Ca super(2+) channel modulation by 8-bromocyclic AMP in cultured heart cells

Modulation of ion channels is of increasing interest as it is an important step in the regulation of cellular functions. The authors have analysed the effect of 8-bromocyclic AMP on Ca super(2+) channels in cultured cardiac cells by the patch-clamp method and report here that there was a large increase in the probability of opening of the channels. On the basis of a recently proposed kinetic reaction scheme they suggest that cyclic AMP-dependent phosphorylation of Ca super(2+) channels primarily promotes the forward rate constants which lead to the open state of a Ca super(2+) channel during depolarization.