title: Involvement of serotonin transporter gene polymorphisms (5-HTT) in impulsive behavior in the japanese population.
abstract: The serotonergic pathway has been implicated in the pathogenesis of impulsivity, and sensitivity to aversive outcomes may be linked to serotonin (5-HT) levels. Polymorphisms in the gene that encodes the serotonin transporter (5-HTT), which have differential effects on the level of serotonin transmission, display alternate responses to aversive stimuli. However, recent studies have shown that 5-HT does not affect motor function, which suggests that the functioning of the serotonin-transporter-linked polymorphic region (5-HTTLPR) does not directly affect the behavioral regulatory process itself, but instead exerts an effect via the evaluation of the potential risk associated with particular behavioral outputs. The aim of the present study was to examine the effect of specific 5-HTTLPR genotypes on the motor regulatory process, as observed during a Go/Nogo punishment feedback task. 5-HTT gene-linked promoter polymorphisms were analyzed by polymerase chain reaction, using lymphocytes from 61 healthy Japanese volunteers. Impulsivity was defined as the number of commission errors (responding when one should not) made during a Go/Nogo task. We found that the s/s genotype group made fewer impulsive responses, specifically under aversive conditions for committing such errors, compared to those in the s/l group, without affecting overall motor inhibition. These results suggest that 5-HTTLPRs do not directly affect the behavioral regulatory process itself, but may instead exert an effect on the evaluation of potential risk. The results also indicate that under such aversive conditions, decreased expression of 5-HTT may promote motor inhibitory control.
authors.affiliation: Graduate School of Education, Kyoto University, Yoshida Hon-machi, Sakyo-ku, Kyoto, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Nomura
authors.affiliation: Department of Biochemistry, Graduate School of Biomedical and Health Sciences, University of Hiroshima, Minami-ku, Hiroshima, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kaneko
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, Chiba Institute of Science, Choshi, Japan.
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Okuma
authors.affiliation: Department of Biomedical Research, Graduate School of Biomedical and Health Sciences, University of Hiroshima, Minami-ku, Hiroshima, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Nomura
authors.affiliation: Department of Psychiatry, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kusumi
authors.affiliation: Department of Psychiatry, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Koyama
authors.affiliation: Department of Pharmacology, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Nomura
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D007175:Impulsive Behavior; D008297:Male; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D012701:Serotonin / Q000378:metabolism; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D012701:Serotonin