Unknown

Human embryonic kidney 293 cells stably expressed human Kv1.1 channels were used for activity evaluation. Whole cell currents were measured with the voltage clamp method of the patch clamp technique using an EPC-9 amplifier. The currents were filtered at 1 kHz, and series resistance was actively compensated by at least 80%. A p/4 leak subtraction protocol was used in the study, with the exception of the experiments for frequency dependence. The patch electrodes were fabricated from borosilicate glass capillary tubes with filament using a Sutter P-97 puller. The pipettes had a resistance of 2–4 M and were filled with a solution containing the following electrolyte concentrations: 160 mM KCl, 0.5 mM MgCl2, 10 mM HEPES, and 2 mM Na2ATP, with a pH of 7.25 adjusted with KOH. The extracellular solution consisted of 135 mM NaCl, 5 mM KCl, 2 mM CaCl2, 2 mM MgCl2, 5 mM HEPES, 10 mM sucrose, and 0.01 mg/ml phenol red, with a pH of 7.4 adjusted with NaOH. All experiments were performed at room temperature. Dextroropivacaine was dissolved in the watery extracellular solution, yielding stock solutions of 1 mM and drug was applied on the cells by a perfusion system at concentrations 10mkM-1000mkM.