Serotonergic genes and amygdala activity in response to negative affective facial stimuli in Korean women

Serotonergic genes have been implicated in mood disorders, alcoholism and certain personality traits. We investigated the possible relationship between several polymorphisms in the serotonin (5-HT) system and amygdala responses to negative facial stimuli in Korean women using functional magnetic resonance imaging. All participants were genotyped with regard to the following polymorphisms: the serotonin transporter-gene-linked polymorphic region (5-HTTLPR), tryptophan hydroxylase 2 (TPH2) G(-703)T, 5-HT_1A C(-1019)G and 5-HT_2A single nucleotide polymorphism (SNP) rs6311. We found increased activations in response to angry facial stimuli in the bilateral amygdala of subjects with the long allele of 5-HTTLPR compared with those with two copies of the short allele. Higher activations in response to sad facial stimuli were found in the bilateral amygdala of subjects with the T/T genotype of 5-HT_2A SNP rs6311, compared with C allele carriers, and in subjects with the G/G genotype of TPH2 G(-703)T, compared with those with T/T and G/T genotypes. Our results for individuals from an Asian population countered a previous finding for a Caucasian population and identified the moderating role of genetic background in the relationships between these serotonergic gene polymorphisms and amygdala function elicited by negative emotional stimuli.