PT  - JOURNAL ARTICLE
AU  - D P Brooks
AU  - R M Edwards
AU  - P D Depalma
AU  - T A Fredrickson
AU  - J P Hieble
AU  - M Gellai
TI  - The water diuretic effect of the alpha-2 adrenoceptor agonist, AGN 190851, is species-dependent.
DP  - 1991 Dec 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 1277--1282
VI  - 259
IP  - 3
4099  - http://jpet.aspetjournals.org/content/259/3/1277.short
4100  - http://jpet.aspetjournals.org/content/259/3/1277.full
SO  - J Pharmacol Exp Ther1991 Dec 01; 259
AB  - The effect of the novel alpha-2 adrenoceptor agonist, AGN 190851, was evaluated for its diuretic action in the rat, dog and cynomolgus monkey and its ability to inhibit vasopressin-stimulated cyclic AMP accumulation in rat and dog cortical collecting tubules in vitro. The data indicate that in the rat, AGN 190851 resulted in a dose-dependent water diuresis, which was accompanied by an increase in blood pressure and osmolar clearance. In addition, AGN 190851 resulted in a dose-dependent inhibition of vasopressin-stimulated cyclic AMP accumulation in rat cortical collecting tubules in vitro. In contrast, AGN 190851 was unable to cause either a water diuresis in conscious dogs or inhibit vasopressin-stimulated adenylate cyclase activity in canine tissue in vitro. In the lightly anesthetized cynomolgus monkey, AGN 190851 also failed to alter renal function significantly. Administration of the vasopressin receptor antagonist, SK&F 105494, to either dogs or cynomolgus monkeys demonstrated that antagonism of the vasopressin V2 receptor could result in a brisk water diuresis in both species. The data demonstrate that alpha-2 adrenoceptors can functionally antagonize vasopressin antidiuretic activity in the rat, but not in the dog or cynomolgus monkey.