Synergistic antiemetic interactions between serotonergic 5-HT3 and tachykininergic NK1-receptor antagonists in the least shrew (Cryptotis parva)

► Blockade of either 5-HT3- or NK1-receptors reduce emesis caused by an agonist of each receptor. ► Relative to each antagonist tested alone, their combination is more potent against each emetogen. ► Combined doses of each agonist induce greater number of vomits relative to each emetogen alone. ► Emetic cross-talk occurs between serotonergic 5-HT3 and tachykininergic NK1 receptors. ► Synergistic antiemetic effects occur when combination antagonists are used against each emetogen.