The role of 5-hydroxytryptamine(3) and 5-hydroxytryptamine(4) receptors inthe regulation of gut motility in the ferret

The role of 5-hydroxytryptamine (5-HT)(3) and 5-HT4 receptors in the regula tion of gut motility in the ferret was investigated. The selective 5-HT3 re ceptor antagonist ramosetron (1 - 10 mu g/kg s.c.) prolonged the interval o f gastric antral migrating motor complex, but had only slight effect on sma ll intestinal and colonic motility in unfed animals. The selective 5-HT4 re ceptor antagonist SE 204070 did not affect motility throughout gut in unfed animals. Neither ramosetron nor SE 204070 affected the motility throughout gut in fed animals. In conclusion, neither 5-HT3 nor 5-HT4 receptors tonic ally regulate ferret gut motility except that 5-HT3 receptors have a key ro le in the occurrence of migrating motor complex specifically in the stomach . The role of 5-HT3 and 5-HT4 receptor system in the regulation of gut moti lity in ferrets is similar to that in other mammalian species studied, incl uding humans. This similarity suggests that the ferret is a suitable model animal to study gut motor functions in humans. (C) 2000 Elsevier Science In c.