The 5-HT1A receptor and 5-HT transporter in temporal lobe epilepsy

Objective: To study 5-HT transport and 5-HT1A receptors in temporal lobe epilepsy (TLE) and depression. Methods: Thirteen patients had PET with [ 11 C]DASB for 5-HTT and [ 18 F]FCWAY for 5-HT1A receptor binding, MRI, and psychiatric assessment. Sixteen healthy volunteers had [ 11 C]DASB, 19 had [ 18 F] FCWAY, and 6 had both PET studies. We used a reference tissue model to estimate [ 11 C]DASB binding. [ 18 F]FCWAY volume of distribution was corrected for plasma-free fraction. Images were normalized to common space. The main outcome was the regional asymmetry index. Positive asymmetry indicates relative reduced binding (reflecting transporter activity) ipsilateral to epileptic foci. Results: Mean regional [ 11 C]DASB binding and asymmetry did not differ between patients and controls. [ 18 F]FCWAY asymmetry was significantly greater for patients than controls in hippocampus, amygdala, and fusiform gyrus. On analysis of variance with region as a repeated measure, depression diagnosis had a significant effect on [ 11 C]DASB asymmetry, with significantly higher [ 11 C]DASB asymmetry in insular cortex (trend for fusiform gyrus). In insular cortex, patients had a significant correlation between [ 18 F]FCWAY asymmetry and [ 11 C]DASB asymmetry.