Figure 6.

(A) Examples of intracellular (AP) and extracellular (FP) recordings from guinea pig (left) and rabbit (right) ventricular slices. Shown are superimposed tracings before (pre-drug control) and following nifedipine exposure (10 µM). (B) Concentration-dependence of effects of nifedipine on ΔAPD₉₀, ΔFPD₉₀ and ΔQTcV in the following preparations: rabbit Purkinje fibre and ventricular slices, guinea pig ventricular slices and papillary muscle (data from Hayashi et al., 2005) and conscious dog. Also depicted are concentration–response curves for inhibition of the hERG K⁺ current (dashed grey line) and the L-type Ca²⁺ current (solid grey line; from Uehara and Hume, 1985) and the range of therapeutically effective protein-unbound drug plasma concentrations in humans (orange area; data from Redfern et al., 2003). The decrease in diastolic blood pressure (BP) in conscious dogs is also shown.