Vasopressin pressor receptor-mediated activation of HPA axis by acute ethanol stress in rats.
The plasma arginine vasopressin (AVP), ACTH, and corticosterone levels and the hypothalamic corticotropin-releasing hormone (CRH) content were measured after oral administration of 1 ml of 75% ethanol to rats, a model known to induce acute gastric erosions and stress. Elevated plasma AVP, ACTH, and corticosterone levels were detected 1 h after ethanol administration. Treatment with the vasopressin pressor (V(1)) receptor antagonist [d(CH(2))(5)Tyr(Me)-AVP] before ethanol administration significantly reduced the ACTH and corticosterone level increases. A higher hypothalamic CRH content was measured at 30 or 60 min after ethanol administration. V(1) receptor antagonist injection, 5 min before ethanol administration, inhibited the rise in hypothalamic CRH content. The protein synthesis blocker cycloheximide prevented the hypothalamic CRH content elevation after stress. The AVP-, CRH-, and AVP + CRH-induced in vitro ACTH release in normal anterior pituitary tissue cultures was also prevented by pretreatment with the V(1) receptor antagonist. The results support the hypothesis that stress-induced AVP may not only act directly on the ACTH producing anterior pituitary cells but also indirectly at the hypothalamic level via the synthesis and release of CRH.
László
F A
FA
Department of Comparative Physiology, Attila József University of Sciences, H-6726 Szeged, Hungary. laszlof@koki.hu
Varga
C
C
Pávó
I
I
Gardi
J
J
Vecsernyés
M
M
Gálfi
M
M
Morschl
E
E
László
F
F
Makara
G B
GB
D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000378:metabolism*; D000435:Alcoholic Intoxication / Q000097:blood / Q000503:physiopathology*; D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D003345:Corticosterone / Q000097:blood / Q000378:metabolism*; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology / Q000502:physiology*; D003513:Cycloheximide / Q000494:pharmacology; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology* / Q000503:physiopathology; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D017483:Receptors, Vasopressin / Q000187:drug effects / Q000502:physiology*
D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D003513:Cycloheximide; D003345:Corticosterone