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

Maternal behaviour and the ewe's ability to recognize her lamb depend on olfactory cues and parturition, and are facilitated by maternal experience. Parturition induces a variety of neurochemical changes in the brain and, in particular, oxytocin (OT) release. This peptide injected centrally induces maternal behaviour. Oxytocin release occurs in the olfactory bulb (OB) at parturition and yet this structure is involved in the process of selective bonding with lamb. The present study therefore investigated the possibility that oxytocin release in the OB might modulate the release of classical transmitters that are known to be important in controlling selective recognition and whether maternal experience has any effect on this. We have first used in vivo microdialysis to measure OT release, as well as that of the related peptide, arginine-vasopressin (AVP), in the OB of maternally experienced and inexperienced ewes during parturition. While OT release significantly increased in both primiparous and multiparous ewes at parturition this increase was significantly greater in multiparous ewes. No significant change of AVP release was observed in either group. However, vagino-cervical stimulation (VCS) performed at 6 h post-partum caused similar increases in OT but not AVP release in both primiparous and multiparous ewes suggesting that the first birth experience potentiates the ability of VCS to evoke OT release within 6 h of parturition. Using retrodialysis, either OT (10 microM) or AVP (10 microM) were infused into the OB of multiparous and nulliparous ewes and their effects on modulating acetylcholine (ACh), noradrenaline (NA), glutamate and gamma-aminobutyric acid (GABA) release were monitored. Both peptides produced an increase of ACh and NA in multiparous animals and this effect was either absent or less pronounced in nulliparous animals. OT, but not AVP, also increased GABA release equivalently in nulliparous and multiparous animals. Glutamate release was not altered in response to OT or AVP infusion. These results suggest that OT release in the OB at parturition may facilitate the recognition of lamb odours by modulating NA, ACh and GABA release which are of primary importance for olfactory memory. The reduced release of OT in the OB of primiparous ewes at parturition, together with its reduced ability to modulate NA and ACh release, might also partly explain why maternally inexperienced animals require a longer period to selectively bond with their lambs.
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PMID:Oxytocin and vasopressin release in the olfactory bulb of parturient ewes: changes with maternal experience and effects on acetylcholine, gamma-aminobutyric acid, glutamate and noradrenaline release. 771 75

Relaxin is a polypeptide hormone best known for its role in parturition. However, high affinity relaxin receptors have been localized in the rat brain and heart in addition to the uterus. Several lines of evidence also suggest that relaxin may be involved in the regulation of blood pressure, heart rate, and the release of oxytocin and vasopressin. We now show by Northern analysis that a 1-kilobase relaxin transcript is detected in the rat brain as well as the ovary of pregnant rats. Using in situ hybridization, relaxin mRNA is localized in discrete regions of the male and female brains, including the anterior olfactory nucleus, tenia tecta, pyriform cortex, neocortex, and hippocampus. Developmental studies show that relaxin mRNA is present in the 1-day postnatal brain, while relaxin receptors are not detectable until 7 days after birth. The relaxin receptor binding affinity was similar in the developing brains, but there was a steady increase in relaxin binding sites during postnatal days 7 to 29, suggesting that relaxin may play a role in brain maturation. While relaxin mRNA is not detected in the heart, high levels of relaxin receptors are detected in the cardiac atrium as early as 1 day after birth. These atrial receptors remained at similar levels throughout postnatal development, suggesting an important role for relaxin in cardiovascular function.
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PMID:Expression of relaxin mRNA and relaxin receptors in postnatal and adult rat brains and hearts. Localization and developmental patterns. 839 68

Localization of oxytocin- and vasopressin-binding sites has so far been studied in the rat brain by means of film autoradiographs. The disposal of iodinated ligands with high specificity has allowed us to develop histoautoradiography on emulsion-coated sections and to reinvestigate on a microscopic scale the distribution of these sites in the telencephalon (septum, striatopallidal system, amygdala and hippocampus). This technique showed that oxytocin and vasopressin labelling presented distinct distributions and coincided with delimited zones, corresponding to anatomical subdivisions defined on cytoarchitectural and immunocytochemical bases. Vasopressin sites were seen in the dorsal and intermediate parts of the lateral septum and the juxtacapsular nucleus of the bed nucleus of the stria terminalis. Oxytocin sites were located in the ventral and intermediate parts of the lateral septum, the oval and the principal nuclei of the bed nucleus of the stria terminalis and the septofimbrial nucleus. In the striatopallidal system, vasopressin sites were found in the accumbens nucleus and the fundus striati, whereas oxytocin sites were in the accumbens nucleus, the head, and the posterolateral parts of the caudate-putamen, the striatal cell bridges, and the olfactory tubercle. In the amygdala, vasopressin sites were not found, but oxytocin sites were located in the central, medial, and basomedial nuclei. In the hippocampus, vasopressin sites were located in the dentate gyrus (polymorph and molecular layers), and oxytocin sites, in the subiculum (molecular and pyramidal layers) and in the field CA1 of Ammon's horn (lacunosum moleculare and pyramidal layers). The localization of the binding sites at the microscopic level permitted us to reinvestigate whether or not correlation existed in a same area between innervation, electrophysiological effects, and presence of binding sites.
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PMID:Histoautoradiographic detection of oxytocin- and vasopressin-binding sites in the telencephalon of the rat. 839 91

The effects of pregnancy, parturition and lactation and exogenous treatments with oestradiol and progesterone on oxytocin (OXY) immunoreactivity and gene expression in the sheep brain were investigated. Immunocytochemistry was used to demonstrate that increased OXY-immunoreactivity occurred in cells of the paraventricular (PVN) and supraoptic nuclei (SON), the bed nucleus of the stria terminalis (BNST), the anterior commissural nuclei (ACN) and the periventricular part of the medial preoptic area (PvMP). Oxytocin immunoreactive terminals were also seen in the accessory olfactory nucleus, the glomerular and peri-glomerular layers of the olfactory bulb, the lateral septum, the zona incerta and the pars compacta of the substantia nigra. Compared to ovariectomized and late pregnant animals, the intensity of immunoreactivity was increased in all of these oxytocinergic elements at parturition, during lactation and following exogenous treatment with oestradiol. The OXY-immunoreactivity was also more intense in late pregnant animals compared to ovariectomized ones. Quantitative in situ hybridization histochemistry showed that cells in the PVN, SON, BNST and PvMP all showed significantly increased expression of OXY mRNA in animals at parturition and during lactation compared to late pregnant or ovariectomized animals. Expression levels in late pregnant animals were also significantly higher than in ovariectomized ones. Progesterone treatment significantly increased OXY mRNA in the PVN, SON, BNST and PvMP whereas oestradiol treatment was only effective in the PVN, BNST and PvMP. Combined treatment with these steroids did not significantly increase OXY mRNA levels in comparison with their administration alone. These results show that OXY-immunoreactivity and mRNA expression are at their highest in the sheep brain when maternal behaviour is induced. The increased synthesis/storage of the peptide at parturition may be due to changes in circulating concentrations of both progesterone and oestradiol during late pregnancy.
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PMID:Changes in oxytocin immunoreactivity and mRNA expression in the sheep brain during pregnancy, parturition and lactation and in response to oestrogen and progesterone. 840 67

Social transmission of information was tested in a procedure in which a rat (Observer) could demonstrate preference for a flavored tea as drinking solution that a con-specific (Demonstrator) had consumed just prior to a period of social interaction between the two animals. The cue in this procedure, probably olfactory in nature, was remembered for a relatively short period of time. It was prolonged when the Observers were treated with dresglycinamide[Arg8]-vasopressin (DGAVP) or oxytocin immediately after the encounter with the Demonstrator. DGAVP was effective after the injection of 15 micrograms.kg-1 but not of 1.5 ng.kg-1. Oxytocin induced the effect in doses ranging from 1.5 ng.kg-1 to 15 micrograms.kg-1. A dose of 0.15 ng.kg-1 was inactive. The influence of the peptides was cue specific. It is concluded that DGAVP and oxytocin facilitate social transmission of information, as previously found for social recognition.
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PMID:Social transmission of flavored tea preferences: facilitation by a vasopressin analog and oxytocin. 844 34

Central oxytocin (OT) receptors were labelled in 3-month-old and 20-month-old rats with an iodinated OT antagonist. Comparison of the autoradiograms by quantitative image analysis revealed in the old animals a significant reduction of binding in three regions; the number of labelled OT receptors was decreased by 90% in the head of the caudate putamen, by 68% in the olfactory tubercle, and by 41% in the ventromedial hypothalamic nucleus. Previous studies had shown that the expression of OT receptors in the olfactory tubercle and in the ventromedial hypothalamic nucleus was dependent upon gonadal steroids. Therefore we hypothesize that the reduced number of OT receptors in the latter two structures of aged rats was the consequence of the 4-fold decrease of plasma testosterone that we found in this age. Another mechanism may be responsible for the marked reduction of OT receptors in the caudate putamen.
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PMID:Reduced binding of oxytocin in the rat brain during aging. 858 97

Follistatin (FS), which binds to the inhibin/activin beta A- or beta B-subunit is localized with and modulates the biological actions of activin in many systems. However, in contrast to the wide distribution of the activin beta-subunit proteins and messenger RNAs (mRNA) in the brain, demonstration of FS mRNA signal has been limited to the olfactory tubercle and layer II of the frontal cortex. We have hypothesized a more extensive distribution of central FS gene expression and localization in regions coinciding with inhibin/activin beta-subunits and possible activin-mediated effects. In the present study, we examined the central distribution of FS mRNA expression in the normal adult male rat. With in situ hybridization analysis, using a 33P-labeled RNA probe specific for rat FS, gene expression is shown to be widely distributed throughout the brain. Abundant FS mRNA expression is localized in several areas of the olfactory bulb as well as the frontal cortex, a few thalamic nuclei, and in septal regions. Moderate FS mRNA is observed in the caudate putamen and various hypothalamic areas including the paraventricular, ventromedial, dorsomedial, and arcuate nuclei. Several brain stem regions are also found to express FS mRNA, including the medial vestibular and solitary tract nuclei. Notably, FS mRNA, including the medial vestibular and solitary septal/diagonal band region is localized in patterns that are highly correlative with those of GnRH gene expression and hence may serve to regulate possible activin-mediated effects in these areas. FS mRNA is also expressed in areas associated with the activin-oxytocin pathway (solitary tract nucleus and paraventricular nucleus) and is therefore in a position to modulate the role of activin in the solitary tract nucleus-paraventricular nucleus pathway (afferent system mediating the milk-ejection reflex). The results suggest that FS is centrally localized in sites compatible with a role in the regulation of central reproductive functions.
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PMID:Distribution of follistatin messenger ribonucleic acid in the rat brain: implications for a role in the regulation of central reproductive functions. 861 60

The effects of electrical stimulation of the hypothalamus paraventricular nucleus on the spontaneous firing of mitral and granule cells in the main olfactory bulb were examined in ovariectomized female rats under urethane anaesthesia. High-frequency stimulation (0.5-1.0 mA, 10-20 pulses at 100 Hz) of the paraventricular nucleus produced inhibitory responses in 80% of mitral cells tested and excitatory responses in 74% of granule cells tested, with latencies ranging from 2 to 150 s. Both responses were blocked by infusions into the olfactory bulb of [d(CH2)5, Tyr(Me)2]ornithine-vasotocin (10 pmol), an oxytocin antagonist, and mimicked by intracerebroventricular infusions (0.2 or 0.4 nmol) or microiontophoretic applications of oxytocin but not by intracerebroventricular infusions of vasopressin (1 or 2 nmol). Infusions of 0.5% lignocaine, a local anaesthetic, into either the medial olfactory tract or the medial forebrain bundle failed to block the responses of mitral and granule cells to the stimulation. Unilateral transections at various levels between the bulb and the paraventricular nucleus also failed to block the responses. There were cases in which significant responses of mitral and granule cells to the stimulation required 60 or more pulses after the lignocaine infusions or transections, however. These results suggest that oxytocin originating in the hypothalamic paraventricular nucleus reaches the olfactory bulb following its release partly into the cerebrospinal fluid and acts to decrease olfactory processing.
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PMID:The action of oxytocin originating in the hypothalamic paraventricular nucleus on mitral and granule cells in the rat main olfactory bulb. 873 30

Expanding on research showing that oxytocin originating in the hypothalamic paraventricular nucleus acts to decrease olfactory processing at the level of the olfactory bulb, we explored the importance of oxytocin acting on the olfactory bulb for the onset of maternal behaviour in Wistar rats. Experiment I was designed to test whether spontaneous maternal behaviour following natural delivery is blocked by bilateral infusions of a low dose (5 fmol) of the oxytocin antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]ornithine-vasotocin into the olfactory bulb immediately after the delivery of the first pup and again just before a test for maternal behaviour. Intrabulbar infusions of the antagonist markedly delayed the occurrence of all components (retrieval, licking, nest building, crouching) of maternal behaviour, whereas intracerebroventricular infusions of the antagonist were without effect on any component as compared with intrabulbar infusions of saline. Experiment 2 was undertaken to determine whether infusions of oxytocin into the bulb induce a rapid onset of maternal behaviour in virgin rats. Forty-eight hours before pup presentation virgins were ovariectomized and treated with oestradiol benzoate. Immediately before pup presentation a low dose (20 pmol) of oxytocin or saline was infused bilaterally into the bulb or lateral ventricle. Intrabulbar infusions of oxytocin induced full maternal behaviour in half of the animals tested within 2 h of pup exposure, in contrast to the ineffectiveness of intracerebroventricular infusions of oxytocin and intrabulbar infusions of saline. These results suggest that the olfactory bulb is a critical site where oxytocin acts to induce a rapid onset of maternal behaviour.
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PMID:The olfactory bulb: a critical site of action for oxytocin in the induction of maternal behaviour in the rat. 873 31

The embryonic and postnatal localizations of oxytocin receptor mRNA in the developing rat brain were studied by in situ hybridization histochemistry. The hybridization signal was first detected at embryonic-day 13 in the primordium of the dorsal motor nucleus of vagus. Other positive regions progressively appeared after this time. The developmental profile of oxytocin receptor gene expression could be classified into two types; transient expression and constant abundant expression. The caudate putamen, cingulate cortex, the anterior thalamic nuclei, and the ventral tegmental area belonged to the first type. In these regions, oxytocin receptor mRNA was expressed intensely only during the early postnatal period. The regions such as the anterior olfactory nucleus, tenia tecta, some amygdaloid nuclei, piriform cortex, the ventromedial hypothalamic nucleus, subiculum, the prepositus hypoglossal nucleus and the dorsal motor nucleus of vagus showed constant expression of oxytocin receptor mRNA at high levels throughout development and in the adult. These findings concurred well with those of the ontogenic studies using receptor binding autoradiography with a ligand specific to oxytocin. Thus, the transient expression of oxytocin receptor during development was regulated at the transcriptional level in several brain regions, and oxytocin may play a role in brain development as well as in neural transmission in the mature brain.
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PMID:Differential expression of oxytocin receptor mRNA in the developing rat brain. 881 48


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