title: Glutamate levels in cerebrospinal fluid and triptans overuse in chronic migraine.
abstract: OBJECTIVE
  Chronic migraine (CM) is a common disorder, affecting 2% to 3% of the general population. Glutamate is implicated in cortical spreading depression, trigeminovascular activation, central sensitization, and may be linked to migraine chronification. Triptans brought a novel option for the acute migraine treatment. As the development of central sensitization impacts upon the effectiveness of triptan therapy, we hypothesized that glutamate might be related to triptan response mechanisms.
  
  
  METHODS
  We studied 19 patients diagnosed with CM according to the International Headache Society (2004) criteria. Patients were divided in those overusing analgesics (NSAIDs); those without overuse, and those overusing triptans.
  
  
  RESULTS
  Cerebrospinal fluid (CSF) glutamate levels were similar in patients overusing acute medications (0.335 +/- 0.225 micromol) compared to those without overuse (0.354 +/- 0.141 micromol), P= NS). In contrast, patients overusing triptans had CSF glutamate levels significantly lower than that observed in nonoverusers (0.175 +/- 0.057 vs 0.354 +/- 0.141 micromol, P= 0.015), and significantly higher than controls (0.175 +/- 0.057 vs 0.109 +/- 0.066 micromol, P= 0.039). In triptan overusers, CSF glutamate levels, although lower, were not significantly different from patients overusing other types of analgesics.
  
  
  CONCLUSIONS
  Our study showed lower glutamate levels in CSF of CM patients overusing triptans. Glutamate may be implicated in triptan response mechanisms, triptans may work in part by reducing extracellular glutamate levels in the brain.
authors.affiliation: Hospital Israelita Albert Einstein-Instituto Israelita de Ensino e Pesquisa-Instituto do Cérebro, São Paulo, Brazil.
authors.forename: Domingos Sávio deSouza
authors.initials: DS
authors.lastname: Vieira
authors.forename: Maria da Graça
authors.initials: Mda G
authors.lastname: Naffah-Mazzacoratti
authors.forename: Eliova
authors.initials: E
authors.lastname: Zukerman
authors.forename: Carlos Augusto
authors.initials: CA
authors.lastname: Senne Soares
authors.forename: Esper Abräo
authors.initials: EA
authors.lastname: Cavalheiro
authors.forename: Mario Fernando Prieto
authors.initials: MF
authors.lastname: Peres
mesh_terms: D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D018698:Glutamic Acid / Q000134:cerebrospinal fluid*; D020773:Headache Disorders / Q000134:cerebrospinal fluid / Q000188:drug therapy; D051271:Headache Disorders, Secondary / Q000134:cerebrospinal fluid / Q000188:drug therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000134:cerebrospinal fluid* / Q000188:drug therapy*; D010880:Piperidines / Q000008:administration & dosage / Q000009:adverse effects; D017366:Serotonin Receptor Agonists / Q000008:administration & dosage / Q000009:adverse effects*; D014230:Triazoles / Q000008:administration & dosage / Q000009:adverse effects*; D014363:Tryptamines / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D010880:Piperidines; D017366:Serotonin Receptor Agonists; D014230:Triazoles; D014363:Tryptamines; D018698:Glutamic Acid; C093622:rizatriptan; C106783:naratriptan