the supraoptic (SON) and paraventricular (PVN) nuclei projecting to the neurohypophysis produce, in addition to the classical hormones vasopressin and oxytocin, a large number of other peptides, one of which is cholecystokinin (CCK). Binding sites for CCK have been identified in the posterior pituitary. Recently the cDNAs for CCKA and CCKB receptors were isolated and characterized, and CCKA and CCKB receptor mRNAs were localized in the SON and PVN. We have used complementary oligonucleotides and in situ hybridization histochemistry to study CCKB receptor mRNA in hypothalamic neurons. Changes in the expression of CCKB receptor mRNA in the SON and PVN were analysed in salt-loaded as well as in hypophysectomized animals. Levels of CCKB receptor mRNA in the PVN and SON increased markedly in salt-loaded animals as compared to controls. An increase in CCKB receptor mRNA levels was seen in the SON and PVN after 3 days of salt loading, with high levels continuing through 5 and 7 days. At 14 days, the levels of CCKB receptor mRNA in the PVN were significantly lower as compared to 7 days. Hypophysectomy 5 days prior to sacrifice, resulting in a nerve lesion in the neurohypophysial pathway and removal of the anterior pituitary hormones, induced a significant increase in CCKB receptor mRNA levels in neurons of the PVN. The increase in CCKB receptor mRNA labelling after salt loading was mainly observed in the ventrolateral part of the PVN and in the dorsolateral part of the SON, corresponding to oxytocin-containing neurons, whereas the increase after hypophysectomy was mainly seen in the central part of the PVN and in the ventral part of the SON, corresponding to vasopressin-containing neurons. The results suggest that the synthesis of CCKB receptors in magnocellular neurons is increased upon osmotic challenge and hypophysectomy.
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PMID:Cholecystokinin B receptor gene expression in hypothalamic neurosecretory neurons after experimental manipulations. 784 36

In the preceding article, a dorsochiasmatic area (DCh) was described that projects to both paraventricular (PVN) and supraoptic (SON) nuclei. The main afferents of the DCh, revealed by local injections of retrograde tracers, are the hypothalamic PVN and SON, lateral septal nuclei (LSV and SHy), bed nuclei of the stria terminalis (BST), anteroventral third ventricle region, particularly the median preoptic nucleus (MnPO), the subfornical organ, medial preoptic areas, arcuate hypothalamic nucleus, ventromedial hypothalamic nuclei, paraventricular thalamic nucleus, and, more caudally, several structures of the posterior hypothalamus and mesencephalon. The relations between DCh and BST, LSV, SHy, or MnPO appeared reciprocal. In view of their reciprocal relationships with the hypothalamo-neurohypophyseal system and some of their related extrahypothalamic structures, the DCh might be involved in the regulation of the vasopressin (AVP) and/or oxytocin (OT) systems, or in reproductive behavior.
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PMID:Evidence for reciprocal connections between the dorsochiasmatic area and the hypothalamo neurohypophyseal system and some related extrahypothalamic structures. 785 Apr 80

The purpose of the present studies was to determine whether cells in the hypothalamic paraventricular (PVN) or supraoptic (SON) nuclei mediate the serotonergic stimulation of oxytocin secretion. The serotonergic stimulus consisted of injection of the 5-HT-releasing drug p-chloroamphetamine (8 mg/kg, IP). The validity of this approach was verified by comparing this drug with another 5-HT releaser, d-fenfluramine (5 mg/kg, IP). Both 5-HT releasers increased plasma oxytocin concentration. Furthermore, the 5-HT uptake blocker fluoxetine (10 mg/kg, IP) blocked the effects of both p-chloroamphetamine and d-fenfluramine on plasma oxytocin concentrations, suggesting that both 5-HT releasers must be taken up through the 5-HT transporter into 5-HT nerve terminals to increase oxytocin secretion. In the lesion experiments, cells in the hypothalamic PVN or SON were destroyed by injection of the cell-selective neurotoxin ibotenic acid. The PVN lesions reduced basal levels and inhibited the effect of p-chloroamphetamine (8 mg/kg, IP) on plasma oxytocin concentration. In contrast, SON lesions did not alter basal oxytocin levels and did not reduce the oxytocin response to p-chloroamphetamine, suggesting that the SON is not involved in the serotonergic stimulation of oxytocin secretion. Site specificity of the PVN lesions was confirmed when injections of ibotenic acid into the hypothalamic dorsomedial nucleus (DMN), immediately caudal to the PVN, potentiated the oxytocin response to p-chloroamphetamine, suggesting that the DMN exerts an inhibitory influence on the secretion of oxytocin. Taken together, the data suggest that the serotonergic stimulation of oxytocin secretion involves PVN, but not SON, oxytocin neurons.
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PMID:Hypothalamic paraventricular, but not supraoptic neurons, mediate the serotonergic stimulation of oxytocin secretion. 788 48

Recent studies have shown that the neuropeptides arginine-8-vasopressin (AVP) and oxytocin (OXT) are released within the supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus in response to microdialysis of these nuclei with high-NaCl perfusion media. These results suggest an inherent osmosensitivity of SON and PVN neurons. To investigate whether the observed release of AVP/OXT is a unique phenomenon to these neuropeptides, several brain regions were examined for the release of amino acids or dopamine in response to high- or low-NaCl stimulation. Urethane-anesthetized male Sprague-Dawley rats were perfused with five-ion solution using U-shaped microdialysis probes. Samples were collected at 30-min intervals and analyzed for amino acids and dopamine by HPLC. In the dialysates of all perfusion areas, including the SON, PVN, hippocampus, and striatum, concentrations of Asp, Glu, Ser, Gln, Gly, taurine (Tau), and gamma-aminobutyric acid (GABA) were significantly increased during perfusion with high-NaCl medium. This release was found to be dose dependent when tested in the hippocampus and striatum with perfusion medium containing 0.5 or 1.0 M NaCl. However, only the release of Glu and Ser was found to be Ca2+ dependent. In contrast, the use of mannitol, a nonionic osmolyte, for perfusions in the striatum in concentrations of 0.5 and 1 M resulted in reduced levels of amino acids in the dialysates (Glu, Ser, Gln, and Tau). Low-NaCl perfusion medium (0.01 M) resulted in significantly increased Glu, Tau, Gly, and GABA levels in the striatum. In addition, dopamine levels in striatal dialysates were significantly increased during stimulation with 1 M NaCl. These results indicate that stimulation with high NaCl concentrations affects the release of several neurotransmitters and is not specific for AVP and OXT. The described phenomenon of the release of amino acids in response to this stimulation seems to be a response to the changed ionic concentration rather than to the osmolality. In light of these findings shown for amino acids and dopamine as well as those previously reported for AVP, OXT, and angiotensin, it would appear that sensitivity to tonicity changes brought about by microdialysis may be a feature of many transmitter systems.
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PMID:Microdialysis with high NaCl causes central release of amino acids and dopamine. 789 Oct 91

The supraoptic (SON) and paraventricular nuclei (PVN) of the human hypothalamus are production sites of vasopressin (AVP) and oxytocin (OXT). Although the hypothalamus is affected in Alzheimer's disease (AD), previous work has not only shown that in these two nuclei no neurons are lost, neither during aging nor in AD, but that the number of AVP-expressing neurons and their nucleolar size had even increased with age. These observations indicated that the peptide synthesis of the AVP neurons was activated in the oldest age-groups. Recently published, qualitative observations, using the area of the Golgi Apparatus (GA) as a sensitive parameter for neurosecretory activity, confirmed the activation of SON and PVN neurons with age in human; however, in this report the neurons were not identified according to their neuropeptide content. In the present quantitative study we determined whether the AVP neurons were indeed activated as a result of the aging process in controls and AD patients. We applied a polyclonal antiserum directed against the medial cisternae of the GA on formalin-fixed, paraffin-embedded tissue sections taken from the dorsolateral SON (dl-SON) of 10 controls and 10 AD patients, and performed our measurements in this area that is known to be predominantly occupied (90-95%) by AVP neurons. In addition, the sparse OXT cells present in the area of study, were excluded from the measurements on the basis of alternative sections stained for OXT. In the dl-SON, the area occupied by the GA and the cellular profile area per patient were quaNtified by means of image analysis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation of vasopressin neurons in aging and Alzheimer's disease. 789 70

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