ATTEMPTS TO CLASSIFY DEPENDENCE-LIABLE DRUGS BY USING A SIMPLE DRUG-DISCRIMINATION TEST IN MICE

1. In a simple discrimination test using a two compartment shuttle box with mice, we examined the action properties of dependence-liable dru gs. In mice trained to discriminate morphine from saline, neither meth amphetamine (MAP) nor cocaine (COCA) was generalized to the discrimina tive stimulus effects of morphine. 2. Similarly, in mice trained to di scriminate MAP from saline, COCA, which is known to have neuronal mech anisms in common with MAP, was generalized to the stimulus effects of MAP, but morphine was not. 3. Dihydroetorphine (DHE), which has recept or mechanisms in common with morphine, was generalized to the discrimi native stimulus effects of morphine, whereas it was not generalized to the effects of MAP. Thus, the present discrimination test might be us eful far the first screening of compounds with unknown neuronal mechan isms, particularly for classification into groups having separate neur opharmacological mechanisms in common. (C) 1998 Elsevier Science Inc.