Background: Nicotine decreases diarrhoea and pain in ulcerative colitis wit
hout reducing inflammation.
Aims: (i) To evaluate the effect of ulcerative proctosigmoiditis on motor f
unctions of an uninflamed segment of descending colon: and (ii) to assess n
icotine's effects on colonic motor functions in patients and healthy subjec
Methods: In healthy subjects (n = 30) and patients with ulcerative colitis
(13; 11 active, two quiescent colitis), we studied the effects of intraveno
us nicotine on colonic transit of solid residue by scintigraphy (healthy su
bjects) and on colonic motility in healthy subjects and 11 patients.
Results: In ulcerative colitis, fasting colonic motility was increased, whe
reas motor response to a meal was significantly reduced; compliance was unc
hanged, in healthy subjects, high-dose nicotine induced transient high ampl
itude propagated contractions and relaxation of the descending colon follow
ed by decreased phasic contractions. This dose also accelerated colonic tra
nsit. Low-dose nicotine (mimicking a transdermal nicotine patch) reduced co
lonic compliance in healthy subjects, but did not affect motor function in
Conclusions: Ulcerative proctosigmoiditis increases fasting colonic motilit
y and reduces tone response to a meal in the descending colon without affec
ting colonic compliance, suggesting changes in physiological responses but
not intrinsic wall properties. Nicotine has dose-dependent effects on colon
ic motor activity in healthy subjects.