Gene Expression Survey of Serotonin Receptors (5HTR2A and 5HTR3A) and Monoamine Oxidases Enzyme After Treatment With Methadone in Addicted Individuals

Background: Addiction disrupts the nervous system of the reward system, stimulus, and memory in the brain. The disruption of these systems in the brain causes biological, physiological, social, and psychological complications. Addiction is considered a psychological, social, and economic disorder in terms of medicine, psychology, and sociology, as well as philosophy, law, ethics, and religion. The most important place of narcotic effect is the brain, and receptors affect these substances. Dopamine and serotonin receptors are among the most important receptors, in which drugs affect them. Methadone is also an opiate drug that is even more addictive than morphine and heroin and is often used as a preservative to control heroin and narcotic addiction.Methods: In this study, 3 genes of 5-Hydroxytryptamine Receptor 2 A (5HT2Ra), 5-Hydroxytryptamine Receptor 3 A (5HT3Ra), and Monoamine Oxidases A (MAOA), which play an important role in serotonin function, were examined in Peripheral Blood Mononuclear Cells (PBMCs) of heroin addicts, who had been quitting addiction with methadone for 3 months. Therefore, peripheral blood PBMCs were isolated. cDNA was synthesized from mRNA; then, the expression of the gene was measured by real-time Polymerase Chain Reaction (PCR).Results: The expression of MAOA gene in the PBMCs of the addicted patients with methadone was significantly reduced compared to the control group, while the expression of 5HT2Ra and 5HT3Ra genes showed no change in the two groups.Conclusion: These results suggest that Methadone Maintenance Treatment (MMT) may be moderated by 5HT2Ra and 5 HT3Ra serotonin receptors and returned to their previous efficacy, but MAOA was significantly reduced.