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°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 (two-fold 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. Copyright © 2006 the American Physiological Society.

Neumann, I., Torner, L., Toschi, N., Veenema, A. (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 [10.1152/ajpregu.00763.2005].

Oxytocin actions within the supraoptic and paraventricular nuclei: Differential effects on peripheral and intranuclear vasopressin release

TOSCHI, NICOLA;
2006-01-01

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°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 (two-fold 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. Copyright © 2006 the American Physiological Society.
2006
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore FIS/07 - FISICA APPLICATA (A BENI CULTURALI, AMBIENTALI, BIOLOGIA E MEDICINA)
Settore MED/13 - ENDOCRINOLOGIA
Settore MED/25 - PSICHIATRIA
English
Con Impact Factor ISI
hormone antagonist; oxytocin receptor antagonist; unclassified drug; vasopressin, animal experiment; animal tissue; article; controlled study; drug effect; hormonal regulation; hormone action; hormone blood level; hormone release; male; nonhuman; priority journal; rat; supraoptic nucleus; thalamus midline nucleus, Adrenocorticotropic Hormone; Animals; Arginine Vasopressin; Hypothalamo-Hypophyseal System; Male; Oxytocics; Oxytocin; Paraventricular Hypothalamic Nucleus; Pituitary-Adrenal System; Rats; Rats, Inbred WF; Supraoptic Nucleus
Neumann, I., Torner, L., Toschi, N., Veenema, A. (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 [10.1152/ajpregu.00763.2005].
Neumann, I; Torner, L; Toschi, N; Veenema, A
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/29076
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