Darragh Downey1, Gabriella Juhasz2, Shane McKie2, Karen Elizabeth Davies1, Emma Jane Thomas2, Diana Chase2, Rebecca Elliott2, John Francis William Deakin2, Ian Muir Anderson2, Stephen Ross Williams1
1Imaging Science and Biomedical Engineering, University of Manchester, Manchester, Lancashire, United Kingdom; 2Neuroscience and Psychiatry Unit, University of Manchester, Manchester, Lancashire, United Kingdom
We investigated whether citalopram-challenge phMRI, as a probe of serotonin transporter function, would detect functional variants of the serotonin transporter gene and how this may influence normal serotonergic function. 42 normal volunteers underwent phMRI with intravenous 7.5mg citalopram. Homozygous Short/Short allele carriers had reduced BOLD responses bilaterally in the caudate, mid-cingulate gyrus and parietal cortex and increases in the superior frontal gyrus compared with the Long/Long carriers. The results offer the first direct evidence that the short and long variants of the 5HTT promoter region indeed influence synaptic 5HT function in the living human brain.