Figure 2
From: Intracellular hemin is a potent inhibitor of the voltage-gated potassium channel Kv10.1
Voltage dependence of hemin-induced Kv10.1 inhibition. (A, left) Superposition of current traces recorded from inside-out patches according to the indicated pulse protocol in which depolarizations ranged from − 110 to 120 mV in 10-mV increments and 5-s interval before (black) and after (red) application of 10 nM hemin. Holding voltage: − 80 mV. (A, right) Current traces from the experiment shown on the left for the indicated voltages before (black) and after (red) hemin application. The gray traces are scaled hemin traces to match the maximal control current. Scale factors applied: 100 mV: 3.92; 40 mV: 5.2; − 40 mV: 10.7. (B) Mean current measured at the end of test depolarizations as a function of voltage with superimposed data fits according to Eq. (1). (C) Tail currents at − 140 mV as a function of test voltage with superimposed Boltzmann fits (Eq. 2). The dashed lines indicate the current normalized to the maximal current obtained in the fits (right axis). (D) Voltage dependence of relative current remaining after application of 10 nM hemin determined from test currents (B) (circles) and tail currents (C) (squares). (E) Parameters describing the voltage dependence of channel activation according to Eq. (1) without (−) and with 10 nM hemin (+); data are mean ± sem (n = 6). Solution: Standard K-Asp.
