Glomerular response to verapamil by isolated spontaneously hypertensive rat kidney

Publisher Website
Google Scholar
Abstract
Altered cell Ca regulation may affect function of isolated Kyoto spontaneously hypertensive rat (SHR) kidneys as compared with kidneys from Wistar-Kyoto control (WKY) rats. The kidneys were perfused at 120 and 160 mm Hg. At 120 mm Hg, SHR glomerular filtration rate (GFR) was 0.24 .+-. 0.04 compared with WKY GFR of 0.70 .+-. 0.10 ml/min (P = 0.001). At 160 mm Hg, SHR GFR was 0.48 .+-. 0.05 compared with WKY GFR of 1.09 .+-. 0.05 ml/min (P < 0.001). At 120 mm Hg, addition of norepinephrine increased renal vascular resistance (RVR) by 50% and decreased SHR GFR by 27% and WKY GFR by 57% (P = 0.04). At 160 mm Hg, norepinephrine elicited similar changes. Addition of verapamil, 5-10 .mu.M, in the presence of norepinephrine returned RVR to 100-100% of control. With verapamil at 120 mm Hg, SHR GFR increased to 0.84 .+-. 0.23 ml/min a value 3.5 times that of control (P = 0.03). WKY GFR in the presence of norepinephrine and verapamil was 0.97 .+-. 0.07 ml/min, unchanged from control (R = 0.07). At 160 mm Hg, norepinephrine and verapamil also failed to increase WKY GFR above control (P = 0.4) but increased SHR GFR to 52% above control (P = 0.03). Isolated SHR kidneys exhibited exaggerated GFR responses to verapamil but not to norepinephrine. Abnormal cell Ca regulation may underlie the marked decrease in GFR when SHR kidneys are perfused acutely at normotensive perfusion pressures.