The effect of verapamil and diltiazem on cardiac stimulant effect of adrenaline and calcium chloride on isolated frog heart Sudhakar Lakhavat1, T Naveen Kumar2,*, NA Tadvi3, Y Venkata Rao4 1Non Medical Assistant, Kakatiya Medical College, Warangal, Andhra Pradesh, India 2Associate Professor, Department Pharmacology, Apollo Medical College, Hyderabad, A.P, India 3Associate Professor, Department Pharmacology, Kamineni Institute of Medical Sciences, Narketpally, Andhra Pradesh, India 4Professor and Head, Department Pharmacology, Kamineni Institute of Medical Sciences, Narketpally, Andhra Pradesh, India *Corresponding author Email: doctornaveen1@rediffmail.com
Abstract Background Calcium channel blockers block voltage dependent Ltype of calcium channel and thus reduce the frequency of opening of these channels in response to depolarization. The result is a marked decrease in transmembrane calcium current associated with long lasting relaxation of vascular smooth muscle, reduction in contractility in cardiac muscle, decrease in pacemaker activity in the SA node and decrease in conduction velocity in the AV node. Among Calcium channel blockers verapamil, is cardio selective, nifedipine is vascular smooth muscle selective, while diltiazem exhibits intermediate selectivity. Methods In the present study, the effect of two Ca++ channel blocker, Verapamil and Diltiazem were compared on the isolated frog heart by using adrenaline & calcium chloride as standard on frog heart contractility. Results and conclusion Adrenaline and calcium chloride increased the amplitude of contraction of isolated perfused frog heart. The Ltype of Ca2+ channel blockers verapamil and diltiazem produced dose dependent (2μg, 4μg, 8μg, and 16μg) reduction in the amplitude of contraction produced by calcium chloride in isolated perfused frog heart. There was no statistical significant difference (p > 0.05) between the inhibitory effect of diltiazem and verapamil on calcium chloride induced contraction of isolated frog heart. Top Keywords Verapamil, Diltiazem, Cardiac stimulant effect, Adrenaline, Cacl2. Top |