Dopamine D2 Receptor and Dopamine Transporter mRNA Expression in Addicted Peripheral Blood Lymphocytes

Introduction: This study aimed to detect the effects of opioid addiction on the mRNA expression levels of the dopamine D2 receptor (DRD2) and dopamine transporter (DAT) in peripheral blood leukocytes. Methods: Four groups, each comprising 30 individuals, were included in the study: opioid-addicted, methadone-maintained (MM), long-term abstinent, and normal subjects. We measured the mRNA levels of DRD2 and DAT in peripheral blood leukocytes via real-time quantitative reverse transcription‒polymerase chain reaction (real-time RT‒PCR). Findings: The results of the study showed that DAT mRNA expression was not statistically significant in the affected subjects compared to the control group. Regarding DRD2, mRNA expression was increased significantly in the MM subjects compared to the control group (P=0.002). Conclusion: Our study could guide further research to refine the clinical applicability of biomarkers related to dopamine signaling proteins in opioid addiction.