Mechanistic studies on DOM as a discriminative stimulus.

Ten rats were trained to discriminate racemic DOM (1.0 mg/kg, IP) from saline using a standard two-lever operant procedure. Once responding was stable, these animals were administered doses of lisuride and the purported 5-HT1 agonist 8-OH DPAT in tests of stimulus generalization. DOM-stimulus generalization occurred with lisuride, but not with 8-OH DPAT. These animals were also administered doses of LY-53,857, ritanserin, CP-52,215, and THT in tests of stimulus antagonism. Each of these agents possesses a significant affinity for 5-HT2 binding sites, and each effectively attenuated the DOM-stimulus. These results, coupled with our earlier findings, support the hypothesis that DOM may be producing its stimulus effects via a 5-HT2-related mechanism.