Central serotonin 1A receptor binding in temporal lobe epilepsy: a [carbonyl-(11)C]WAY-100635 PET study

We performed positron emission tomography using [carbonyl-(11)C]WAY-100635, a serotonin 1A (5-HT(1A)) receptor antagonist, in 13 patients with temporal lobe epilepsy (TLE) and in 13 controls. 5-HT(1A) receptor distribution mapping allowed correct lateralization of the epileptogenic temporal lobe in all patients. 5-HT(1A) receptor binding potential (BP(ND)) was significantly reduced in almost all temporal regions of the epileptogenic lobe. Compared with controls, the patients had significantly decreased BP(ND) values in the hippocampus, parahippocampal gyrus, and amygdala. The asymmetry index (AI), which characterizes the interhemispheric asymmetry in BP(ND), was significantly higher in patients than in controls in most regions. Depression scores were not significantly correlated with BP(ND) or AI values. Our data provide further evidence of functional changes in the serotonergic system in TLE. Molecular imaging of the 5-HT(1A) receptor may help to define the in vivo neurochemistry of TLE, and may provide a valuable tool in the noninvasive presurgical assessment of patients with medically refractory TLE.