Role of intrarenal renin-angiotensin system on pressure-natriuresis in spontaneously hypertensive rats.
The pressure-natriuresis relationships in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were characterized with or without intrarenal renin-angiotensin system (RAS) blockade. The pressure-natriuresis relationship in SHR was shifted toward higher pressure in comparison to WKY. The inhibition of intrarenal RAS by MK-422 (0.3 ug/kg/min) in SHR enabled to excrete more sodium at the same pressure (P less than 0.05), whereas no significant changes were observed in WKY. In SHR, during administration of Thi5,8, D-Phe7-bradykinin (50 micrograms/kg/min), the natriuretic responses to MK-422 were maintained. Intrarenal infusion of Sar1, Ile8-angiotensin (70 ng/kg/min) into SHR increased sodium excretion accompanied by an increase in renal plasma flow. Intrarenally administered angiotensin I (10 ng/kg/min) into WKY showed antinatriuretic effects with minimal changes in renal hemodynamics. These results indicate that alteration of intrarenal RAS in SHR might contribute to reset the pressure-natriuresis relationship.
Takenaka
T
T
Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan.
Suzuki
H
H
Furukawa
T
T
Ogata
Y
Y
Saruta
T
T
D000809:Angiotensins / Q000494:pharmacology / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D015773:Enalaprilat / Q000494:pharmacology; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D009318:Natriuresis / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000502:physiology*
D000809:Angiotensins; D015773:Enalaprilat