Behavioral characterization of alpha-ethyltryptamine, a tryptamine derivative with MDMA-like properties in rats.

Several reports have speculated that the tryptamine-derived drug alpha-ethyltryptamine (AET) may have effects similar to those of the amphetamine-derived drug 3,4-methylenedioxymethamphetamine (MDMA). Indeed, the US Drug Enforcement Administration has recently placed AET on the Schedule I list because of its putative similarity to MDMA. The Behavioral Pattern Monitor, which quantifies locomotor and investigatory responses of rats, was used to characterize the effects of AET in a paradigm that distinguishes between the effects of traditional hallucinogens, amphetamine-like stimulants, and MDMA-like drugs. First, a dose-response study revealed that all doses of AET tested (5, 10, 20 mg/kg) significantly increased locomotor activity. Locomotor hyperactivity is produced by MDMA or amphetamine-like stimulants, but not by classical hallucinogens, such as LSD or mescaline. Additionally, AET significantly decreased measures of investigatory behavior. Similar decreases occur with MDMA or hallucinogen administration. Second, as with MDMA, the locomotor hyperactivity induced by AET was attenuated by pretreatment (10 mg/kg) with the serotonin reuptake inhibitor fluoxetine. Thus, AET, a tryptamine-derived drug, appears to produce an MDMA-like profile of behavioral changes by virtue of releasing presynaptic serotonin.