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Abstract
Intracerebroventricular administration of oxytocin reduces anxiety behavior and hypothalamo-pituitary-adrenal (HPA) responses to stress in female rats. Similar changes are seen in late-pregnant rats, and oxytocin-sensitive pathways may mediate these effects. This study investigated anxiety behavior and stress responses using a gonadal steroid model of late pregnancy, which is known to increase endogenous oxytocin expression. Compared with continuous progesterone treatment, 3-d withdrawal of progesterone after 11-d treatment of ovariectomized rats with estradiol and progesterone resulted in increased binding of the oxytocin receptor ligand [125I]d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH29]ornithine vasotocin in selective forebrain regions, including the ventrolateral septum and ventromedial hypothalamus. Behavior in the elevated plus-maze indicated that progesterone withdrawal had an anxiolytic effect, and this was associated with lower levels of c-fos mRNA expression in the ventral hippocampus, an area previously shown to be sensitive to oxytocin. In other groups of animals, the plasma corticosterone response to a psychological stress (10 min of 114 dB white noise) was significantly attenuated by this steroid manipulation. Furthermore, simultaneous infusion of the selective oxytocin receptor antagonist desGlyNH2, d(CH2)5[Tyr(Me)2,Thr4]OVT during the period of progesterone withdrawal reversed this attenuation of noise-induced HPA activation, indicating a role for endogenous oxytocin in this effect. Thus, mimicking the steroid profile of late pregnancy leads to a reduction in anxiety behavior and attenuates HPA activity induced by mild stress. These effects appear to be mediated through the involvement of central oxytocin neurotransmission.
Translated title of the contribution | Gonadal steroid modulation of stress-induced hypothalamo-pituitary-adrenal activity and anxiety behavior: role of central oxytocin |
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Original language | English |
Pages (from-to) | 2423 - 2431 |
Number of pages | 9 |
Journal | Endocrinology |
Volume | 147 (5) |
DOIs | |
Publication status | Published - May 2006 |
Bibliographical note
Publisher: Endocrine SocietyFingerprint
Dive into the research topics of 'Gonadal steroid modulation of stress-induced hypothalamo-pituitary-adrenal activity and anxiety behavior: role of central oxytocin'. Together they form a unique fingerprint.Projects
- 1 Finished
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THE IMPORTANCE OF PULSATILE SECRETION FOR GLUCOCORTICOID SIGNALLING
Lightman, S. L. (Principal Investigator)
1/07/05 → 1/07/08
Project: Research