Vasopressin V(1) receptor-mediated activation of central sympatho-adrenomedullary outflow in rats.
The present study was designed to characterize the vasopressin receptor subtype involved in the vasopressin-induced activation of the central sympatho-adrenomedullary outflow using urethane-anesthetized rats. Intracerebroventricularly (i.c.v.) administered vasopressin (0.1, 0.2 and 0.5 nmol/animal) dose-dependently elevated plasma levels of adrenaline and noradrenaline (adrenaline>noradrenaline). The vasopressin (0.2 nmol/animal)-induced elevation of both catecholamines was significantly attenuated by [d(CH(2))(5)(1),Tyr(Me)(2),Arg(8)]-vasopressin, a selective vasopressin V(1) receptor antagonist, in a dose-dependent manner (0.1 and 0.2 nmol/animal, i.c.v.). The same doses (0.1 and 0.2 nmol/animal, i.c.v.) of [1-adamantaneacetyl(1),D-Tyr(Et)(2),Val(4),Abu(6), Arg(8,9)]-vasopressin, a potent vasopressin V(2) receptor antagonist, had no effect; however, a large dose of this antagonist (1.6 nmol/animal, i.c.v.) effectively reduced the vasopressin-induced elevation of catecholamines. On the other hand, [5-dimethylamino-1-[4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrahydro-1H-benzazepine], a selective vasopressin V(2) receptor antagonist (5 and 10 nmol/animal, i.c.v.), had no effect on the vasopressin-induced elevation of catecholamines. The vasopressin-induced elevation of catecholamines was abolished by indomethacin, an inhibitor of cyclooxygenase (1.2 micromol/animal, i.c.v.). These results suggest that the vasopressin activates the central sympatho-adrenomedullary outflow by brain vasopressin V(1) receptor- and cyclooxygenase-dependent mechanisms in rats.
Okada
Shoshiro
S
Department of Pharmacology, Kochi Medical School, Nankoku, Kochi 783-8505, Japan.
Murakami
Yoshinori
Y
Nakamura
Kumiko
K
Yokotani
Kunihiko
K
D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000097:blood*; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar; D017483:Receptors, Vasopressin / Q000502:physiology*; D013997:Time Factors; D014667:Vasopressins / Q000494:pharmacology
D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines; D016861:Cyclooxygenase Inhibitors; D017483:Receptors, Vasopressin; D014667:Vasopressins; D001127:Arginine Vasopressin; C076251:mozavaptan; D009638:Norepinephrine; D007213:Indomethacin; D004837:Epinephrine