FIGURE 5.

Summary of effects of GABA, PB, and SR-95531 on MTS second-order rate constants. Second-order rate constants (k₂) for MTS modification of cysteine mutants in the absence and presence of EC_80–90 GABA, 500 μm PB, 50 μm PB, or 10 μm SR-95531. k₂ values are reported in Table 2. Data are the mean ± S.E. from at least three independent experiments. ^* and ^** indicate values significantly different from control at p <0.05 and p <0.001, respectively. NFE (no functional effect) MTS reagent reacts with the cysteine mutant in the presence of PB but has no functional effect on subsequent GABA responses.