Igor pro software

Electrophysiological responses were recorded using an automated patch-clamp Patchliner Octo^® system (Nanion Technologies, Munich, Germany) equipped with two EPC-10 Quadro patch-clamp amplifiers (HEKA Elektronik, Lambrecht, Germany) as described previously [2 (link)]. Chinese hamster ovarian (CHO) cells stably expressing human α4β2 nAChRs (Charles River Laboratories, Wilmington, MA, USA) were used. All experiments were performed at room temperature (24 °C) and repeated at least three times. Data were analyzed using Patchmaster software (HEKA Elektronik). Offline data analysis was performed in Apache OpenOffice™ (v4.1.2; Microsoft, Redmond, WA, USA). Igor Pro software (v6.2.2.2; WaveMetrics, Lake Oswego, OR, USA) was used to determine EC₅₀ values. The efficacy of the compounds was calculated by first normalizing the current induced by each compound by the internal acetylcholine control. These values were then expressed as a percentage of maximum receptor activation by nicotine. The average values were then fitted to the Hill equation:  $I=\text{Baseline}+\left(X^{\wedge }nH\right)({\text{I}}_{max}-\text{Baseline})/\left(X^{\wedge }nH+EC{50}^{\wedge }nH\right),$ where I is the current response, Baseline is the minimal current response, X is the agonist concentration, nH is the Hill coefficient, I_max is the maximal current, and EC₅₀ is the agonist concentration producing half-maximal activation. Data are presented as mean ± SD.