Figure 8.
Effect of NS5806 on KV4.3/KChIP2/DPP6 co-expressed with KV1.4 channels. KV4.3/KChIP2/DPP6 and KV1.4 were co-expressed in Xenopus laevis oocytes in a 1:1 current ratio. Currents were elicited using the depicted voltage protocol and measured in the absence and in the presence of 10 µM NS5806. (A) Relation between peak current density and voltage, n= 8. (B) Single exponential equations were fitted to the current decays, and the time constants (τ) are shown as a function of voltage, n= 8. (C) Steady-state inactivation of KV4.3/KChIP2/DPP6/KV1.4 currents. Normalized tail current amplitudes are plotted as a function of the prepulse potential and Boltzmann equations are fitted to the data, n= 8. (D) Time-dependent recovery from inactivation. KV4.3/KChIP2/DPP6/KV1.4 currents were activated by a two-pulse protocol. Current amplitudes at the second test pulse were normalized to that of the first test pulse and plotted as a function of the inter-pulse interval and double-exponential equations were fitted to the data, n= 7. (E) Bar graph showing the time-constants of KV4.3/KChIP2/DPP6/KV1.4 recovery from inactivation, τ1 and τ2 as well as pre-exponential factors. *P < 0.05, **P < 0.01, ***P < 0.001; significantly different in the absence and presence of NS5806. DPP, dipeptidyl-peptidase; KChIP2, K channel interacting protein 2.