title: Hippocampal serotonin depletion is related to the presence of generalized tonic-clonic seizures, but not to psychiatric disorders in patients with temporal lobe epilepsy.
abstract: OBJECTIVE
  Previous studies suggest that concentration of serotonin ([5-HT]) plays a pathogenic role in various types of epilepsy inhibiting seizures. However, most have not considered the clinical variables of epilepsy, and all of these studies included small and heterogeneous samples with refractory epilepsy, regardless of etiology. In this work, we measured [5-HT]s in hippocampal tissues from a large series of patients with refractory temporal lobe epilepsy caused by hippocampal sclerosis who underwent epilepsy surgery and evaluated the relationship between [5HT] and epilepsy-related clinical variables and psychiatric disorders.
  
  
  METHODS
  We included 44 patients with refractory unilateral TLE-HS who underwent surgical treatment for epilepsy. Hippocampal samples were collected, and serotonin concentrations were measured with high-pressure liquid chromatography (HPLC).
  
  
  RESULTS
  Lower [5-HT]s were correlated with a history of GTC seizures (Student's t-test: p 0.041). There were no differences in [5-HT]s according to the other clinical variables and the presence of psychiatric disorders.
  
  
  CONCLUSIONS
  Our findings demonstrated that serotonin depletion in the hippocampus play an important role in some aspects of the severity of epilepsy (i.e., the presence of GTC seizures) in a homogeneous sample of patients with refractory temporal lobe epilepsy determined by hippocampal sclerosis, but not with the presence of psychiatric disorders.
authors.affiliation: Laboratory of Clinical Neurophysiology, Institute of Psychiatry, University of São Paulo School of Medicine Hospital das Clínicas, São Paulo, SP, Brazil. Electronic address: nataschafonseca@gmail.com.
authors.forename: Natascha C
authors.initials: NC
authors.lastname: da Fonseca
authors.affiliation: Laboratory of Neuroscience, Institute of Psychiatry, University of São Paulo School of Medicine Hospital das Clínicas, São Paulo, SP, Brazil.
authors.forename: Helena P G
authors.initials: HP
authors.lastname: Joaquim
authors.affiliation: Laboratory of Neuroscience, Institute of Psychiatry, University of São Paulo School of Medicine Hospital das Clínicas, São Paulo, SP, Brazil.
authors.forename: Leda L
authors.initials: LL
authors.lastname: Talib
authors.affiliation: Laboratory of Clinical Neurophysiology, Institute of Psychiatry, University of São Paulo School of Medicine Hospital das Clínicas, São Paulo, SP, Brazil; Laboratory of Neuroimaging, Institute of Psychiatry, University of São Paulo School of Medicine Hospital das Clínicas, São Paulo, SP, Brazil.
authors.forename: Silvia
authors.initials: S
authors.lastname: de Vincentiis
authors.affiliation: Laboratory of Neuroscience, Institute of Psychiatry, University of São Paulo School of Medicine Hospital das Clínicas, São Paulo, SP, Brazil.
authors.forename: Wagner F
authors.initials: WF
authors.lastname: Gattaz
authors.affiliation: Laboratory of Clinical Neurophysiology, Institute of Psychiatry, University of São Paulo School of Medicine Hospital das Clínicas, São Paulo, SP, Brazil; Laboratory of Neuroimaging, Institute of Psychiatry, University of São Paulo School of Medicine Hospital das Clínicas, São Paulo, SP, Brazil; Center for the Support of Research in Applied Neuroscience, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Kette D
authors.initials: KD
authors.lastname: Valente
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002851:Chromatography, High Pressure Liquid; D003863:Depression / Q000150:complications / Q000378:metabolism*; D004833:Epilepsy, Temporal Lobe / Q000150:complications / Q000378:metabolism* / Q000601:surgery; D005260:Female; D006624:Hippocampus / Q000378:metabolism* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D011618:Psychotic Disorders / Q000150:complications / Q000378:metabolism*; D012640:Seizures / Q000150:complications / Q000378:metabolism* / Q000601:surgery; D012701:Serotonin / Q000172:deficiency*; D055815:Young Adult
chemical_list: D012701:Serotonin