[Endogenous inhibitors of the specific binding of benzodiazepines in the cerebral cortex].

The nature of inhibitors of [3H]-diazepam (D) specific binding (SB) was studied in 2 fractions of acidic extract from bovine brain cortex. Preparative high-performance liquid chromatography (HPLC), mass spectrometry, UV and IR techniques identified hypoxanthine and inosine as inhibitors of SB D. These substances may participate in the neuronal activity control which is in part mediated by the benzodiazepine receptors.