2‐Pyrrolidinone in Human Cerebrospinal Fluid: A Major Constituent of Total γ‐Aminobutyric Acid

Abstract
2-Pyrrolidinone, the lactam of γ-aminobutyric acid (GABA), is identified as the major constituent of total GABA in human CSF. Structural elucidation was done by mass spectrometry. In lumbar CSF of four patients, 2-pyr-rolidinone represented about 54% of GABA found after acid hydrolysis, thus accounting for essentially all of the hitherto unknown GABA fraction in CSF.