Effect of malathion on some kinesiological parameters of the gastrocnemius muscle of frog, Rana hexadactyla (Lesson) and the antagonistic action of atropine

Selected kinesiological parameters were studied in the gastrocnemius muscle of frog, R. hexadactyla Lesson, under different treatments with malathion and atropine. There is an apparent decrease of twitch amplitude, half contraction time, half relaxation time, twitch duration and fatigue time in control muscle during malathion treatment. In the denervated muscle, twitch amplitude, latency period, and fatigue time were lowered, with elevated phases of contraction and relaxation time. However, all these parameters except fatigue time showed an elevatory trend when atropine was given along with malathion revealing its antagonistic action against malathion toxicity. All these results indicate that the action of malathion is similar to that of a pharmacologically active myo- and neurotoxic agent.