Figure 1.

NS5806 modulation of I _to from rabbit ventricular cells. (A) Representative current records in control, after application of 10 μmol/L NS5806 and after washout with control solution. The voltage protocol is shown as an inset. (B) Mean (± SEM, n = 26) time course of response to 10 μmol/L NS5806 of I_to (measured as peak minus end‐pulse current), using protocol shown in A. (C) Representative current records in control, after application of 100 μmol/L NS5806 and after washout with control solution. The voltage protocol is the same as that used for panel A. (D) Mean (± SEM, n = 10) time course of response of I_to (peak minus end‐pulse current) to 100 μmol/L NS5806, using protocol shown in A. Note the initial stimulation followed by inhibition. (E) Concentration‐dependence of the maximal agonist effect of NS5806 on I_to. Data (for peak minus end‐pulse current effects) were fitted with a standard Hill‐equation to get the EC ₅₀ and n_H values given in the ‘Results’ text. Values in parentheses denote number of independent replicates at each concentration. (F) Concentration–response relation for the steady‐state effect of NS5806 on I_to. For each cell, the effect of NS5806 at 120 sec was recorded and current amplitude expressed as a % of control. Data (for peak minus end‐pulse current effects) were fitted with a two site (agonist and antagonist) Hill‐equation to get the EC ₅₀/IC ₅₀ and n_H values. Values in parentheses denote number of independent replicates at each concentration.