Figure 2. Etomidate, pentobarbital, or alphaxalone enhancement of potassium chloride-evoked [(3) H][Greek small letter gamma]-aminobutyric acid (GABA) release. Synaptosomes were superfused with 15 mM potassium chloride +/− etomidate (2-50 [micro sign]M), pentobarbital (10-200 [micro sign]M), or alphaxalone (2-50 [micro sign]M) during 6-10 min of superfusion. Curves show peak [(3) H]GABA release (mean +/− SEM) as a percentage of potassium chloride control (without anesthetic). The median effective concentration values of etomidate, pentobarbital, and alphaxalone to enhance potassium chloride-evoked [(3) H]GABA release were 10.1 +/− 2.1 [micro sign]M, 18.8 +/− 5.7 [micro sign]M, and 4.4 +/− 2.0 [micro sign]M, respectively. *P < 0.05, **P < 0.01 versus potassium chloride alone (n = 4-6).