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

Pregnant rats were implanted with subcutaneous minipumps to deliver either naloxone or saline. The time-course of subsequent parturition was different between the two groups: the interval between successive births was significantly shorter for the naloxone-treated rats. This supports the hypothesis that the opioid innervation of the neurohypophysis, which is known to influence oxytocin release profoundly, has a physiological role in parturition. To test the further hypothesis that this role is particularly important in a stressful environment, pregnant rats, again implanted with minipumps, were regularly transferred, at 15-min intervals beginning with the birth of the first pup, between their normal cage and the unfamiliar environment of a glass observation chamber. No difference was noted between the time-courses of parturition for the naloxone- and saline-treated groups, although the time-courses were markedly altered from those observed in rats not subjected to an unfamiliar environment. We conclude that opioid modulation of oxytocin release may play a role in 'spacing' the delivery of successive births during normal parturition.
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PMID:Central opioids: a possible role in parturition? 316 Aug 3

Blood samples were taken from conscious, chronically-catheterized rats during parturition for measurement of oxytocin by specific radioimmunoassay. After the birth of the 3rd pup, rats were allowed to remain in their nesting cage (undisturbed rats) or were transferred for 45 min to a glass bowl (disturbed rats); at the time of transfer, rats were given an i.v. injection of the opioid antagonist naloxone or saline vehicle. Subsequent parturition was prolonged in saline-treated disturbed rats, but not in naloxone-treated disturbed rats. Parturition was significantly hastened in naloxone-treated undisturbed rats. Naloxone injections were followed by a large rise in plasma oxytocin concentrations in disturbed and undisturbed rats. We conclude, from a statistical analysis of the relationship within experimental groups between plasma oxytocin concentration and speed of parturition, that the effects of disturbance and of naloxone upon parturition may be accounted for, at least in part, by their effects upon oxytocin release. However, the effects of disturbance on parturition may not be mediated entirely by activation of opioid pathways. Naloxone did not potentiate oxytocin release in non-pregnant rats, or on Day 1 post partum, but did potentiate oxytocin release on Day 22 of pregnancy even in rats before the onset of parturition. Endogenous opioid pathways regulating oxytocin release therefore appear to be active during late pregnancy and during parturition itself.
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PMID:Endogenous opioid actions and effects of environmental disturbance on parturition and oxytocin secretion in rats. 318 53

Nulliparous female Sprague-Dawley rats, cannulated in the left lateral ventricle, were ovariectomized and estrogen primed, then either rendered anosmic via intranasal irrigation with zinc sulfate or left with intact olfaction. Forty-eight hr later, after a 2-hr habituation to the test cage, these animals were injected with either intracerebroventricular oxytocin (400 ng in 2 microliter saline) or saline (2 microliter). Only the group receiving both zinc sulfate and oxytocin became maternal. Additionally, approximately one third of the olfaction-intact rats and none of the anosmic rats cannibalized the rat pups. These results are discussed in regard to discrepancies in the literature regarding oxytocin's role in inducing maternal behavior, as well as the functional connection of the olfactory and oxytocin systems.
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PMID:The ability of oxytocin to induce short latency maternal behavior is dependent on peripheral anosmia. 360 16

The maternal behaviour of 7 ovariectomized, oestrogen-treated ewes was recorded after intracerebroventricular (ICV) infusions of oxytocin (OT). At weekly intervals 10-min behaviour tests were given starting 1 min after control (saline) or OT infusions. In the ewes' home pens, 5-, 10- and 20-micrograms doses of OT significantly increased the frequency of some or all of the maternal behaviours scored (low-pitch bleats, sniffing, licking and approaching/following the lamb), and 3 ewes allowed suckling attempts. Aggressive (head butts) and negative (withdrawal from the lamb) behaviours significantly decreased in frequency. Vaginocervical stimulation (10 min duration) produced similar effects on these behaviours. When the lambs were removed from the ewes' pens, the ewes exhibited significantly more high-pitch bleats (protest) following OT treatment. When 20 micrograms OT was given ICV in the absence of oestrogen priming, or when it was given intravenously with oestrogen priming, no significant effects on maternal behaviour were seen. Maternal behaviour was also significantly stimulated in oestrogen-treated ewes in a larger, novel testing environment (an enclosed area of field) following 5- and 20-micrograms doses of OT. In an additional experiment in the field enclosure it was found that ewes spent significantly more time near a lamb in a cage following both 5- and 20-micrograms doses of OT. In both experimental settings the high OT doses (10 and 20 micrograms) significantly increased the frequency of feeding although the effect was not dependent on oestrogen priming. These results demonstrate that central OT may play an important role in stimulating maternal behaviour in the sheep.
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PMID:Intracerebroventricular oxytocin stimulates maternal behaviour in the sheep. 361 55

Plasma samples were obtained before and during parturition from conscious rats implanted chronically with a jugular cannula. Rats were either allowed to remain in their nesting cage throughout parturition, or were moved immediately following the birth of the second or third pup into an empty glass chamber. The time-course of parturition was prolonged for mother rats which were moved in mid-parturition to this unfamiliar environment. However, in rats given an i.v. injection of the opioid antagonist naloxone at the time of transfer, parturition followed a normal time-course, and plasma oxytocin levels were significantly higher than in animals injected with saline. Thus our hypothesis is that stress activates opioid pathways which delay parturition by inhibiting oxytocin release. Opioid-mediated mechanisms may similarly be responsible for some problems in human parturition.
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PMID:Stress-induced disruption of parturition in the rat may be mediated by endogenous opioids. 365 12

Intracerebroventricular (ICV) infusion of the peptide hormone oxytocin has been previously reported to induce the performance of short-latency maternal behavior (less than one hour of exposure to foster pups required) in estrogen-treated, ovariectomized virgin rats. Tests for the effect of ICV oxytocin in maternal behavior latency have included transfer of animals from their home cage to a larger test cage one to two hours before oxytocin infusion. The importance of this test feature on peptide-induced short-latency maternal behavior was evaluated by varying the duration of the pre-test cage habituation. The responses of ovariectomized, estrogen-primed Zivic-Miller Sprague-Dawley rats housed in the test cages one week, two hours, or 0 hours before oxytocin or saline infusion were compared. It was found that only the rats given two hours of pre-test cage habituation responded to ICV oxytocin treatment with short-latency maternal behavior. This result is discussed with regard to the failure of other investigators to elicit short-latency maternal behavior with oxytocin. Possible neuroendocrine mechanisms for the interaction of degree of environment novelty with oxytocin-induced behavior are considered.
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PMID:Effect of varying the duration of pre-test cage habituation on oxytocin induction of short-latency maternal behavior. 373 11

Endogenous oxytocin released into the brain at parturition may stimulate the onset of maternal behaviour. In this study an attempt was made to block spontaneous maternal behaviour following natural delivery in Wistar rats by the injection of an antagonist of oxytocin into the cerebral ventricles. The analogue antagonist, d(CH2)5-8-ornithine-vasotocin, was administered by injection into a chronically implanted cannula in the right lateral ventricle at hourly intervals, beginning immediately after the expulsion of the first pup. The antagonist did not interfere with the normal progress of parturition or birth-related behaviours. After delivery of the last pup, mothers rested for 40 min in the test cage with the pups having been removed. Four pups and standard nesting material were then presented. Latency to pup carrying and duration of pup manipulation, nest building, and time spent on the nest with the pups, as well as duration of autogrooming and general activity were determined. Saline-injected controls started gathering the pups immediately and usually showed all elements of maternal behaviour within 10 min. Antagonist-treated mothers showed a marked delay in the onset of pup grouping and other maternal behaviours. At the end of 1 h, two out of six mothers had not yet picked up a single infant. Pups left overnight with their mothers were gathered into the nest and suckled, and no long-term effects of the antagonist were evident on retesting. The effectiveness of oxytocin antagonist in suppressing the rapid onset of post-partum maternal behaviour supports the hypothesis that centrally released oxytocin is involved in this process.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of post-partum maternal behaviour in the rat by injecting an oxytocin antagonist into the cerebral ventricles. 381 39

We have previously observed that about 60% of virgin, wild female house mice (Mus musculus), that were the offspring of wild mice trapped in Missouri, exhibited infanticide when a single 2-day-old pup was placed into each female's home cage. But, by the end of pregnancy, there was a significant increase (to 90%) in the proportion of wild female mice that exhibited infanticide. At parturition, infanticide was inhibited and parental behavior was induced in all females. In the present study we examined the influence of ovarian and adrenal hormones, as well as two hormones associated with pregnancy and parturition: oxytocin and prostaglandin F2 alpha (PGF), in regulating infanticide and parental behavior in wild female house mice. The presence or absence of gonadal and adrenal hormones did not influence the frequency of infanticidal behavior in adult female mice. Subcutaneous injections of either oxytocin or PGF inhibited infanticide in previously infanticidal pregnant females 1 hr after injection, but only oxytocin served to also facilitate parental behavior (most PGF-treated females left the pup untouched). Oxytocin, but not PGF, was effective in inhibiting infanticide in previously infanticidal virgin females. These findings suggest that, by themselves, ovarian and adrenal hormones do not mediate the exhibition of infanticide by wild female mice, but the lack of response to PGF in virgin females suggests that endocrine changes during pregnancy (possibly changes in steroids) may modulate the inhibitory effects of PGF on infanticide.
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PMID:Infanticide and parental behavior in wild female house mice: effects of ovariectomy, adrenalectomy and administration of oxytocin and prostaglandin F2 alpha. 395 78

PRL release, milk ejection, and electroencephalographic states of sleep were monitored in conscious, lactating Holtzman rats. Plasma PRL levels were low in rats separated from their litters, but they increased when pups were returned to the cage, attached to the nipples of the mother, and suckled. The pups emitted ultrasonic vocalizations upon their return to the cage and before their attachment to the nipples. Exposure of mothers to the vocalizations of pups, whereas nipple attachment was prevented, failed to increase PRL release. In confirmation of previous work, milk ejection did not occur until the suckled mother exhibited electroencephalographic signs of sleep, and milk ejection could be inhibited if sleep was prevented. In contrast, sleep was not a prerequisite for PRL release and sleep deprivation of suckled mothers could not inhibit release of PRL. In summary, suckling-induced release of PRL was followed by an increased incidence of sleep and then by milk ejection. It is hypothesized that the rise in plasma PRL induces the sleep necessary for the reflex release of oxytocin required for milk ejection.
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PMID:Relationship of prolactin release in lactating rats to milk ejection, sleep state, and ultrasonic vocalization by the pups. 669 Feb 94

Egg binding most often affects budgerigars, cockatiels, finches and canaries. Causes include oversized or malpositioned eggs, lack of exercise, nesting too early or late, excessive egg laying, uterine damage or infection, obesity, malnutrition, sudden drops in ambient temperature and genetic factors. Clinical signs are perching unsteadily with ruffled feathers and half-closed eyelids, frequent tail-wagging or straining, swelling over the tail base, and sitting on the cage bottom. Diagnosis is by physical examination and radiography. Treatment may involve increasing the ambient temperature to 85-90 F, lubricating the vent, IM injections of Ca solution and/or oxytocin, egg aspiration and laparotomy.
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PMID:Egg binding in caged and aviary birds. 673 18


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