IN-VIVO MOTILITY OF RAT COLON CHRONICALLY PRETREATED WITH SENNOSIDES

Ceco-colonic myoelectrical activity was investigated in rats pretreate d for 23 weeks by sennosides (10 or 40 mg/kg/day), Na-picosulfate (2.5 or 10 mg/kg/day) or laxative vehicle (control). On the last week of t reatment the animals were equipped with Nichrome electrodes on the cec um, the proximal and distal colon. In comparison with controls, sennos ide or Na-picosulfate treatment did not induce. any significant (p > 0 .05) change in the duration of long spike bursts (LSB) which are assoc iated with phasic contractions. On the last 2 days of treatment the fr equency of LSB for 2 h before and 2 h after laxative administration, a s well as for 30 min after a 3-gram meal was not significantly (p > 0. 05) different in control and treated animals. Similarly, on the first 2 days, as well as on days 13 and 14, after the end of treatment, no s ignificant (p > 0.05) difference in the LSB frequency appeared between control and treated animals, in the fasted state or after a 3-gram me al. It is concluded that long-term treatment with sennosides or Na-pic osulfate does not induce chronic changes in colonic motility in rats.