Fig. 4.

Effects of mutations on receptor activation by propofol and propofol analogs. The graph compares ratios (mean ± S.E.M.) of maximal responses to propofol or propofol analogs to responses to saturating pentobarbital in wild-type and mutant β3 receptors. Propofol was applied at 10–500 µM. Receptors containing the β3(F221W) mutation were not activated by propofol (#). Analogs were applied at 500 µM, except for 2-tert-butyl-6-methylphenol that was applied on β3(F221W) and β3(T266W) receptors at 10 µM. Pentobarbital was applied at 300 µM (wild type) or 3 mM (mutants). A value of 1 for the calculated parameter means that the compound/pentobarbital current ratio is the same in the mutant and wild type. The actual compound/pentobarbital current ratios for wild-type and mutant receptors are provided in the text. Statistical analysis (t test) was conducted by comparing the calculated parameter value to 1. The data show that the β3(Y143W) mutation does not affect the current ratio for 2-isopropylphenol or 2,6-dimethylphenol, and the β3(Q224W) mutation does not affect the current ratio for 2-isopropylphenol or 2-tert-butyl-6-methylphenol. *P < 0.05; **P < 0.01; ***P < 0.001; ns, not significant.