Motor responses of human gastrointestinal tract to 5-hydroxytryptamine in vivo and in vitro

JJ Misiewicz, SL Waller, M Eisner - Gut, 1966 - ncbi.nlm.nih.gov
JJ Misiewicz, SL Waller, M Eisner
Gut, 1966ncbi.nlm.nih.gov
EDITORIAL SYNOPSIS This paper reports studies on the effects of serotonin on
gastrointestinal motility in vivo and on muscle strips in vitro. Serotonin stimulates upper and
lower small intestinal motility but inhibits activity in the stomach and colon. This effect is
apparently a direct one on the smooth muscle. These studies fit in well with the observed
effect in man in the carcinoid syndrome, as patients with increased urinary excretion of
5HIAA have been shown to have hypermotility of the small intestine and hypomotility of the …
EDITORIAL SYNOPSIS This paper reports studies on the effects of serotonin on gastrointestinal motility in vivo and on muscle strips in vitro. Serotonin stimulates upper and lower small intestinal motility but inhibits activity in the stomach and colon. This effect is apparently a direct one on the smooth muscle. These studies fit in well with the observed effect in man in the carcinoid syndrome, as patients with increased urinary excretion of 5HIAA have been shown to have hypermotility of the small intestine and hypomotility of the colon.
The alimentary tract is the main source of 5-hydroxytryptamine (5HT, serotonin) in the body, but the physiological role of this amine isas yet uncertain. Bulbring and Crema (1958) have shown that 5HT potentiates the peristaltic reflexwhen applied to the mucosal surface of the guinea-pig ileum in vitro. In man, intravenous injections of serotonin stimulate pressure waves in the jejunum and ileum (Hendrix, Atkinson, Clifton, and Ingelfinger, 1957) but inhibit the distal colon (Fink and Friedman, 1960). It is possible therefore that serotonin causes the ali-mentary symptoms of the carcinoid syndrome. In vitro, 5HT contracts human muscle strips from the small intestine but inhibits strips from the colon (Fishlock and Parks, 1963). The application of in vitro techniques to the study of human alimentary muscleis an important advance, but cannot replace studies in vivo. We havetherefore investigated the effect of 5-hydroxytryptamine both in vivo and in vitro on the stomach, small intestine, and colon. In addition, experiments were performed on strips of oesophageal muscle in vitro. We have also recorded the motility of thesmall intestine and colon in a patient with the carcinoid syndrome.
ncbi.nlm.nih.gov