DOM [ie, l-(2, 5-dimethoxy-4-methylphenyl)-2-aminopropanel is a 5-HTlcp serotonin agonist that exerts stimulus control of behavior in animals. In order to determine if the discriminative stimulus effect of DOM is 5-HTlc-or 5-HTz-mediated, it would be informative to conduct tests of stimulus antagonism with a 5-HTlc-or 5-HT2-selective antagonist. To date, no such agents exist. Although the neuroleptic agent spiperone binds at D2 dopamine receptors and B-HT ...