4-Methylamphetamine is a stimulant and anorectic substance in the phenethylamine and amphetamine chemical groups (4-MA; PAL-313; Aptrol; p-TAP).
In vitro, it serves as a potent and balanced release agent for serotonin, norepinephrine and dopamine with Ki affinity values of 53.4nM, 22.2nM and 44.1nM in transporters of serotonin, norepinephrine and dopamine, respectively. More recent in vivo experiments involving performing microdialysis on rats, however, have shown a different pattern. These studies have shown that 4-methylamphetamine is even more active compared to dopamine (~5 x baseline) in elevating serotonin (~18 x baseline). The authors hypothesized that this is because, by some mechanism, 5-HT release dampens DA release. For instance, because this is known to inhibit DA release, it was suggested that a possible cause for this may be activation of 5HT2C receptors. In addition, there are alternate reasons for encouraging GABA release, which has an inhibitory effect on DA neurons, such as 5-HT release.
In 1952, 4-MA was investigated as an appetite suppressant and a trade name, Aptrol, was even given, but research was apparently never completed. It has been identified recently as a novel designer drug.
In animal tests, 4-MA was shown to have the lowest self-administration rate out of a number of related drugs tested (3-methylamphetamine, 4-fluoroamphetamine, and 3-fluoroamphetamine were the others), presumably as a consequence of having the highest serotonin release capacity compared to dopamine.