Slow potential variations of small intestine

Abstract

The various configurations of externally recorded slow waves from the small intestine of the cat are compared to those recorded intracellularly. It is shown that the slow waves represent periodic depolarizations of longitudinal muscle cells and that the flow of current associated with these depolarizations is similar to that in a core conductor. By recording monopolarly from a segment of intestine immersed in a volume conductor, slow waves are obtained having configurations ranging from those approximating the true time course and polarity of the intracellular slow wave to those approximating its second time derivative. This is shown to be a function of the pressure exerted by the electrode on the tissue. From a consideration of these results, plus those recently obtained by others, it is suggested that both "propagation" and synchronization of slow waves are manifestations of a modulation of slow wave discharge brought about either by electrotonic spread of current via low resistance intercellular pathways, or by voltage field effects.