Chronic and selective vasopressin blockade in spontaneously hypertensive rats
Okada, H.; Suzuki, H.; Kanno, Y.; Yamamura, Y.; Saruta, T.
American Journal of Physiology 267(6 Pt 2): R1467-R1471
1994
ISSN/ISBN: 0002-9513 PMID: 7810754 Document Number: 426407
Chronic effects of orally available, nonpeptide vasopressin V-1 and V-2 receptor antagonists on conscious spontaneously hypertensive rats (SHR) were investigated. SHR and Wistar rats were divided into four groups, groups S-1 to S-4 and W-1 to W-4, respectively. Groups S- 1 and W- 1 were untreated as control. Groups S-2 and W-2 were treated with V-1 antagonist, groups S-3 and W-3 received V2 antagonist, and groups S-4 and W-4 were treated with both of V-1 and V-2 antagonists. V-1 and/or V-2 antagonists did not affect degree of blood pressure of W-2, W-3, and W-4 rats, and V-1 antagonist, alone or combined with V-2 antagonist, slightly reduced increases in blood pressure of S-2 and S-4 rats without significance. However, V-2 antagonist induced significantly massive and hyposmolar urine in W-3 rats compared with that in S-3 rats. ln conclusion, in SHR, circulating vasopressin contributes to increases in blood pressure via either V-1 or V-2 receptors less than expected from previous studies with antibodies or peptide antagonists.