Slow-wave Potential - in Gastrointestinal Smooth Muscle

In Gastrointestinal Smooth Muscle

In the gastrointestinal smooth muscle, a slow wave originates in the cells of Cajal as the basal electrical rhythm. Loss of these cells stops the propagation of a slow wave potential and thus gut motility. A slow wave threshold must be reached before a slow wave potential can propagate. The amplitude and frequency of the wave are modulated by intrinsic (Auerbach's plexus and Meissner's plexus) or extrinsic (sympathetic nervous system and parasympathetic nervous system) innervation or by hormones. Excitatory compounds include acetylcholine and substance P, inhibitory include vasoactive intestinal peptide and nitric oxide.

The frequency of slow waves also varies between sections of the intestinal tract. In small intestine, they occur at a rate of 10–20 per minute, while in the colon they occur at a slower rate of 3 to 8 per minute.