The role of tachykinin NK-1 receptors in the area postrema of ferrets in emesis.

The role of tachykinin NK-1 receptors in the area postrema (AP) in emesis was examined in ferrets. Strong c-fos-like immunoreactivity was observed in the AP and nucleus tractus solitalius (NTS) in cisplatin (10 mg/kg, i.p.)-treated animals, but not in control animals. The number of the central emetogen morphine-induced vomits and retches was remarkably reduced (95%) and that of the peripheral emetogen copper sulphate-induced vomits was significantly (54%) reduced by AP lesion. Pretreatment with the tachykinin NK-1 receptor antagonists HSP-117 (1.0 microg) and CP-99,994 (7.5 microg) into the AP decreased the numbers of vomits and retches induced by morphine and copper sulphate. These results suggest that NK-1 receptors in the AP are involved in the mechanism of emesis induced by morphine and copper sulphate.