Figure 2.

Post-SSRI treatment. Diagram depicting extracellular 5-HT concentration, 5-HTT expression, and 5-HT1A receptor expression across the 5-HTTLPR and 5-HTR1A genotypes after long-term SSRI treatment. Subsequent to somatodendritic downregulation of 5-HT1A autoreceptors, disinhibition of raphe neurons causes an increase in 5-HT release. A-C, However, genotypes that express fewer 5-HTTs or higher numbers of 5-HT1A receptors (B, C) show a reduced increase in extracellular 5-HT concentration when compared with the genotype that has higher 5-HTT levels and lower numbers of 5-HT1A receptors (A). D, The genotype expressing both reduced levels of 5-HTT and higher numbers of 5-HT1A receptors shows the smallest increase in extracellular levels of 5-HT.