Vasopressin receptor subtypes on mesenteric and cremasteric arterioles in rat.
We studied the effects of a selective vasopressin V(1A) receptor antagonist [1-(1-(4-(3-acetylaminopropoxy)benzoyl)-4-piperidyl)-3, 4-dihydro-2(1H)-quinolinone (OPC-21268)] and a selective vasopressin V(2) receptor antagonist [5-dimethylamino-1(4-(2-methylbenzoylamino)benzoyl)-2,3,4, 5-tetrahydro-1H-benzazepine (OPC-31260)] on vasopressin-induced contraction of mesenteric and cremasteric arterioles in urethane-anaesthetized rats. Vasopressin was infused intravenously for 60 min or applied topically to arterioles directly. Vasopressin infusion (50, 100 or 500 ng/kg/min) decreased the diameter of both mesenteric and cremasteric arterioles. Vasopressin (500 ng/kg/min)-induced vasoconstriction was antagonized by OPC-21268 (0. 2, 1.0 and 5.0 mg/kg, i.v.), dose-dependently, but not by OPC-31260. Topically applied vasopressin (4.6x10(-10)-4.6x10(-8) M) dose-dependently constricted both microvessels. Pre-administration of OPC-21268 (5.0 mg/kg, i.v.) completely inhibited topically applied vasopressin-induced vasoconstriction in both microvessels, and OPC-31260 partially inhibited it in cremasteric arterioles. These results suggest that vasopressin induces vasoconstriction in rat mesenteric and cremasteric arterioles mainly by stimulating vasopressin V(1A) receptors, while vasoconstriction in cremasteric arterioles is partly associated with stimulation of vasopressin V(2) receptors.
Ishiguro
S
S
Department of Veterinary Pharmacology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, 890-0065, Kagoshima, Japan.
Iwasaki
T
T
Miyamoto
A
A
Mori
T
T
Nishio
A
A
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D001160:Arterioles / Q000187:drug effects* / Q000502:physiology; D001552:Benzazepines / Q000494:pharmacology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply*; D010880:Piperidines / Q000494:pharmacology; D015363:Quinolones / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017483:Receptors, Vasopressin / Q000145:classification* / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects
D001552:Benzazepines; D010880:Piperidines; D015363:Quinolones; D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin; C068644:OPC 21268; C076251:mozavaptan