On the day of the experiment, flies of different sex, age, and genotype were allocated to vials ensuring equal numbers for the different treatment groups. Flies were exposed to volatile general anesthetics and oxygen at specific concentrations using a device that permits simultaneous exposure of up to eight groups of flies.14 (link) Volatile general anesthetics were administered using a Datex-Ohmeda Aestiva/5 anesthesia machine equipped with commercial agent-specific vaporizers (Datex-Ohmeda Inc., Madison, WI). Compressed gas cylinders (Airgas USA, LLC, Radnor, PA) containing 100% O2, 100% N2, or air (21%O2/79%N2) provided carrier gas of the desired composition. Anesthetic exposure consisted of either 2% isoflurane or 3.5% sevoflurane for 2 h at room temperature. Isoflurane and sevoflurane were obtained from Piramal Enterprises Ltd. (Maharashtra, India). To control for effects of circadian rhythm, flies were anesthetized at a similar time of day (between 10:00 AM and 2:00 PM).