Abstract

EFFECT OF PHYSOSTIGMINE ON CARDIOTONIC ACTIVITY OF PAROTOID GLAND SECRETION OF BUFO MELANOSTICTUS (SCHNEIDER) ON ISOLATED HEART OF FROG

Raju Neerati , Ankaiah Meesala, Samatha Talari , Prasad Neerati  andVenkaiah Yanamala *

Abstract

The present investigation was carried out to study the cardiotonic activity of parotoid gland secretion of common Indian Toad Bufo melanostictus on isolated perfused frog heart (Rana tigrina). The cardiotonic activity of parotoid gland secretion of B. melanostictus in normal as well as when induced with physostigmine (eserine) (an organophosphate) was studied. The cardiotonic activity was studied through Syme’s technique; digoxin and propranolol were used as standard drug and β-blocker respectively to characterize the effects on the receptors. The isolated perfused and hypodynamic heart of frog showed a dose dependent positive ionotropic effects. Cardiac stimulant activities were exhibited by the parotoid gland secretion on frog’s heart. Propranolol was unable to block the effect of physostigmine on toad parotoid gland secretion.Thus, the present investigation reports that the parotoid gland secretion increased the force of contraction, heart beat and cardiac output in perfused frog’s heart, whereas, there was no change on hypodynamic heart, indicating that there may be existence of two components, one with β– receptor stimulating activity and other acting directly on the frog’s heart (independent of β1- adrenoreceptors).

Keywords: Bufo melanostictus, Rana tigrina, Cardiotonic activity, Parotoid gland secretion, Physostigmine.