INHIBITORY-ACTION OF THE DEFENSIVE DISCHARGE OF THE GRASSHOPPER, POECILOCERUS-PICTUS, ON CERTAIN ENZYMES LN THE LIZARD, CALOTES NEMORICOLA

Administration of the defensive secretion of the grasshopper, Poeciloc erus pictus inhibited acetylcholinesterase (AChE) and adenosine tripho sphatases (ATPases) in the brain and muscle tissues of the garden liza rd, Calotes nemoricola. The inhibition was gradual, continuous and irr eversible with lethal doses of the defensive secretion, whereas the in hibition observed with sublethal doses was followed by an increase tow ards control levels within 24 h after injection. In vitro application of defensive secretion also showed concentration-dependent inhibition in the activity of AChE and ATPases in the tissue homogenates. Inhibit ion in AChE activity might be a factor for the observed mortality in t he defensive fluid-treated lizards. Since the cardenolides are known t o inhibit the activity of ATPases, the inhibition in the activity of A TPases observed in the present study suggests the presence of cardenol ides in the defensive fluid of P. pictus.