Abstracts

Rationale: Temporal lobe epilepsy (TLE) caused by hippocampal sclerosis (HS) is the leading cause of focal refractory epilepsy in adults (Qin et al., 2005). Depletion of serotonin (5-HT) with the consequent upregulation of its postsynaptic receptors has been associated with epilepsy in genetically epilepsy-prone rat (GEPR) model (Dailey et al., 1992; Jobe et al., 2000). Studies with animal models suggest that [5HT] and 5HT receptors are associated with epilepsy and epilepsy severity (Browning et al., 1997; Statinick et al., 1996) Evidences of anticonvulsant and antiepileptic effects associated with 5HT1A and 5HT2 receptors are contradictory (Bercovici et al., 2007; Péricç et al., 2005; Jakus et al., 2003; Watanabe et al., 2000; Gerber et al., 1998; Lösher & Czuczwar, 1995). To the moment, three studies in human tissue (Pallomero-Gallagher et al. 2012, Graebenitz et al., 2011, Yang et al 2012) evaluated the role of 5HT receptors in epileptgenesis, using heterogeneous samples, with contradictory results. Methods: We evalauted the hipocampal tissue of patients with refractory unilateral TLE-HS (24 female; mean age of 35.0 + 13.1 years) who underwent surgery. Semi-quantitative Western blotting procedure was used to identify the density of 5HT1A and 5HT2A receptors. Clinical variables studied were duration of epilepsy, age of onset, frequency of seizures and frequency of generalized tonic clonic (GTC) seizures, febrile seizures and status epilepticus. The relationship between receptor density and clinical variables was assessed by Spearman correlation and Wilcoxon-Mann-Whitney test. Results: The analysis of the density of 5HT1A was performed in 29 hippocampal samples and the density of 5HT2A in 24 hippocampal samples collected during surgery. There was no significant differences between the density of 5HT1A and 5HT2A and the clinical variables. Higher density of 5HT2A receptor was associated with higher frequency of GTC seizures, with a tendency to significance (p 0,041). Conclusions: Our findings showed in a homogeneous sample of patients with TLE-HS that serotonin receptors in hippocampus may play a role in severity of epilepsy (i.e., the presence of GTC seizures). The authors believe that clinical variables of epilepsy and comorbidities are multifaceted and different mechanisms are implicated in its pathogenesis