Effects of a calcium antagonist and an angiotensin II receptor antagonist on rat renal arterioles.
The objective of this study was to investigate the effects of a dihydropyridine calcium antagonist, manidipine HCl, and an angiotensin II receptor antagonist, CV-11974, on renal microvasculature in hypertensive rats. Hydronephrosis was induced by ligation of the left ureter in 8-week-old stroke-prone spontaneously hypertensive rats. Two months after the operation, the hydronephrotic kidney was split longitudinally and spread out as a thin sheet, and the renal microvasculature was observed directly under a light microscope. Administration of manidipine HCl (20 micrograms/kg) caused a gradual fall in blood pressure (-34 mmHg). The afferent arterioles were dilated, and maintained the same level of dilatation until 30 min (+20%). The efferent arterioles were also dilated (+8%). Glomerular blood flow was significantly increased (+38%). Administration of CV-11974 (100 micrograms/kg) caused a sharp fall in blood pressure at 2 min (-24 mmHg), with a continuous fall in blood pressure until 60 min (-46 mmHg). The afferent arterioles were gradually dilated (+15%). The efferent arteriole was also dilated until 60 min, but to a lesser extent than the afferent arteriole. Glomerular blood flow was immediately increased (+35%). We conclude that both manidipine HCl and CV-11974 dilated both the afferent and efferent arterioles and increased glomerular blood flow.
Kimura
K
K
Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Tojo
A
A
Hirata
Y
Y
Hayakawa
H
H
Goto
A
A
Omata
M
M
D057911:Angiotensin Receptor Antagonists; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001160:Arterioles / Q000187:drug effects; D001562:Benzimidazoles / Q000494:pharmacology; D001713:Biphenyl Compounds; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004095:Dihydropyridines / Q000494:pharmacology*; D005260:Female; D006869:Hydronephrosis / Q000503:physiopathology; D006973:Hypertension / Q000503:physiopathology; D007668:Kidney / Q000098:blood supply*; D009578:Nitrobenzenes; D010879:Piperazines; D051381:Rats; D011918:Rats, Inbred SHR; D012077:Renal Artery; D013777:Tetrazoles / Q000494:pharmacology
D057911:Angiotensin Receptor Antagonists; D000959:Antihypertensive Agents; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D009578:Nitrobenzenes; D010879:Piperazines; D013777:Tetrazoles; C054218:manidipine; C081643:candesartan