Effects of HSP-117, a Novel Tachykinin NK1-Receptor Antagonist, on Cisplatin-Induced Pica as a New Evaluation of Delayed Emesis in Rats

The effects of a novel tachykinin NK1-receptor antagonist HSP-117 {(2S,3S)-3-[(5-isopropyl-2,3-dihydrobenzofuran-7-yl)methyl]amino-2-phenylpiperidine dihydrochloride} on cisplatin-induced pica, i.e., the eating of nonnutritive substances such as kaolin were examined in rats. HSP-117 inhibited kaolin intake in a dose-dependent manner for 2 days. The 5-HT3-receptor antagonist ondansetron inhibited only on the first day, but not on the second day. These results indicate that the cisplatin-induced kaolin intake on the first day is related to both 5-HT3- and NK1 receptors, while only the NK1 receptor is involved on the second day. Thus, cisplatin-induced continuous pica in rats represents a useful model of not only acute but also delayed emesis.