The actions of trimetazidine on nerve and muscle cells in frogs

The effect of trimetazidine (TMZ) on cardiac, skeletal muscle fibres and sympathetic ganglion cells in frogs were studied. In cardiac muscles, the contraction was depressed and the duration of action potentials were shortened by 1.5 mM TMZ. In skeletal muscles, the contraction induced by motor nerve stimulations was depressed by 0.3 mM TMZ, and the amplitude of end-plate potentials was decreased under this condition. The nicotinic transmission in sympathetic ganglia was inhibited by 0.003 mM TMZ, but the muscarinic transmission was not affected by 1.5 mM TMZ. In a Na-free TEA solution, prolonged action potentials (TEA potentials) of sympathetic ganglion cell, which appeared to be produced by an inward Ca movement across the membrane, were shortened by 1.5 mM TMZ. These results suggest that TMZ has a dual action, namely 1) a blocking action of nicotinic transmissions and 2) a blocking action of Ca movement during the generation of action potentials.