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.
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