Effect of PMA optical isomers and 4-MTA in PMMA-trained rats

1-(4-Methoxyphenyl)-2-aminopropane (PMA) and its sulfur analog, 1-(4-methylthiophenyl)-2-aminopropane (4-MTA), have been misrepresented as the controlled substance analog, N-methyl-1-(3,4-methylenedioxyphenyl)-2-aminopropane (PMMA)-like stimulus effects in rats, we examined S(+)PMA, R(-)PMA and 4-MTA in rats trained to discriminate either PMMA (1.25 mg/kg) or (+)amphetamine R(-)PMA (ED50 = 0.4 mg/kg), whereas S(+)PMA produced a maximum of 72% PMMA-appropriate responding, 4-MTA (ED50 = 0.3 mg/kg) also substituted for PMMA, but 4-MTMA produced a maximum of only 36% PMMA-appropriate responding. None of the four agents substituted for (+)amphetamine. Hence, like MDMA, R(-)PMA and 4-MTA are capable of producing PMMA stimulus effects in rats, but unlike MDMA, neither agent substituted for (+)amphetamine. (C) 2002 Elsevier Science Inc. All rights reserved.