Background

The effects of lindane, a gamma-isomer of hexachlorocyclohexane, were studied on transmembrane potentials and currents of frog atrial heart muscle using intracellular microelectrodes and the whole cell voltage-clamp technique.

Results

Lindane (0.34 microM to 6.8 microM) dose-dependently shortened the action potential duration. Under voltage-clamp conditions, lindane (1.7 microM) increased the amplitude of the outward current (Iout) which developed in Ringer solution containing TTX (0.6 microM), Cd2+ (1 mM) and TEA (1 mM). The lindane-increased Iout was not sensitive to Sr2+ (5 mM). It was blocked by subsequent addition of quinidine (0.5 mM) or E 40-31 (1 microM).

Conclusion

In conclusion,our data revealed that lindane increased the rapid delayed outward potassium current which contributed to the AP repolarization of cardiac muscle.