Y. Sreenivasulu et al., INHIBITORY-ACTION OF THE DEFENSIVE DISCHARGE OF THE GRASSHOPPER, POECILOCERUS-PICTUS, ON CERTAIN ENZYMES LN THE LIZARD, CALOTES NEMORICOLA, Journal of enzyme inhibition, 11(2), 1996, pp. 135-140
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.