Diabetic rat aorta responsiveness to D600 and nifedipine

1. The responsiveness of aortic rings from 4 and 12 week streptozotocin-induced diabetic rats to D600 (Gallopamil) and nifedipine was studied. 2. The sensitivity and responsiveness to D600 were significantly enhanced (P < 0.05; 5-test, ANOVA; 9 d.f.) only in the 4 week diabetic preparations precontracted with noradrenaline. 3. Nifedipine-induced relaxations were significantly enhanced (P < 0.05-0.01; t-test, ANOVA; 8-12 d.f.) in all the diabetic (4 and 12 weeks) aortic preparations precontracted with both noradrenaline (10(-7) mol/L) and KCl (40 mmol/L) when compared with controls. 4. D600, unlike nifedipine, did not produce significant relaxation of diabetic aortic preparations precontracted with KCl (40 mmol/L) at both week 4 and 12 of the disease when compared with controls. 5. These results suggest that there is differential responsiveness of streptozotocin diabetic rat aorta to D600 and nifedipine.