Cisplatin impairs fluid and electrolyte absorption in rat small intestine:a role for 5-hydroxytryptamine

Background-The antineoplastic drug cisplatin has been widely used for the t reatment of cancer in humans but its use has been limited by vomiting and d iarrhoea. Cisplatin releases 5-hydroxytryptamine into the gut which is thou ght to be the major mediator of cisplatin induced vomiting. Aim-To determine whether cisplatin affects fluid and electrolyte transport in rat jejunum and whether this change can be modulated by the 5-hydroxytry ptamine, receptor antagonist, ondansetron. Methods-Jejunal perfusion in rats in vivo was performed one hour after intr aperitoneal cisplatin (5 and 10 mg/kg) administration. The effect of pretre atment with subcutaneous ondansetron 300 mu g/kg was investigated. Results-Median net fluid absorption after cisplatin 10 mg/kg (67 mu l/min/g dry intestinal weight (interquartile range 46 to 100); n = 15) was reduced compared with controls (120 (107 to 151) mu l/min/g; n = 13; p<0.001). Ond ansetron reversed the impairment of jejunal fluid absorption produced by ci splatin to normal (161 (130 to 176) mu l/min/g; n = 11; p<0.001). Electroly te movement paralleled fluid movement. Jejunal histological examination of sections from cisplatin treated animals showed villus damage, which was not prevented by pretreatment with ondansetron. Conclusion-These findings suggest that diarrhoea during cisplatin therapy m ay be due to altered fluid transport in the small bowel. The reversal of fl uid transport to normal in the presence of a 5-hydroxytryptamine, receptor antagonist suggests that 5-hydroxytryptamine is a local mediator in the sma ll intestine.