Benzodiazepine receptor modulation of [35S]TBPS binding to the chloride channel. Noncompetitive inhibition of classical benzodiazepines and competitive inhibition of the partial agonist, CGS 9895, by CGS 8216.

P Loo, A Braunwalder, P L Wood

Index: Neuropharmacology 26(7A) , 775-8, (1987)

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Abstract

Benzodiazepine receptor ligands are known to modulate the binding of [35S]TBPS to the chloride channel via an allosteric action. In the cases of diazepam, zopiclone and CGS 9895, the enhanced binding of [35S]TBPS induced by these benzodiazepine agonists was antagonized by CGS 8216. This antagonism was characterized both by a shift to the right and a decrease in the maximal stimulation, for the dose-response curves of diazepam and zopiclone. In the case of CGS 9895, the maximal response was not decreased. These data indicate that CGS 8216 is a noncompetitive antagonist of classical benzodiazepine receptor agonists but is a competitive inhibitor of the partial agonist, CGS 9895.