Cardiac gap junctions and action potential propagation

Described are the results, obtained from experiments on transfected cells to those on intact heart and new data are provided on connexin phosphorylation, expression and distribution. Transfected cells, regarded as the lowest level of complexity, are a very useful and reliable tool to study the effects of gap junction phosphorylation. To relate changes in gap junctional conductance to propagation of the action potential, isolated cardiomyocytes cultured in defined patterns are a promising model though experimental conditions have to be optimized. Finally, the mouse as a model to study impulse propagation in the intact heart has proven its applicability to unravel the physiological connection between connexin expression/distribution and impulse propagation. On the other hand, the mouse heart is in several respects substantially different from hearts of larger mammals, which hampers extrapolation of the acquired data