Neumann, Inga D. and Torner, Luz and Toschi, Nicola and Veenema, Alexa H. (2006) Oxytocin actions within the supraoptic and paraventricular nuclei: differential effects on peripheral and intranuclear vasopressin release. AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 291 (1). R29-R36. ISSN 0363-6119,
Full text not available from this repository. (Request a copy)Abstract
In response to forced swimming (FS), AVP is released somato-dendritically within the supraoptic nucleus (SON) and paraventricular nucleus (PVN), but not from neurohypophyseal terminals into blood. Together with AVP, oxytocin (OXT) is released within the SON and PVN. Here, we studied the role of intra-SON and intra-PVN OXT in the regulation of local AVP release and into the blood in male rats. Within the SON, bilateral retrodialysis of an OXT receptor antagonist (OXT-A) increased local AVP release in response to FS [60 s, 21 degrees C, vehicle twofold, not significant (ns); OXT-A: 15-fold increase, P < 0.05] without significantly affecting basal AVP release. In addition, local OXT-A elevated plasma AVP secretion under basal conditions (twofold increase, P < 0.05) without further elevation after FS. Within the PVN, exposure to FS elevated local AVP release, reaching significance only in the OXT-A group (vehicle: 1.4-fold, ns; OXT-A: 1.6-fold increase, P = 0.050). Bilateral OXT-A into the PVN did not affect peripheral AVP secretion either under basal or stress conditions. Basal ACTH concentrations tended to be elevated by local OXT-A within the PVN (1.7-fold increase, P = 0.076). In contrast, the swim-induced ACTH secretion was attenuated after retrodialysis of OXT-A within both the SON (at 5 min) and PVN (at 15 min) (P < 0.05 both) compared with vehicle. The results demonstrate a receptor-mediated effect of OXT within the SON and PVN on local and neurohypophyseal AVP release, which depends upon the activity conditions. Further, while exerting an inhibitory effect on hypothalamo-pituitary-adrenal axis activity under basal conditions, hypothalamic OXT is essential for an adequate acute ACTH response.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PITUITARY-ADRENAL AXIS; HYPOTHALAMIC MAGNOCELLULAR NEURONS; FORCED SWIM TEST; BRAIN OXYTOCIN; STRESS RESPONSES; MEDIAN-EMINENCE; LACTATING RATS; HISTOAUTORADIOGRAPHIC DETECTION; CORTICOSTERONE RELEASE; SECRETORY ACTIVITY; plasma; hypothalamo-pituitary-adrenal axis; dendritic release; microdialysis; swim stress |
| Subjects: | 500 Science > 590 Zoological sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Zoologie > Tierphysiologie/Neurobiologie (Prof. Dr. Inga Neumann) |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 10 Feb 2021 07:42 |
| Last Modified: | 10 Feb 2021 07:42 |
| URI: | https://pred.uni-regensburg.de/id/eprint/34315 |
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