Singh, R KGambhir, S S2009-05-282009-05-281992-12-01Singh RK, Gambhir SS. Comparative effects of mast cell degranulators on perfused systemic blood vessels of Bufo melanostictus and Rana tigrina. Indian Journal of Experimental Biology. 1992 Dec; 30(12): 1176-80http://imsear.searo.who.int/handle/123456789/59211Three agents known to induce release of mast cell constituents, viz. polymyxin, compound 48/80 and polysorbate-80, were evaluated for effect on perfused blood vessels of R. tigrina and B. melanostictus. The mast cell degranulators caused vasoconstriction in frog and toad, except that for P-80 whose responses in toad were equivocal. Toads showed a general low responsiveness in comparison to frogs. Pharmacologic intervention with pheniramine, metergoline, hydergine, atropine and mecamylamine, respectively ruled out role of histamine, 5-HT, catecholamine or acetylcholine or even autonomic mechanisms in the above phenomena. The observations are suggestive of phylogenetic differences in biochemical profile of mast cells in amphibian species.engAnimalsBufonidaeHistamine --pharmacologyHistamine AntagonistsMast Cells --drug effectsMuscle, Smooth, Vascular --drug effectsPerfusionPolymyxins --pharmacologyPolysorbates --pharmacologyRanidaeSerotonin --pharmacologyTachyphylaxisVasoconstriction --drug effectsp-Methoxy-N-methylphenethylamine --pharmacologyIn Vitro