Availability of the serotonin transporter in patients with alcohol dependence

Abstract

Objectives. Evidence has suggested that the serotonin transporter (SERT) plays a role in the pathogenesis of alcohol dependence, anxiety and depression and that polymorphisms of the serotonin-transporter-linked promoter region (5-HTTLPR) may influence the SERT. This study evaluated the differences in SERT availability between healthy controls and alcoholic patients and the impact of 5-HTTLPR polymorphisms on SERT availability. Methods. Eleven healthy controls and 28 alcoholic patients were recruited. SERT availability was measured in vivo with single photon emission computed tomography and ¹²³I-labelled 2-((2-((dimethyl-amino)methyl)phenyl)thio)-5-iodophenylamine in the midbrain, thalamus and striatum. Each subject was genotyped for the 5-HTTLPR polymorphism. Results. Compared to healthy controls, there was a significantly lower availability of SERT in the midbrain among patients with pure alcohol dependence (pure ALC). Of patients with anxiety, depression and alcohol dependence (ANX/DEPALC), the carriers of one L_A allele showed a significantly higher availability of SERT in the striatum compared to non-L_A carriers. After Bonferroni correction, these significances vanished. There were no significant differences in SERT availability between controls and ANX/DEP ALC. Conclusions. The results suggest that pure alcoholics may have lower SERT availability in the midbrain; the 5HTTLPR polymorphism may influence SERT availability in ANX/DEP ALC. These findings may serve as a springboard for future large-scale studies.

Key words::

• Alcoholism
• serotonin transporter
• SPECT
• ¹²³I-ADAM
• 5-HTTLPR

Acknowledgements

This study was supported in part by National Science Council Grants NSC95-2314-B-016-019-MY2, NSC 97-2314-B-016-001-MY2 (S.Y.H) 98-NU-E-016-001-97WFE0100016 (S.W.H); by the Department of Health Grants DOH96-7D-D-113-031 (S.Y.H); and by Tri-Service General Hospital and National Defense Medical Center Grant TSGH-C97-88, TSGH-C98-8, 97 T26-06 (S.Y.H). The authors thank Miss. Fan-Yi Lin and Mr. Lie-Hang Shen, Mei-Hsiu Liao, Chia-Chieh Chen, Chen-Chang Huang for their assistance in the preparation of this manuscript.

Statement of interest

The authors have no conflict of interest with any commercial or other associations in connection with the submitted article.