TABLE 3.

Pharmacological specificity of S-[³H]mTFD-MPPB photolabeling of γ2Ser-280 in α1β3γ2 GABA_AR (% control)

Incorporation in γ2-Ser-280 was quantified in experiments including those in Figs. 5A and 11 by measuring the ³H cpm recovery in fractions 21–23 from rpHPLC fractionations of EndoLys-C digests of 56-kDa gel bands from GABA_ARs photolabeled with S-[³H]mTFD-MPPB in the absence of other drugs (control) or in the presence of drugs. n is the number of photolabeling experiments.

+Bicuculline	+GABA	+Etomidate	+S-mTFD-MPPB	+Ivermectin	+Picrotoxinin
190 ± 110 (n = 3)	24 ± 5 (n = 3)	5 (n = 1)	5 (n = 1)	30 (n = 1)	140 ± 50 (n = 2)