Effects of efonidipine hydrochloride (NZ-105), a calcium antagonist, on renal function in conscious spontaneously hypertensive rats

Abstract 1. 1. We investigated the effects of short- and long-term administration of efonidipine hydrochloride (NZ-105), 1,4-dihydropyridine derivative, in conscious spontaneously hypertensive rats (SHR). 2. 2. Oral administration of NZ-105 for 12 weeks caused diuretic and natriuretic effects, which were not attenuated during the experimental period. 3. 3. In the short-term experiment for investigating the mechanism of the diuretic effect, intravenous injection of NZ-105 (0.03 mg/kg of body weight) significantly increased the urine volume (UV), renal plasma flow (RPF) and glomerular filtration rate (GFR). The increment rate of UV and RPF was 105.4 ± 17.8% and 111.7 ± 72.8%, respectively, which were larger than the increment rate of GFR (38.5 ± 14.0%). 4. 4. The diuretic or natriuretic effect of NZ-105 was suggested to be due to both the inhibition of sodium reabsorption and, at least in part, the increase of GFR.