Pharmacology of gap junctions in the cardiovascular system.

Gap junction channels provide the basis for intercellular communication and play an important physiological role in the cardiovascular system for maintenance of the normal cardiac rhythm, regulation of vascular tone, endothelial function and myoendothelial interaction as well as for metabolic interchange between the cells. Thus, pharmacological influence on these channels might help to elucidate their role in physiology and pathophysiology and might reveal new therapeutic approaches. The gap junction conductance between two cells is defined by the number of channels, the single channel conductance and the mean open and closed time. In principle, it is possible pharmacologically to induce closing of the channels, to change preferred single channel conductance, to open channels (or to keep them open), and to regulate the expression, synthesis, assembly and degradation of the channels thereby controlling the number of channels. This review describes the various substances affecting these parameters and outlines the possible pharmacological use of such drugs.