Nuclear Magnetic Resonance Detection of Increased Cortical GABA in Vigabatrin‐Treated Rats In Vivo

Summary: 1H Nuclear magnetic resonance ([1H]NMR) spectroscopy was used to detect elevation of γ‐aminobutyric acid (GABA) in rat brain after administration of the antiepileptic drug vigabatrin (VGB). Rats were treated for 3 weeks with VGB added to their drinking water to deliver a dose of 250 mg/kg body weight per day. NMR spectroscopy was performed noninvasively in vivo, and a GABA concentration of 6.0 ± 2.3 mmol/kg wet weight (mean ± SD, n = 5) was measured. GABA could not be detected in control animals in vivo. Postmortem GABA levels of 1.3 ± 0.5 and 4.5 ±l 1.0 mmol/kg (mean ± SD, n = 5) were measured in perchloric acid extracts of frozen brain from control and treated animals, respectively. Noninvasive measurement of increased cerebral GABA should allow detailed studies of the pharmacology of GABA‐increasing drugs in vivo. With future developments, these measurements may be feasible in human subjects.