American Society of Anesthesiologists

Fig. 6.

Displacement of 3H-etomidate by dexmedetomidine (A), ketamine (B), and propofol (C). 3H-etomidate (2 nM) and the desired concentration of sedative-hypnotic were equilibrated with membranes. The mixture was then filtered, and radioactivity was measured in the washed filter. Each data point is the mean ± SD (n = 3) radioactivity measured in the washed filter. (A and B) The curves are fits of each data set to a competitive binding equation yielding half-inhibitory concentrations (IC50s) of 2.2 µM for dexmedetomidine and 79 µM for ketamine. An IC50 was not defined for propofol because we observed little concentration dependence, but the data set implies that it would be more than 100 µM. The final protein concentration was 0.07 mg/ml.

Displacement of ³H-etomidate by dexmedetomidine (A), ketamine (B), and propofol (C). ³H-etomidate (2 nM) and the desired concentration of sedative-hypnotic were equilibrated with membranes. The mixture was then filtered, and radioactivity was measured in the washed filter. Each data point is the mean ± SD (n = 3) radioactivity measured in the washed filter. (A and B) The curves are fits of each data set to a competitive binding equation yielding half-inhibitory concentrations (IC₅₀s) of 2.2 µM for dexmedetomidine and 79 µM for ketamine. An IC₅₀ was not defined for propofol because we observed little concentration dependence, but the data set implies that it would be more than 100 µM. The final protein concentration was 0.07 mg/ml.

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