The enhancement of diazepam and muscimol binding by pentobarbital and (+)-etomidate: size of the molecular arrangement estimated by electron irradiation inactivation of rat cortex.

Synaptosomal membranes were prepared from frozen rat cortices irradiated by 10 MeV electrons and the enhancement of [3H]diazepam and [3H]muscimol binding by pentobarbital (PB) and (+)-etomidate was studied. The target sizes of the corresponding parts of the receptor complex were estimated from the decrease in the enhancement as a function of irradiation dose. Different radiation inactivation constants suggest different regulatory units for the enhancement by PB and (+)-etomidate. Target sizes for PB and (+)-etomidate enhancement of [3H]diazepam binding were 127 +/- 14 and 360 + 124 kDa, respectively.