Brain homocarnosine and seizure control of patients taking gabapentin or topiramate.
OBJECTIVE
To assess the relation between seizure control and brain homocarnosine and gamma-aminobutyric acid (GABA) levels of patients with complex partial seizures taking gabapentin (GBP) or topiramate (TPM) as adjunctive therapy.


METHODS
In vivo measurements of GABA and homocarnosine were made of a 14-cc volume in the occipital cortex by using (1)H spectroscopy with a 2.1-Tesla magnetic resonance spectrometer and an 8-cm surface coil. Poor seizure control was defined as more recent seizures than the median for the two groups of patients studied.


RESULTS
Homocarnosine levels were higher in patients with better seizure control than in those with poor control. No differences were found in the intracellular GABA levels between the patients who responded to GBP or TPM compared with those who did not.


CONCLUSIONS
In the visual neocortex, which is remote from the presumed seizure-onset zone, higher homocarnosine levels were associated with better seizure control in the patients taking GBP or TPM as adjunctive therapy; elevated intracellular GABA levels appeared to offer no additional protection.
Petroff
Ognen A C
OA
Department of Neurology, Yale University, New Haven, Connecticut 06520-8018, USA. ognen.petroff@yale.edu
Hyder
Fahmeed
F
Rothman
Douglas L
DL
Mattson
Richard H
RH
D000328:Adult; D000588:Amines / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D000927:Anticonvulsants / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D001923:Brain Chemistry / Q000187:drug effects; D002336:Carnosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D003509:Cyclohexanecarboxylic Acids / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D017029:Epilepsy, Complex Partial / Q000188:drug therapy* / Q000378:metabolism / Q000517:prevention & control; D005260:Female; D005632:Fructose / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D000077206:Gabapentin; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D019579:Neocortex / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D000077236:Topiramate; D016896:Treatment Outcome; D014793:Visual Cortex / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000032:analysis / Q000378:metabolism / Q000493:pharmacokinetics* / Q000627:therapeutic use*
D000588:Amines; D000927:Anticonvulsants; D003509:Cyclohexanecarboxylic Acids; D000077236:Topiramate; D005632:Fructose; C005038:homocarnosine; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D002336:Carnosine