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)

Colchicine blockade of axonal transport from the paraventricular nucleus to the median eminence was used to indirectly infer ACTH secretagog release in response to the psychological stressors of social interactions and various degrees of novelty. Placing a rat in a new cage with either the smell or presence of a novel conspecific decreased arginine vasopressin and oxytocin (OT) contents, but not corticotropin-releasing factor content. Secretagog contents were unchanged in rats in their home cages faced with a novel conspecific. Secretagog release during social stress is thus primarily a function of being in a novel setting. For different degrees of novelty, rats were placed in either a novel cage, a novel bucket, or a novel bucket smelling of another rat. Whereas secretagog contents were unchanged with a novel cage, OT content alone decreased in response to both the bucket and the unclean bucket. Despite a graded corticosterone response, there was no distinction in the OT response, suggesting that the colchicine technique cannot accurately reflect gradations of stressors.
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PMID:Patterns of adrenocorticotropin secretagog release in response to social interactions and various degrees of novelty. 789 37

Sexual interactions have multiple effects on oxytocin systems in the brain. In the present study we observed that allowing estrogen-progesterone treated ovariectomized rats to be mounted ten times by a male significantly decreased the density (beta max) of thymic oxytocin receptors. Animals were ovariectomized and after recovery injected once daily for three consecutive days with 0.5 microgram estradiol benzoate (EB) followed by an injection of 500 micrograms progesterone on the fourth day 4-5 hr before testing. They were either placed in a cage with a sexually-active male until mounted ten times (mounted) or were briefly placed in the cage and removed before being mounted (unmounted). Both groups were then killed and their thymuses aseptically removed. Computerized analysis of saturation binding data showed that the densities of oxytocin receptors from mounted animals were significantly (p < 0.02) lower than those of unmounted controls (beta max for unmounted animals = 8.45 +/- 0.84 fmol/mg protein; and for mounted rats = 5.5 +/- 0.33 fmol/mg protein; t6 = 3.23). The possibility is discussed that sexual activity reduces thymic oxytocin receptors which may alter immune responsiveness to sexually-transmitted diseases.
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PMID:Sexual activity decreases oxytocin receptor densities in the thymus. 838 70

After intracerebroventricular (icv) injection of arginine-vasopressin (AVP; 0.1, 1, 3, 10, 30 and 100 ng) or artificial cerebrospinal fluid (aCSF), heart rate (HR), core temperature (CT), and gross activity were monitored by a wireless telemetry system in rats in the home cage for a 60-min period. In addition, the simultaneous occurrence of various behaviors was recorded by an observer. Also, two structurally related peptides, oxytocin (OXT) and desglycinamide-arginine vasopressin (DGAVP), were tested (10 and 100 ng). Both the time-effect and dose-response relationships of AVP-induced changes in HR and CT were biphasic. Lower doses of AVP produced a tachycardia, whereas injection of higher doses of AVP caused a tachycardia preceded by a significant bradycardia. The concomitant mild rise in CT seen in rats treated with 1 and 3 ng AVP or with aCSF was attenuated in rats given 10 ng AVP; 30 ng AVP resulted in an immediate significant fall in CT, which was restored to control values at 30 min after administration. An inverted U-shaped dose-response relationship was observed for gross activity, locomotion, and rearing behavior, whereas grooming behavior was most marked after the highest dose of AVP. OXT induced a grooming response and cardiac acceleration at the 100-ng dose only, whereas DGAVP produced no effect. To investigate the role of endogenous AVP in the maintenance of tonic ANS activity under resting conditions, rats were treated intracerebroventricularly (icv) with the V1 antagonist d(CH2)5-[Tyr(Me)2]AVP or polyclonal antiserum (W1E) against AVP. During the first 10 min after icv injection of 3 and 10 ng of the antagonist, an increase in HR, CT, and behavioral activation was observed, effects opposite to those produced by the higher dose of AVP. The same variables remained unchanged after administration of 100 ng of the antagonist. W1E injected icv was without effect. In summary, central effects of AVP on autonomic and behavioral activity seem to be mediated by differential neural pathways. In addition, a structure-activity relation seems to exist for the AVP-induced effects. Finally, these results suggest that AVP plays but a minor role in the maintenance of tonic activity of the ANS.
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PMID:Differential effects of centrally injected AVP on heart rate, core temperature, and behavior in rats. 843 Aug 86

The vocal response rates of 12-13-day-old infant rats to isolation in a bare test box are markedly increased by brief (1-min) periods of contact with an anesthetized dam prior to isolation, without affecting other isolation-induced behaviors. No such potentiation followed brief contact with littermates, novel test conditions, or experimenter handling. Brief contact with the dam was equally effective in the test chamber or home cage and was not further enhanced by repeated contact-separation sequences. Passive contact became ineffective when prolonged to 30 min, and potentiation could not be restored by providing the additional reinforcing events of continuous suckling, periodic oxytocin-induced milk letdown, or bouts of simulated maternal licking. However, when pups engaged in active interaction with an awake dam, potentiation was significantly enhanced following 1-, 10-, and 30-min periods. A working hypothesis is outlined for the adaptive role of potentiation in the development of the rat pup.
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PMID:Maternal interactions prior to separation potentiate isolation-induced calling in rat pups. 891 18

The effects of emotional stressors on the release of arginine vasopressin (AVP) and oxytocin (OXT) within the rat hypothalamus and the origin and physiological significance of AVP released within the hypothalamic paraventricular nucleus (PVN) were investigated. First, adult male Wistar rats with a microdialysis probe aimed at the PVN or the supraoptic nucleus were exposed to either a dominant male rat (social defeat) or a novel cage. Release of AVP within the PVN was significantly increased in response to social defeat but not to novelty. In contrast to an activation of the hypothalamic-pituitary-adrenal (HPA) system, neither stressor stimulated the hypothalamic-neurohypophysial system (unchanged plasma AVP and OXT and unchanged release within the supraoptic nucleus [AVP] and the PVN [OXT]). Next, we demonstrated by simultaneous microdialysis of the suprachiasmatic nucleus and the PVN that AVP measured in PVN dialysates during social defeat was probably of intranuclear origin. Finally, a mixture of a V1 AVP and the alpha-helical corticotropin-releasing hormone (CRH) receptor antagonists administered via inverse microdialysis into the PVN caused a significant increase in the plasma adrenocorticotropic hormone (ACTH) concentration compared with vehicle-treated controls both under basal conditions and during social defeat, indicating inhibitory effects of intra-PVN-released AVP and/or CRH on HPA system activity. The antagonists failed to affect anxiety-related behavior of the animals as assessed with the elevated plus-maze. Taken together, our results show for the first time that AVP is released within the PVN in response to an emotional stressor. We hypothesize that this intranuclear release provides a negative tonus on ACTH secretion.
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PMID:Release of vasopressin within the rat paraventricular nucleus in response to emotional stress: a novel mechanism of regulating adrenocorticotropic hormone secretion? 892 28

The present study evaluated the behavioral repertoire of lactating CD-1 mouse dams when tested in an environment associated with cocaine in the premating period. Virgin females were randomly assigned for conditioning (8-day long schedule with four cocaine or saline injections administered every other day) to three experimental groups: i) Coc-Test females received one injection of cocaine (5 or 20 mg/kg IP) in the testing chamber and saline 24 h later in the home cage, ii) Coc-Home females received one injection of the same doses of cocaine in the home cage and saline 24 h later in the testing chamber, and iii) Sal-Sal control females received one saline injection in both environments. All females underwent a 25-day long wash out period during which they were mated. Their behavior was subsequently scored in the testing chamber on postpartum day 2 (drug-free state) in the presence of 3 pups from their own litter (single 15-min session). As a whole, Coc-Test dams appeared to be more involved in pup-directed activities such as pup-nosing and nest-building when compared with the Coc-Home group. In addition, non-pup directed behaviors, such as crossing, self-grooming, and rearing were higher in Coc-Test group than in other groups. The opposite was true for stereotyped gnawing activity. A measure of females' body weight gain revealed that Coc-Test 20 group was significantly higher than other groups particularly during the postpartum phase. On postpartum day 6, lactating dams were injected with the low cocaine dose (5mg/kg) and their response to a male intruder was assessed in the testing chamber (single 5-min session). A higher number of Coc-Test 5 dams showed the on nest and the upright offensive postures compared to the corresponding Coc-Home 5 group, whereas a significant higher number of Sal-Sal females showed the on top posture with respect to the Coc-Test 20 group. Oxytocin levels measured after the behavioral test showed a tendency, even if not significant, to be higher in the hypothalamus of Coc-Test dams. As a whole, the present results suggest that the alterations in maternal behavior here observed as well as the trend underlined by oxytocin values, cannot be ascribed to carry-over effects of cocaine administration in the pre-mating phase per se; rather, they seem to represent a conditioned response to the distinct environment previously associated with the drug experience.
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PMID:Prior cocaine exposure in different environments affects the behavioral responses of mouse dams. 907 94

The present study examines plasma oxytocin levels in relation to performance of copulatory behavior in male rats. The animals were divided into three groups: A) home-cage controls, B) sexually naive and C) sexually experienced. Following 15 min of sexual interactions with a sexually proceptive female, brought into estrus by sequential injections of estradiol benzoate (12.5 micrograms animal-1, -48 h) and progesterone (0.5 mg animal-1, -6 h), the male rats were decapitated. Trunk blood was collected for preparation of plasma samples, and subsequent radioimmunoassay for oxytocin. Home-cage controls, not exposed to a sexually proceptive female, were decapitated at the same time as experimental animals. It was found that plasma oxytocin levels were significantly elevated in sexually naive rats following exposure to a sexually proceptive female, and that plasma oxytocin levels were highly correlated with intensity of copulatory performance in these animals. In addition, it was also found that plasma prolactin and glucose levels were increased, regardless of sexual experience, in comparison with home-cage controls. It is concluded that the emotional challenge, and the situation-specific demands for action, created by an encounter with a sexually proceptive female, are accompanied by an increased plasma concentration of oxytocin in sexually naive, but not sexually experienced, male rats.
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PMID:Sexual motivation promotes oxytocin secretion in male rats. 943 35

In order to study neuroendocrine and behavioural stress responses in female rats post partum we aimed to establish a relevant emotional stressor -- the maternal defence test based on maternal aggression of a lactating resident towards a virgin or lactating intruder approaching the cage. Exposure to maternal defence significantly elevated corticotropin (ACTH) and corticosterone responses of the residents and of virgin or lactating intruders, with an attenuated response in lactating residents and lactating intruders. Exposure to maternal defence increased plasma oxytocin in virgin intruders only. The aggressive behaviour displayed by the residents was directly correlated with the amount of defensive behaviour of the intruder and independent of the intruder's reproductive state. However, the amount of maternal and explorative behaviours displayed by the lactating residents was significantly higher when exposed to a lactating, compared to a virgin, intruder. ACTH responses in lactating residents exposed to virgin intruders were significantly correlated to the amount of offensive (direct correlation) and maternal (inverse correlation) behaviours they displayed. Plasma prolactin concentrations, elevated in lactating compared to virgin rats under basal conditions, were found to be reduced in the lactating residents and intruders in response to exposure to the maternal defence test, whereas it was unchanged in virgin intruders. To test for the involvement of brain oxytocin in neuroendocrine and behavioural responses of the lactating residents an oxytocin receptor antagonist (0.1 microg/5 microL) was infused icv 10 min prior to testing. This treatment increased basal, but not stress-induced, ACTH, corticosterone and oxytocin secretion. Whereas parameters of aggressive behaviour were unchanged, the antagonist reduced signs of maternal behaviour during maternal defence. In summary, the maternal defence test has been characterized as a relevant emotional stressor for female rats which is useful for studying neuroendocrine and emotional responses in females, in particular in the context of reproductive adaptations.
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PMID:Maternal defence as an emotional stressor in female rats: correlation of neuroendocrine and behavioural parameters and involvement of brain oxytocin. 1126 75

We previously found stress-reduction in rats exposed to an oxytocin-injected cage-mate. Olfactory impairment and oxytocin antagonist treatment blocked the effect. Here, we investigated effects of social stress on the exposure-induced response and exposure on amygdaloid oxytocin concentrations. CT concentrations in exposed olfactorily impaired, CT antagonist-treated and saline-injected unexposed rats were reduced, compared to the significantly higher level in untreated and exposed saline-injected rats. Saline injections and group mixing enhanced heat dissipation. Exposure abolished the injection-induced, but not mixing-induced stress response, most likely via a social stress induced effect on the oxytocin-injected rat. The difference in exposure responsivity may relate to recognition, stress type and intensity affecting different stress-response systems. The mechanism could reinforce social attachment.
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PMID:Social stress blocks energy conservation in rats exposed to an oxytocin-injected cage mate. 1216 65

In previous studies we found indications of stress reduction in saline-injected rats when exposed to an oxytocin (OT)-injected cage mate. Olfactory impairment and OT antagonist treatment abolished the effects. This suggested an olfactorily mediated oxytocinergic stress-inhibitory mechanism. To test this hypothesis bodyweight, tail skin temperatures, food-intake and plasma ACTH and corticosterone concentrations were analysed. Suppressed weight loss and decreased stress-hormone release was found in saline-injected rats exposed to an OT-injected cage mate, but not in OT antagonist-injected rats, supporting the hypothesis. Our results suggest that OT in a stressed animal can inhibit the olfactory stress cues emitted, and that the olfactory cues from the stressed animal can influence an OT in pathway in the odour recipient animals to reduce stress effects.
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PMID:Energy conservation in stressed rats exposed to an oxytocin-injected cage mate. 1216 72


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