Effects of Ramosetron on Gastrointestinal Transit of Guinea Pig

Abstract

Background/Aims A selective 5-hydroxytryptamine (5-HT) type 3 receptor antagonist, ramosetron, inhibits stress-induced abnormal defecation in animals and is currently used as a therapeutic drug for irritable bowel syndrome with diarrhea. The aim of this study is to investigate the effect of ramosetron on altered gastrointestinal (GI) transit. Methods Male guinea pigs weighing approximately 300 g were used. The effect of ramosetron was investigated on altered GI transit induced by thyrotropin-releasing hormone (TRH), 5-HT, or mustard oil (MO). GI transit was evaluated by the migration of charcoal mixture from the pylorus to the most distal point, and expressed as a percentage (%) of charcoal migration (cm) of the total length of total small intestine (cm). Results The average charcoal transit was $51.3{\pm}20.1%$ in the control (vehicle) group, whereas in the ramosetron group charcoal moved $56.6{\pm}21.9%$, $46.9{\pm}9.14%$ and $8.4{\pm}5.6%$ of the total small intestine at the concentrations of 10, 30 and $100{\mu}g/kg$, respectively. GI transit after administration of TRH ($100{\mu}g/kg$), 5-HT (10 mg/kg) or MO (10 mg/kg) was accelerated compared to vehicle (5-HT, $94.9{\pm}9.22%$; TRH, $73.4{\pm}14.7%$; MO, $81.0{\pm}13.7%$). Ramosetron inhibited GI transit altered by 5-HT, TRH or MO. Conclusions Ramosetron modulated GI transit. We suggest that ramosetron may be therapeutically useful for those with accelerated upper GI transit.

Keywords

• Gastrointestinal transit;
• Mustard oil;
• Ramosetron;
• Serotonin $5-HT_3$ receptor antagonist;
• Thyrotropin-releasing hormone