2,5-Dimethoxy-4-methylamphetamine (DOM)- a central component of its cardiovascular effects in rats; involvement of serotonin.

The hallucinogen DOM produces a rise in blood pressure and heart rate when injected into the cerebral ventricles of anesthetized rats. These effects are abolished in rats with transected spinal cords but are unaffected by prior treatment with hexamethonium. Central but not peripheral administration of the serotonin antagonist BOL reduces the response. Tachyphylaxis to the response develops rapidly and is accompanied by a decrease in the ability of 5-HT to induce a centrally mediated cardiovascular change. It is concluded that the response is mediated by direct stimulation of central 5HT receptors. Tachyphylaxis may be the result of irreversible binding of DOM to 5-HT receptors or to 5-HT receptor densensitization.