Abstracts

Rationale: Depletion of 5-HT, with the consequent upregulation of its postsynaptic receptors, has been associated with epilepsy, as well as with depression. In this study, we evaluated the concentration of 5-HT in the hippocampus obtained from patients with MTS who underwent a surgery due to refractory epilepsy and correlated with epilepsy severity and presence of psychiatric disorders (PD). Methods: We studied 44 patients with MTS surgically treated (24 female; 35.0 + 13.1 years), 24 (54.5%) of whom had psychiatric comorbidities. After anterior temporal lobectomy, surgically ressected hippocampus samples were dissected and homogenized with 3.4M perchloric acid. We measured 5-HT using high-performance liquid chromatography with fluorescence detection. Results: The mean concentration of 5-HT was 0.3366 ng/mg. This concentration of 5 HT was lower in patients with GTC seizures (Student s t-test: p 0.041). Concentration of 5-HT was similar in patients with and without PD (Student s t-test: p 0.279). Moreover, 5HT levels were not related to age at onset or duration of epilepsy; seizure frequency; history of febrile seizures and status epilepticus. Conclusions: This study showed that lower concentrations of 5 HT were related to the severity of epilepsy (i.e., the presence of GTC seizures) but not to the presence of PDs. The relationship between serotonin and PDs probably involves mechanisms that are more intricate, such as pre and post synaptic transmission and/ or receptors.