Cisplatin-induced pica behaviour in rats is prevented by antioxidants with antiemetic activity.

Pica, eating of non-nutritive substances such as kaolin in rats has been suggested as an illness response behaviour, analogous to vomiting in species that have developed emetic reflex. We have recently demonstrated that antioxidants-glutathione, N-(2- mercaptopropionyl)glycine (tiopronin), vitamin C and vitamin E-exert antiemetic effect against cisplatin-induced emesis in dogs. In the present study, the effect of these antioxidants was investigated against pica model in rats. Pretreatment with these agents significantly inhibited the cisplatin induced enhanced kaolin intake. However, these agents failed to exert any significant improvement in the decreased food intake by cisplatin. The findings confirm the potential of these antioxidants as antiemetics against cancer chemotherapy induced vomiting, though they may not improve the anorexia. The experiments further support that pica in rats can be used as a good alternative rodent model to dogs and cats particularly for preliminary and rapid screening of antiemetic agents.