Locomotor, discriminative stimulus, and place conditioning effects of MDAI in rodents.
5,6-Methylenedioxy-2-aminoindane (MDAI) has become a common substitute for (±)-3,4-methylenedioxymethamphetamine (MDMA) in Ecstasy. MDAI is known to produce MDMA-like discriminative stimulus effects, but it is not known whether MDAI has psychostimulant or hallucinogen-like effects. MDAI was tested for locomotor stimulant effects in mice and subsequently for discriminative stimulus effects in rats trained to discriminate cocaine (10 mgkg, intraperitoneally), methamphetamine (1 mgkg, intraperitoneally), ±MDMA (1.5 mgkg, intraperitoneally), or (-)-2,5-dimethoxy-4-methylamphetamine hydrochloride (0.5 mgkg, intraperitoneally) from saline. The ability of MDAI to produce conditioned place preference was also tested in mice. MDAI (3 to 30 mgkg) depressed locomotor activity from 10 to 60 min. A rebound stimulant effect was observed at 1 to 3.5 h following 30 mgkg. Lethality occurred in 88 mice following 100 mgkg MDAI. Similarly, MDMA depressed locomotor activity immediately following the administration of 0.25 mgkg and stimulant effects were observed 50-70 min following the administration of 0.5 and 1 mgkg. MDAI fully substituted for the discriminative stimulus effects of MDMA (2.5 mgkg), (-)-2,5-dimethoxy-4-methylamphetamine hydrochloride (5 mgkg), and cocaine (7.5 mgkg), but produced only 73% methamphetamine-appropriate responding at a dose that suppressed responding (7.5 mgkg). MDAI produced tremors at 10 mgkg in one methamphetamine-trained rat. MDAI produced conditioned place preference from 0.3 to 10 mgkg. The effects of MDAI on locomotor activity and drug discrimination were similar to those produced by MDMA, having both psychostimulant-like and hallucinogen-like effects thus, MDAI may have similar abuse potential as MDMA.