Different Chronotropic and Inotropic Effects of EMD 57033 and EMD 53998, Ca2+ Sensitizers, on Isolated, Blood-Perfused Dog Heart Preparations

[摘要] References(13)Cited-By(1)To investigate whether a Ca2+ sensitizer increases sinus rate, we studied the effects of racemic thiadiazinone, EMD 53998 (a Ca2+ sensitizer with phosphodiesterase inhibitory action) and its (+)-enantiomer EMD 57033 (a relatively pure Ca2+ sensitizer) on isolated, blood-perfused spontaneously beating right atria and paced left ventricles of the dogs. EMD 53998 increased sinus rate dose-dependently, but EMD 57033 did not. Both substances increased atrial and ventricular contractile force. Propranolol did not affect the responses to each substance. These results suggest that the Ca2+ sensitizing action induced by EMD 57033 does not affect pacemaker currents directly.

[学科分类] 药理学

[关键词] EMD 57033;Ca2+ sensitizer;Sinus rate