Agonist-dependent internalization of gamma -aminobutyric acid sub(A)/benzodiazepine receptors in chick cortical neurons

An impermeant benzodiazepine receptor ligand was prepared by derivatization of the aminobenzodiazepine 1012-S with 4-sulfophenylisothiocyanate. The resulting N-(4-sulfophenyl)-thiocarbamoyl derivative of 1012-S (SPTC-1012S) was purified by reverse-phase HPLC, and the predicted structure was verified by mass spectrometry. The apparent affinity of SPTC-1012S for displacement of ( super(3)H)flunitrazepam from intact chick cortical neurons was similar to that of 1012-S. The results suggest that SPTC-1012S can be used as a probe to study the internalization of the GABA sub(A)/benzodiazepine receptor complex under normal conditions or following acute or chronic treatment with agonists.