The Pharmacological Regulation of Interstitial Cells of Cajal in the Small Intestine

Jun, Jae Yeoul

Abstract

It is now known that certain class of interstitial cells of Cajal (ICC) serves as pacemaker cells in the phasic portions of the gastrointestinal (GI) tract. They generate and propagate slow waves in gastrointestinal muscles via gap junctions. The electrical slow wave activity determines the characteristic frequency of phasic contractions of the stomach, intestine, and colon. The pacemaker areas are richly innervated with enteric motor nerves, and recent immunohistochemical and functional studies have shown that both excitatory and inhibitory enteric motor neurons are closely associated with ICC in the deep muscular plexus of the small intestine and intramuscular ICC of the proximal and distal GI tract. Furthermore, it was found that ICC express many neurotransmitter receptors utilized by enteric motor neurons. These observations imply a role for ICC in mediating neural inputs to the GI tract and in pharmacological regulation in GI tract. The role of the ICC and the enteric nervous system in the integrative control of gastrointestinal function and especially of spontaneous rhythmic activity is still unknown. Nevertheless, from the electrophysiological results presented in this review of studies of ICC, it is convincing that the ICC drive spontaneous rhythmic motility, and ICC could be the target for pharmacological interventions and the understanding and development of pharmacological study in ICC is a prerequisite for further analysis of GI motility disorders.