THE EFFECTS OF 2,3-BUTANEDIONE MONOXIME ON INITIAL HEAT, TENSION, AND AEQUORIN LIGHT OUTPUT OF FERRET PAPILLARY-MUSCLES

At low concentrations (up to 5 mM) the compound 2,3-butanedione monoxime (BDM) was found to reduce twitch tension and initial heat production in isolated papillary muscles without significantly affecting the size of the intracellular Ca transient measured with aequorin luminescence. Higher concentrations of BDM caused further inhibition of twitch tension and heat production with a fall in the size of the Ca+ transient. The size of the aequorin transient was 50% of the control value at 15 mM BDM while twitch tension was negligible. These results suggest that BDM selectively inhibits Ca2+ activated force in cardiac muscle at low concentrations with additional effects on intracellular calcium at concentrations above 5 mM. © 1990 Springer-Verlag.