Endogenous benzodiazepine ligands in human cerebrospinal fluid.

Human cerebrospinal fluid was chromatographed on Bio-Gel P-4. Fractions containing material with molecular weights less than 4000 Dalton were pooled and further fractionated by high pressure liquid chromatography on an UltroPack TSK column G 2000 SW. At least three peaks, which were free of salt and GABA, were shown to displace (3H)-diazepam in the receptor-binding assay.