title: Effect of freezing on gamma-aminobutyric acid levels in human cerebrospinal fluid.
abstract: Using a radioreceptor assay, the concentration of gamma-aminobutyric acid (GABA) in human cerebrospinal fluid (CSF) was found to be elevated significantly following a single deep-freeze to --70 degrees C and thaw. Mean CSF GABA (+/- SD) in unfrozen CSF was 173 +/0 73 pmol/ml (n = 24). After a single deep-freeze, the mean level was 243 +/- 106 pmol/ml (p less than 0.02). Subsequent freeze-thaw cycles resulted in further irregular and unpredictable elevations in CSF GABA. Mean level after two freezes was 379 +/- 125 pmol/ml and after three freezes 654 +/- 411 pmol/ml. These changes could result in the incorrect interpretation of results in patients suffering from neurological diseases.
mesh_terms: D000328:Adult; D005615:Freezing; D006801:Humans; D008875:Middle Aged; D009422:Nervous System Diseases / Q000134:cerebrospinal fluid; D010300:Parkinson Disease / Q000134:cerebrospinal fluid; D013048:Specimen Handling; D005680:gamma-Aminobutyric Acid / Q000134:cerebrospinal fluid*
chemical_list: D005680:gamma-Aminobutyric Acid