title: Effects of V2 receptor activity on the pressor response to vasopressin in the rat.
abstract: 1. To determine the contribution of V1 and V2 receptor activity on the enhancement of reflex buffering of the pressor response to arginine-vasopressin (AVP), mean arterial pressure (MAP) and heart rate (HR) changes were examined in response to graded injections of phenylephrine, AVP, or Phe2Orn8OT, a potent, selective V1-receptor agonist in the absence and presence of Val4DArg8VP, a potent, selective V2-receptor agonist. 2. There were no significant differences in MAP responses to the V1 agonist in the absence and presence of the V2 agonist in either conscious intact or autonomic-blocked rats. 3. Autonomic blockade with methscopolamine and hexamethonium increased the pressor sensitivity to phenylephrine threefold. In contrast, the pressor sensitivities to AVP and Phe2Orn8OT were increased 14-fold and 11-fold, respectively, by autonomic blockade. 4. V2-receptor activity does not have any inherent vasocative action or synergistic vasoactive action with V1-receptor activity. 5. V2 receptors do not play a role in enhancing reflex buffering of the pressor response to AVP; V1 receptors are suggested to play the role.
authors.affiliation: Monash University Department of Medicine, Melbourne, Victoria, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Shimizu
authors.forename: J
authors.initials: J
authors.lastname: Schwartz
authors.forename: B P
authors.initials: BP
authors.lastname: McGrath
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001340:Autonomic Nerve Block; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D003894:Deamino Arginine Vasopressin / Q000031:analogs & derivatives / Q000494:pharmacology; D008297:Male; D010121:Oxytocin / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000502:physiology*; D017483:Receptors, Vasopressin; D012018:Reflex / Q000187:drug effects / Q000502:physiology
chemical_list: D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin; C047063:oxytocin, Phe(2)-Orn(8)-; D010121:Oxytocin; C007223:vasopressin, 1-deamino-4-Val-8-Arg-; D003894:Deamino Arginine Vasopressin