Several 7-substituted derivatives of Nfl-dimethyltryptamine (DMT) were prepared and evaluated in the rat fundus serotonin receptor assay and in a behavioral (discriminative stimulus) assay in rats. Both 7-Me-and 50Me-7-Me-DMT possess a higher pA2, and 5, 7- (OMeI2-DMT a lower pAz, than that of DMT itself. Like DMT, all three of these compounds produce behavioral effects in rata which are similar to those of the hallucinogen 5-OMe- ...