The effect of bile acids on colonic myoelectrical activity.

The effect of different concentrations of sodium cholate, sodium chenodeoxycholate and sodium deoxycholate on colonic myoelectrical activity was studied in 4 dogs. There was no statistically significant difference in percentage motility, motility index, basal pressure or mean slow wave frequency with either cholic or chenodeoxycholic acid (5--15 mM). Deoxycholic acid (15 mM), however, caused a marked increase in percentage motility (median control value 4.1, range 0--23; after installation, median value 27--0, range 20.6--45.0, P less than 0.001). This was accompanied by an increase in spike activity, but no alteration in mean slow wave frequency or basal pressure was seen. Cholestyramine inhibited the motor response. It appears that only deoxycholic acid affects both motility and absorption, presumably by different pathways, and may thus assume importance in disorders of colonic motility.