Shotzberger_1976_J.Pharmacol.Exp.Ther_196_433

Reference

Title : The effects of batrachotoxin on cat papillary muscle - Shotzberger_1976_J.Pharmacol.Exp.Ther_196_433
Author(s) : Shotzberger GS , Albuquerque EX , Daly JW
Ref : Journal of Pharmacology & Experimental Therapeutics , 196 :433 , 1976
Abstract :

The effects of batrachotoxin (BTX) upon the contraction and transmembrane potential of cat right ventricular papillary muscles were studied in vitro at 37 degrees C. BTX (2.0 x 10(-9) M) increased isometric contractile force by about 50% from control force, decreased the potential difference across the cell membrane to approximate -50 mV and produced spontaneous contractions of the papillary muscles. Each BTX-induced spontaneous contraction was accompanied by a spontaneous action potential which was generated when an oscillation in membrane potential reached threshold level. Spontaneous activity ovvurred only in muscles which were previously stimulated electrically. The positive inotropic effect of BTX was accompanied by an increase in the rate of force development. Papillary muscles from cats pretreated with reserpine did not differ from normal muscles in their responses to BTX treatment. Tetrodotoxin (2.0 x 10(-7) M) antagonized the effects of BTX, a finding which suggests that the actions of BTX are mediated by a selective increase in membrane permeability to sodium ions. The resultant BTX-elicited increase in the intracellular sodium ion concentration may increase the force of contraction through an augmentation of calcium influx via the sodium-calcium exchange system.

PubMedSearch : Shotzberger_1976_J.Pharmacol.Exp.Ther_196_433
PubMedID: 1255486

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Citations formats

Shotzberger GS, Albuquerque EX, Daly JW (1976)
The effects of batrachotoxin on cat papillary muscle
Journal of Pharmacology & Experimental Therapeutics 196 :433

Shotzberger GS, Albuquerque EX, Daly JW (1976)
Journal of Pharmacology & Experimental Therapeutics 196 :433