Nifedipine effectively lowers salt-induced high blood pressure in diabetic rats

This study examined the antihypertensive efficacy of nifedipine (a calcium channel blocker) in salt-loaded alloxan-diabetic rats. Significant increases in basal mean arterial blood pressures were observed after six weeks of high salt (8% NaCl) feeding in both diabetic (p < 0.05) and nondiabetic (p < 0.05) rats. The values were 129.95+/-3.14 mmHg for control (C); 149.22+/-8.83 mmHg for nondiabetic salt-fed (N-SF) and 150.60+/-8.01 mmHg for diabetic salt-fed (D-SF) groups. The non-salt-fed diabetic group (D) had a pressure of 136.75+/-6.66 mmHg. The maximum mean arterial blood pressures in response to noradrenaline (10(-9)-10(-5) M) infusion were significantly (p < 0.05) higher in the N-SF and D-SF groups than in the control. Nifedipine (100 microg/Kg) reduced significantly the pressures (both before and following noradrenaline infusion) in the salt-fed groups (p < 0.001). The inhibitory effect of nifedipine was more marked (p < 0.01) in the diabetic salt-fed than in the nondiabetic salt-fed. It is therefore suggested that nifedipine is effective in lowering salt-induced high blood pressure in diabetic rats.