Cellstar ps 96 well cell culture plates

All assays were using human embryonic kidney (HEK)-293 SL cells (a gift from Stephane Laporte). Cells were grown at 37 ➦C with 5% CO2 in DMEM with 4.5 g/L glucose, Lglutamine, and 10% newborn calf serum (NCS, Wisent BioProducts, Canada) and penicillinstreptomycin (PS, Wisent BioProducts, Canada). Two days prior to measurements, cells were transfected using polyethyleneimine (PEI, Polysciences Inc., Canada, No. 23966), with a ratio between PEI and DNA of 3:1. Afterwards, 20 000 cells per well were seeded into white Cellstar PS 96-well cell culture plates (Greiner Bio-One, Germany). On the day of the measurement, medium was removed and Tyrode's buffer (137 mM NaCl, 0.9 mM KCl, 1 mM MgCl 2 , 11.9 mM NaHCO 3 , 3.6 mM NaH 2 PO 4 , 25 mM Hepes, 5.5 mM glucose, 1 mM CaCl 2 , pH 7.4) was added, followed by incubation at 37 ➦C of at least 30 min. Ten minutes before measurement, adrenaline was added, with concentrations ranging from 31.6 nM to 3.16 mM in half-log steps, as well as a buffer control.