Fig. 1. Direct activation of GABAAreceptors by 10 μM etomidate and 19 μM propofol is equal. Three current traces recorded from a single oocyte expressing α1β2γ2L γ-aminobutyric acid type A (GABAA) receptors are displayed, illustrating how equiefficacious solutions of etomidate and propofol were identified. Currents were sequentially activated by superfusion with 10 μM etomidate (ETO) or 19 μM propofol (PRO) as illustrated by the bars above each trace (solid = ETO; open = PRO), and the oocyte was washed for 15 min between traces. The current amplitudes change slightly over time, necessitating control ETO applications both before and after the experimental PRO. The maximum current elicited with 19 μM PRO (arrow ) is approximately the average of the ETO-elicited control currents before and after (dashed lines ). Current activation with PRO was significantly slower than with ETO. ETO = etomidate; PRO = propofol.