Comparative discriminative stimulus effects of 5-methoxy-N,N-dimethyltryptamine and LSD.

Rats were trained to discriminate injections of either 5-OMe DMT (1.5 mg/kg) or LSD (0.096 mg/kg) from saline in a two-lever drug discrimination task. After stable discrimination performances were attained (greater than 85%) in each group, dose-response generalizations between the two groups of animals were examined. The results revealed that the 5-OMe DMT-stimulus response generalized to LSD and that the LSD-stimulus response generalized to 5-OMe DMT. Furthermore, both the 5-OMe DMT-stimulus and the LSD-stimulus could be significantly attenuated by the serotonin antagonist BC-105. However, the pattern of the dose-related antagonism by BC-105 was different between the drug stimuli. It was concluded that while the discriminative stimulus effects of 5-OMe DMT and LSD may be mediated via a common serotonergic system, the receptor interaction of these agents within that pharmacological system may be somewhat different.