Less is more: optimal myoendothelial communication entails less gap junctions (546.7)

Abstract

The myoendothelial junction (MEJ) has been assigned an integral role in the regulation of small resistance arteries. Efficient and proper information transfer between the endothelium and the smooth muscle cell (SMC) layer is thought to depend on a high density of MEJ and direct coupling facilitated by gap junctions (MEGJs) herein.In this study, we study how heterogeneity in distribution and number of MEGJs affects the electrical communication between cell layers. We redesigned a detailed computational model of an arteriole to allow for the introduction of heterogeneity in both the number and spatial distribution of MEGJs.In our first simulations, we maintained a contant total conductance of MEGJs across the arteriole, but reduced the number of MEGJs. If less than 20% of SMCs harbours an MEGJ, an increase in conduction strength is observed. However, reducing MEGJs also reduces the spatial control of membrane potential in the SMC layer. This may to some extent be ameliorated by an increase in SMC‐SMC coupling.Moreover, an decrease in electrical conductance between the cell layers increased electrical spread in the endothelium but limited the radial current flow into SMCs. Thus, reducing the number and conductance of MEGJs provides for a scenario where the SMC layer across a finite distance along the vessel receives a specific quanta of charge, i.e. no decay of signal is observed in the SMC layer. This may underlie the observation of non‐decaying conduction along small arterioles.We conclude that in contrast to common belief, a low MEGJ density enhances electrical spread along the vascular wall. Furthermore, low MEGJ density may underlie the observation of augmented conduction.