Methamphetamine (metamfetamine) is a psychostimulant and sympathomimetic drug. It is mainly taken recreationally but can be taken for ADHD and exogenous obesity in the form of a drug called Desoxyn. Methamphetamine induces effects of euphoria and affects heart rate, body temperature, blood pressure, appetite, attention, mood, and responses associated with alertness or alarm conditions. The drug triggers mainly a fight or flight response in the body and brain. Methamphetamine acts on the serotonin pathway both in the brain and in the gastrointestinal tract. More than 90% of serotonin is produced in gut cells. It is synthesized from Tryptophan which synthesizes 5-Hydroxy-L-tryptophan which synthesizes serotonin or 5-hydroxytryptamine. The mechanisms in which methamphetamine acts on serotonin are very similar to that of dopamine and norepinephrine in the presynaptic neuron. Methamphetamine inhibits Amine oxidase [flavin-containing] A which when uninhibited metabolizes serotonin into 5-Hydroxyindoleacetic acid. The inhibition of this causes serotonin to accumulate in the cytosol. Like norepinephrine the methods are less tested than for dopamine. The high concentration of serotonin in the synapse activates 5-hydroxytryptamine receptor 2A, 3A, and 3B on the postsynaptic neuron membrane. Activation of 5-hydroxytryptamine receptors in the gut causes the smooth muscles around intestines to contract which causes food to pass through the intestine more quickly. The faster food passes through, the less nutrients absorbed into the blood stream which would help with exogenous obesity. In the brain, the mechanisms of 5-hydroxytryptamine receptor activation is not well understood, but it has been found that there is an effect on mood, perception, cognition, which can possibly help with ADHD.

Methamphetamine Serotonin Reuptake Inhibitor Pathway References