Modular approach to modeling homotypic and heterotypic gap junctions

Gap junctions are intercellular pores allowing direct passage of ions and small molecules between adjacent cells. They are physiologically significant, playing important roles in cellular growth and tissue function. Most models of gap junctions focus on single channel currents. Here we present a model exhibiting macroscopic currents in homotypic gap junctions, and thereby allowing evaluation of cellular features. The technique is novel in its modular approach, whereby modules of hemi-channels are developed, followed by their serial combination to obtain the complete gap junction. It is an improvement over earlier models as it is able to demonstrate the phenomena of contingent gating. We present certain biophysical properties observed in a 3-D syncytium under different gap junction subtypes. Finally, we test the efficacy of this approach towards modeling of heterotypic gap junctions.