Low-amplitude propagated contractile waves: a relevant propulsive mechanism of human colon.
BACKGROUND
Human colonic motility is still poorly understood, especially as far as concerns its propulsive function. Available data refer almost exclusively to the forceful propulsive activity, which is recognized as high-amplitude propagated contractions, the manometric equivalent of mass movements. By contrast, information on less vigorous propulsive contractions is still lacking.


OBJECTIVE
To investigate the presence and behaviour of low-amplitude propagated contractile waves (less than 50 mmHg in amplitude) in the colon of healthy humans during a 24-hour study period.


METHODS
A series of 16 healthy volunteers of both sexes entered the study, and were investigated by a standard technique involving a colonoscopically-positioned manometric catheter. During the study, two standard 1,000 kcal mixed meal and a 450 kcal breakfast were served. The recordings were, therefore, scanned for the presence of low-amplitude propagated contractile waves (waves of less than 50 mmHg in amplitude, propagated over at least three consecutive recording ports), their daily distribution, and their relationship with physiological events.


RESULTS
Low-amplitude propagated contractile waves were constantly present in all the tracings, with an average of about 61 events/subject/day and a mean amplitude of about 20 mmHg. More than 80% of these events appeared during the day, with a significant (p<0.05) increase after meals and after morning awakening. In 25% of subjects, these waves were accompanied by emission of flatus.


CONCLUSIONS
In the human colon, low-amplitude propagated contractile waves are a constant physiological propulsive pattern, which is generally related to sleep-wake cycles and meal ingestion.
Bassotti
G
G
Department of Clinical and Experimental Medicine, University of Perugia Medical School, Italy. gabassot@tin.it
Clementi
M
M
Antonelli
E
E
Pelli
M A
MA
Tonini
M
M
D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology; D003106:Colon / Q000502:physiology*; D004566:Electrodes; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology*; D006801:Humans; D008297:Male; D008365:Manometry / Q000295:instrumentation; D008875:Middle Aged; D019518:Postprandial Period / Q000502:physiology; D012016:Reference Values