ABSTRACT
The effects of verapamil, a calcium channel blocker were examined on the norepinephrine and tyramine induced changes in mice myocardium. Tyramine but not norepinephrine [5 mg/kg/day, s.c. for 5 days] caused significant increase in cardiac mass reflected by increase ratios of heart wet and dry weights to body weight. The histopathological changes seen by light microscopy include cell necrosis and fibrosis with hypertrophied nuclei. Simultaneous treatment of the animals with verapamil [1 mg/kg/day, s.c. for 5 days] attenuated the above mentioned changes that were induced by catecholamines. Based on the data obtained in this study, it is proposed that catecholamines induced changes in the myocardium may involve facilitation of calcium entry which induce cell necrosis and lead to the development of dilated cardiomyopathy and verapamil is capable to attenuate these changes