Evaluating a-synuclein, dopamine and serotonin concentrations in the blood of patients with heroin use disorder: Baseline and post-treatment comparisons

Abstract

Background. Oligomerization of a-synuclein is induced by serotonin aldehyde, and impulsive behaviour and substance use disorders may be associated with a-synuclein, dopamine and serotonin. Aim: We aimed to compare blood levels of a-synuclein, dopamine and serotonin in patients with heroin use disorder (HUD) and healthy individuals and to assess the possible effects of HUD treatment on the blood levels of these impulsivity-associated markers. Methods: 17 patients with HUD and 23 healthy volunteers were included in this study. All participants' baseline a-synuclein, 5-hydroxytryptamine (5-HT), dopamine, dopamine beta-hydroxylase (D.H), 5-hydroxy indole acetic acid (5-HIAA), homovanillic acid (HVA), and heat shock protein-70 (HSP-70) blood levels were measured. In patients with HUD, levels of these markers were measured after three weeks of buprenorphine treatment. Results: While the pre-and post-treatment HVA levels of the patient group were significantly higher (p=0.036), the pre-and post-treatment D.H (p<0.001), 5-HT (p<0.001) and dopamine (p<0.001) levels were significantly lower compared to controls. The patient group's post-treatment a-synuclein (p=0.044) levels were significantly higher than controls. With a cut-off value of <2000 ng/mL, DBH levels had a sensitivity of 94.1% and a specificity of 100.0% to detect patients with HUD. With a <251 pg/mL cut-off value, dopamine had 94.1% sensitivity and 82.6% specificity in distinguishing patients with HUD from controls. Conclusions: Dopamine and D.H may be helpful markers in diagnosing HUD. Understanding the influence of heroin use on these markers and pathways may enable their utilisation in assessing impulsive behaviour towards heroin.