CSF glutamate/GABA concentrations in pyridoxine-dependent seizures: Etiology of pyridoxine-dependent seizures and the mechanisms of pyridoxine action in seizure control

Tomohide Goto, Nobutake Matsuo, Takao Takahashi

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

Several lines of evidence suggest that the binding affinity of glutamate decarboxylase (GAD) to the active form of pyridoxine is low in cases of pyridoxine-dependent seizures (PDS) and that a quantitative imbalance between excitatory (i.e. glutamate) and inhibitory (i.e. γ-aminobutyric acid, GABA) neurotransmitters could cause refractory seizures. However, inconsistent findings with GAD insufficiency have been reported in PDS. We report a case of PDS that is not accompanied by an elevated cerebrospinal fluid (CSF) glutamate concentration. Intravenous pyridoxine phosphate terminated generalized seizures which were otherwise refractory to conventional anti-epileptic medicines. No seizure occurred once oral pyridoxine (13.5 mg/kg per day) was started in combination with phenobarbital sodium (PB, 3.7 mg/kg per day). The electroencephalogram (EEG) normalized approximately 8 months after pyridoxine was started. The patient is gradually acquiring developmental milestones during the 15 months follow-up period. The CSF glutamate and GABA concentrations were determined on three separate occasions: (1) during status epilepticus; (2) during a seizure-free period with administration of pyridoxine and PB; and (3) 6 days after suspension of pyridoxine and PB and immediately before a convulsion. The CSF glutamate level was below the sensitivity of detection (<1.0 μM) on each of the three occasions; the CSF GABA level was within the normal range or moderately elevated. The CSF and serum concentrations of vitamin B6-related substances, before pyridoxine supplementation, were within the normal range. We suggest that (1) PDS is not a discrete disease of single etiology in that insufficient activation of GAD may not account for seizure susceptibility in all cases and (2) mechanism(s) of anti-convulsive effect of pyridoxine, at least in some cases, may be independent of GAD activation.

Original languageEnglish
Pages (from-to)24-29
Number of pages6
JournalBrain and Development
Volume23
Issue number1
DOIs
Publication statusPublished - 2001 Feb 28

Keywords

  • Glutamate
  • Glutamate decarboxylase
  • Pyridoxine
  • Pyridoxine-dependent seizures
  • Vitamin B
  • γ-Aminobutyric acid

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Developmental Neuroscience
  • Clinical Neurology

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