In response to various stressors, oxytocin is released not only into blood, but also within hypothalamic and extrahypothalamic limbic brain regions. Here, we describe the involvement of intracerebrally released oxytocin in the regulation of the activity of the hypothalamo-pituitary-adrenal (HPA) axis by infusion of the oxytocin receptor antagonist (des Gly-NH2 d(CH2)5 [Tyr(Me)2, Thr4] OVT; pH 7.4; Dr. M. Manning, Toledo, OH, USA) either into the lateral cerebral ventricle (icv[0.75 μg/5 μl,]) or via retrodialysis (10 μg/ml, 3.3 μl/min, 15 min) into the hypothalamic paraventricular nuclei (PVN), the medio-lateral septum or the amygdala. Male Wistar rats fitted with a chronic jugular vein catheter and an icv guide cannula or a microdialysis probe targeting the respective brain region 4 days prior to the experiment were blood sampled under basal as well as stressful conditions. Rats were exposed to the elevated platform (emotional stressor) and/or to forced swimming (combined physical and emotional stressor). Blockade of the receptor-mediated action of endogenous oxytocin within the PVN resulted in an enhanced basal secretion of ACTH whereas, in response to forced swimming, ACTH secretion was rather reduced, indicating a tonic inhibitory effect of OXT on basal HPA axis activity, but a potentiating action under conditions of stress. Within the medio-lateral septum, antagonist treatment did not alter basal ACTH secretion, but significantly disinhibited ACTH secretion in response to the elevated platform, but not to forced swimming. Within the amygdala, no significant effects either on basal or stress-induced HPA axis activity could be found. The results indicate a differential involvement of brain oxytocin in the regulation of the HPA axis activity which depends both on the site of intracerebral oxytocin release and the stressor the animals are exposed to. Copyright (C) 2000 Elsevier Science B.V.

Neumann, I., Krömer, S., Toschi, N., Ebner, K. (2000). Brain oxytocin inhibits the (re)activity of the hypothalamo-pituitary-adrenal axis in male rats: Involvement of hypothalamic and limbic brain regions. REGULATORY PEPTIDES, 96(1-2), 31-38 [10.1016/S0167-0115(00)00197-X].

Brain oxytocin inhibits the (re)activity of the hypothalamo-pituitary-adrenal axis in male rats: Involvement of hypothalamic and limbic brain regions

TOSCHI, NICOLA;
2000-01-01

Abstract

In response to various stressors, oxytocin is released not only into blood, but also within hypothalamic and extrahypothalamic limbic brain regions. Here, we describe the involvement of intracerebrally released oxytocin in the regulation of the activity of the hypothalamo-pituitary-adrenal (HPA) axis by infusion of the oxytocin receptor antagonist (des Gly-NH2 d(CH2)5 [Tyr(Me)2, Thr4] OVT; pH 7.4; Dr. M. Manning, Toledo, OH, USA) either into the lateral cerebral ventricle (icv[0.75 μg/5 μl,]) or via retrodialysis (10 μg/ml, 3.3 μl/min, 15 min) into the hypothalamic paraventricular nuclei (PVN), the medio-lateral septum or the amygdala. Male Wistar rats fitted with a chronic jugular vein catheter and an icv guide cannula or a microdialysis probe targeting the respective brain region 4 days prior to the experiment were blood sampled under basal as well as stressful conditions. Rats were exposed to the elevated platform (emotional stressor) and/or to forced swimming (combined physical and emotional stressor). Blockade of the receptor-mediated action of endogenous oxytocin within the PVN resulted in an enhanced basal secretion of ACTH whereas, in response to forced swimming, ACTH secretion was rather reduced, indicating a tonic inhibitory effect of OXT on basal HPA axis activity, but a potentiating action under conditions of stress. Within the medio-lateral septum, antagonist treatment did not alter basal ACTH secretion, but significantly disinhibited ACTH secretion in response to the elevated platform, but not to forced swimming. Within the amygdala, no significant effects either on basal or stress-induced HPA axis activity could be found. The results indicate a differential involvement of brain oxytocin in the regulation of the HPA axis activity which depends both on the site of intracerebral oxytocin release and the stressor the animals are exposed to. Copyright (C) 2000 Elsevier Science B.V.
2000
Pubblicato
Rilevanza internazionale
Abstract
Sì, ma tipo non specificato
Settore FIS/07 - FISICA APPLICATA (A BENI CULTURALI, AMBIENTALI, BIOLOGIA E MEDICINA)
Settore MED/13 - ENDOCRINOLOGIA
English
Con Impact Factor ISI
corticotropin; oxytocin; oxytocin antagonist; oxytocin receptor, amygdaloid nucleus; animal experiment; anterior hypothalamus; conference paper; controlled study; corticotropin blood level; corticotropin release; electrophysiology; hypothalamus hypophysis adrenal system; limbic system; male; mental stress; microdialysis; nonhuman; priority journal; rat; swimming, Adrenocorticotropic Hormone; Animals; Brain Chemistry; Hormone Antagonists; Hypothalamo-Hypophyseal System; Male; Ornipressin; Oxytocin; Pituitary-Adrenal System; Rats; Rats, Wistar; Receptors, Oxytocin; Stress; Swimming, Animalia; Rattus norvegicus
Neumann, I., Krömer, S., Toschi, N., Ebner, K. (2000). Brain oxytocin inhibits the (re)activity of the hypothalamo-pituitary-adrenal axis in male rats: Involvement of hypothalamic and limbic brain regions. REGULATORY PEPTIDES, 96(1-2), 31-38 [10.1016/S0167-0115(00)00197-X].
Neumann, I; Krömer, S; Toschi, N; Ebner, K
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/51852
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