Captopril and time dependent changes in post- to pre-glomerular resistance ratios in remnant kidneys of pre-hypertensive rats.
Micropuncture experiments were performed on intact and remnant kidneys of male Sprague-Dawley rats before and after angiotensin converting enzyme inhibition with captopril (0.5 mg kg-1 iv). Partially nephrectomized rats were studied at 2 and 8 weeks post-surgery before the development of systemic hypertension. At 2 weeks, nephrectomized rats had a numerically higher tubular stop-flow pressure than controls (43 +/- 2 mmHg vs. 38 +/- 2 mmHg; P = 0.08) and a higher post- to pre-glomerular resistance ratio (Re/Ra) (0.40 +/- 0.03 vs. 0.31 +/- 0.03; P = 0.08). At 8 weeks, stop-flow pressure and post- to pre-glomerular resistance ratios were similar in remnant and intact kidneys. Captopril had no effect on stop-flow pressure in 2 week post-surgery nephrectomized rats or either control group, but it increased stop-flow pressure in 8 week post-surgery nephrectomized rats (40 +/- 2 to 44 +/- 2 mmHg, P = 0.04). This increase in stop-flow pressure was associated with an increase in the post- to pre-glomerular resistance ratio (0.33 +/- 0.02-0.42 +/- 0.02, P = 0.009). Stop-flow pressure was positively correlated with the post- to pre-glomerular resistance ratio in 2-week post-surgery nephrectomized rats and their respective controls when combined (r = 0.89, P = 0.0001) and 8-week post-surgery nephrectomized rats and their respective controls combined (r = 0.78, P = 0.0001). Stop-flow pressure was not significantly correlated with mean arterial pressures or welling-point pressures in these groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Wilke
W L
WL
Department of Physiology, Colorado State University, Fort Collins 80523.
Persson
A E
AE
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002216:Captopril / Q000494:pharmacology; D006977:Hypertension, Renal / Q000209:etiology / Q000503:physiopathology*; D007678:Kidney Glomerulus / Q000098:blood supply* / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D009392:Nephrectomy; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology
D002216:Captopril