Effect of Intracerebroventricular Captopril on Vasopressin and Blood Pressure in Spontaneously Hypertensive Rats

• Published in: Hypertension (Dallas, Tex. 1979) Tex. 1979), 1981-11, Vol.3 (6 Suppl II), p.II-71-II-74
• Main Authors: CROFTON, JOAN T, ROCKHOLD, ROBIN W, SHARE, LEONARD, WANG, BIN C, HOROVITZ, ZOLA P, MANNING, MAURICE, SAWYER, WILBUR H
• Format: Article
• Language: English
• Subjects: Animals; Blood Pressure - drug effects; Captopril - administration & dosage; Captopril - therapeutic use; Hypertension - drug therapy; Injections, Intraventricular; Male; Proline - analogs & derivatives; Rats; Rats, Inbred Strains; Vasopressins - antagonists & inhibitors; Vasopressins - blood; Vasopressins - metabolism
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/01.hyp.3.6_pt_2.ii-71

SUMMARY In conscious, unrestrained spontaneously hypertensiTe rats (SHR), mean arterial blood pressure (MAP) increased from a pretreatment value of 150±4 to 179±7 mm Hg within 10 min (p < 0.01) following an intracerebroventricular (I.C.T.) Injection of captopril (2 mg/kg body weight), and the plasma vasopressin concentration was increased eightfold (p < 0.01). MAP then fell to 131±5 mm Hg at 120 minutes (p < 0.01), and plasma vasopressin concentration returned to pretreatment levels. The initial increase in MAP was due in large part to increased plasma vasopressin levels since this increase was reduced 50% by pretreatment with a specific antagonist of the pressor action of vasopressin. The reduction in MAP at 120 minutes in captopril-treated rats may have been nonspecific, rince a similar effect was observed in SHR given an l.c.v. injection of a control solution. In (Wistar-Kyoto) WKY rats, i.cv. captopril was without a statistically significant effect on MAP, but the plasma vasopressin concentration increased three-fold (p < 0.01). These findings may reflect an increased sensitivity of the control system for vasopressin release in the SHR. (Hypertension 3 (suppl II)II-71-II-74, 1981)