Figure 4.

Effects of nifedipine and amlodipine on the L-type calcium current (I_Ca,L) and action potentials.(A) Typical I_Ca,L recordings in absence and presence of nifedipine (top) and amlodipine (bottom). Inset: voltage clamp protocol. (B) Average dose-response curves of nifedipine and amlodipine on I_Ca,L. Note that currents are normalized to current before drug application. Solid lines: Hill equation fits of average data. (C) Typical examples of APs in absence and presence of 150 nM nifedipine (top) and 50 nM amlodipine (bottom). Both drugs caused reversible AP-shortening. (D) Average effects of nifedipine (150 nM) and amlodipine (50 nM) on AP-properties. *P < 0.05 control conditions vs. drugs; ^#P < 0.05 nifedipine vs. amlodipine.