Quinidine

The compounds assayed in this study and their concentrations are listed in Table 1. Isoproterenol, propranolol, digoxin, astemizole, moxifloxacin, dl-sotalol, flecainide, terfenadine and verapamil were purchased from Sigma-Aldrich. E-4031 was purchased from Enzo Lifesciences (Farmingdale, NY, USA). Milrinone, forskolin, quinidine and aspirin were purchased from Wako Pure Chemical Industries (Osaka, Japan). Lidocaine was purchased from Nacalai Tesque (Kyoto, Japan). Bay K 8644 was purchased from Abcam (Cambridge, MA, USA). Chromanol 293B was purchased from Tocris Bioscience (Bristol, UK). All reagents were dissolved in dimethyl sulfoxide (DMSO) (Wako Pure Chemical Industries). The final concentration of each compound in the culture medium was at most 0.5% v/v. Each concentration was tested in triplicate or quadruplicate.

Fetal bovine serum (FBS), Dulbecco's modified Eagle medium (DMEM), and Ham's F-12 nutrition mixture (F-12) were purchased from MP Biomedicals (Solon, OH). Penicillin-streptomycin, fungizone, and trypsin (1:250, powder) were purchased from Life Technologies (Carlsbad, CA). Percoll was purchased from GE Healthcare Bio-Science (Piscataway, NJ). [ 3 H]Nicotine was purchased from American Radiolabeled Chemicals, Inc. (St Louis, MO). p-Aminohippurate (PAH), L-carnitine, choline chloride, diphenhydramine, and verapamil were purchased from Nacalai Tesque Inc. (Kyoto, Japan). Nicotine, propranolol, pyrilamine maleate, pyrimethamine, quinidine, and quinine were purchased from Wako Pure Chemical Industries (Osaka, Japan). Procainamide and 1-methyl-4-phenylpyridinium (MPP þ ) were purchased from Sigma-Aldrich (St. Louis, MO). Tetraethylammonium chloride (TEA) and clonidine hydrochloride were purchased from Tokyo Kasei Kogyo Company (Tokyo, Japan). Cotinine was purchased from TOYOBO Company, Ltd. (Osaka, Japan). All other chemicals were of the highest grade commercially available.