Effect of verapamil on uremic myocardial disease in the rat

It has been shown that calcium content of myocardium is increased in uremia and calcium overload has been implicated in the genesis of uremic myocardial disease. To determine whether verapamil (V) may prevent the development of myocardial lesions in uremic rats, the left ventricular myocardium has been examined with an electron microscope (EM) in 4 groups of Wistar male rats: 1) subtotally nephrectomized (SNX, n = 10); 2) SNX treated by V, 1.5 mg/kgx2/day (SNX-V, n = 8); 3) sham-operated (Sh, n = 5); 4) Sh treated by V (Sh-V, n = 5). EM examinations were performed after 13 weeks of uremia and V treatment. Serum urea and creatinine were similar in SNX and SNX-V rats and were higher in SNX and SNX-V than in Sh and Sh-V rats. The mitochondria of the myocardium in SNX rats showed damage of varying degree, starting from disrupted cristae to very dense mitochondrial structure with barely visible cristae. Myofibrils appeared disorganised with marked clear intermyofibrillar spaces. The myocardial ultrastructure of Sh, Sh-V and SNX-V rats was normal. It may be concluded that V seems to prevent the development of myocardial damage in the uremic rats.