Pentobarbital enhances [3H]diazepam binding to soluble receptors at the benzodiazepine--GABA-receptor-ionophore complex.

Pentobarbital enhances [3H]diazepam binding to soluble receptors in a dose-dependent and saturable manner. Half-maximal enhancement occurred at 110 micrometers pentobarbital. This enhancement was due to an increase in the affinity of diazepam to its receptor sites. Pentobarbital enhancement was blocked by picrotoxinin and bicuculline. These results are similar to those reported for membranes and suggest that various components of the benzodiazepine--GABA-receptor-ionophore complex are intimately associated.