Comparison of electrophysiological properties of through the “atherosclerotic” and “normal” channels expressed in Xenopus oocytes with α ₂δ-1 subunit and the primary cardiac β _2a subunit and measured with 2.5 mM Ca²⁺ as the charge carrier. (a) Representative traces of evoked by 1 s step depolarizations to +20 mV from = −90 mV and normalized to the same amplitude. (b) Fractional recovery of from inactivation. (c) Averaged activation (/-) curves fit by the Boltzmann function. A 1 s test pulses in the range of −40 to +50 mV (10-mV increments) were applied from = −90 mV with 30-s intervals.