Pharmacological characterization of cyclosporine A-induced kaolin intake in rats

Kaolin intake behavior of rats is known to be one of the useful animal models to evaluate the emetic and antiemetic actions of drugs. The present study was aimed at elucidating the pharmacological characterization of cyclosporine A (CsA)-induced kaolin intake in rats. Subchronic treatment (once a day for 3 days) with CsA produced a dose- and time-dependent increase in kaolin intake. Scopolamine (muscarinic antagonist), mepyramine (selective histamine H(1) antagonist) and diphenhydramine (H(1) and muscarinic antagonist) but neither domperidone (dopamine D(2) antagonist) nor ondansetron (serotonin 5-HT(3) antagonist) significantly inhibited CsA-induced kaolin intake. These findings suggest that an activation of central muscarinic and H(1) receptor is closely associated with CsA-induced kaolin intake in rats. Use of scopolamine and/or diphenhydramine may be possible regimens to alleviate and avoid nausea and vomiting in patients with CsA therapy.