TASK-1 Inhibiition Assay: Human TASK-1 channels were expressed in Xenopus oocytes. For this purpose, oocytes were isolated from Xenopus laevis and defoliculated. Subsequently, TASK-1-encoding RNA synthesized in vitro was injected into the oocytes. After two days of TASK-1 protein expression, TASK-1 currents were measured by two-microelectrode voltage clamp. Data were acquired and analyzed using a TEC-10cx amplifier (NPI Electronic, Tamm, Germany) connected to an ITC-16 interface (Instrutech Corp., Long Island, USA) and Pulse software (HEKA Elektronik, Lambrecht, Germany). Oocytes were clamped to -90 mV and TASK-1 mediated currents were measured during 500 ms voltage pulses to 40 mV. Oocytes were continuously superfused with ND96 buffer containing 96 mM sodium chloride, 2 mM potassium chloride, 1.8 mM calcium chloride, 1 mM magnesium chloride, 5 mM 4-(2-hydroxyethyl)-piperazine-1-ethanesulfonic acid (HEPES; pH adjusted to 7.4 with sodium hydroxide). All experiments were performed at room temperature.