“In guinea pig papillary muscles partially depolarized with 22 mM K+, DPN 205–734 in a concentration of 1 μM restored slow action potentials, which were then blocked by carbachol.”
“In rabbit papillary muscles the positive inotropic effect of DPN 205–734 (100 μM) was only moderately inhibited by carbachol (3 μM), suggesting an additional mechanism.”