Chronic in Situ Studies of the Electrical Activity of the Small Intestine

ONE OF the intrinsic properties of gastrointestinal smooth muscle is the spontaneous generation of electropotential changes. This phenomenon has been studied by several investigators since first described by Alvarez.¹ Most of these studies have been carried out in vitro, or as acute experiments on anesthetized animals, or on animals whose bowel has been moved from its normal position such as in the construction of Biebl loops.

Depending on the methods used and the electrode design, recordings are obtained which show either bursts of fast spike activity or slower, rhythmic variations in potential or both. The slow pattern has been called the "basic electric rhythm (BER)" by Bass et al,² but is referred to as simply "slow waves" by most authors. When both types of activity are seen together, the spikes are superimposed on the slow waves and in definite temporal relationship. It has been fairly well established that