The effect of hypoxia on the mechanical activity of the canine small intestine

The effects of 4 hr. of hypoxia on the contractile activity of intact jejunal segments of unanesthetized animals was investigated by use of extraluminal force transducers. The frequency of contraction of the longitudinal and transverse axes was less than that in normal segments. Although spikes initiate contraction, the slow-wave frequency determines the maximal contractile frequency of both muscle layers. The myenteric plexus synchronizes the contractile patterns between muscle layers and coordinates contractile activity between adjacent intestinal segments. The plexus appears to regulate the level of intestinal tone.