@article {TODA60, author = {NOBORU TODA}, title = {INFLUENCE OF CADMIUM IONS ON THE TRANSMEMBRANE POTENTIAL AND CONTRACTILITY OF ISOLATED RABBIT LEFT ATRIA}, volume = {186}, number = {1}, pages = {60--66}, year = {1973}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {In isolated rabbit left atria Cd++ (0.02-0.5 mM) caused a marked depression of the action potential and a slight decrease in time resting potential and the 10\% duration. In more than half of the atria exposed to 0.5 mM Cd++, action potentials were totally abolished with a slight reduction of the resting potential. Parameters of the transmembrarne potential recorded from control preparations were not affected by cysteine (1 mM). The inhibitory effect of Cd++ was partly reversed by cysteine, excess Ca++ and ethylene glycol bis(aminoethyl ether)-N,N,N{\textquoteright},N{\textquoteright}-tetraacetic acid. In atria in which action potentials were totally abolished by 0.5 mM Cd++, these agents restored the action potentials. Cysteine was the most effective. The contractile force-rate curve of left atria was significantly depressed by Cd++ (0.02 and 0.1 mM). The inhibitory effect of Cd++ was reversed by cysteine in concentrations insufficient, to alter contractility in control media and also by excess Ca++. It appears that the Cd++-induced depression of action potentials and contractions is due to binding with sulfhydryl groups in membrarnes and contractile proteins as well as interference with availability and inward movements of Ca++. It is concluded that membrane sulfhydryl groups may relate closely to the permeability of atrial cell membranes to Na+ and Ca++ during excitation. {\textcopyright} 1972 by The Williams \& Wilkins Co.}, issn = {0022-3565}, URL = {https://jpet.aspetjournals.org/content/186/1/60}, eprint = {https://jpet.aspetjournals.org/content/186/1/60.full.pdf}, journal = {Journal of Pharmacology and Experimental Therapeutics} }