Several 7-substituted derivatives of N,N-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 5-OMe-7-Me-DMT possess a higher pA2, and 5,7-(OMe)2-DMT a lower pA2, than that of DMT itself. Like DMT, all three of these compounds produce behavioral effects in rats which are simila...