Figure 5. Inhibition of L-type Ca2+ current with Cd2+ (200 μm) allows the appearance of systolic [Ca2+] alternans.
Linescan data from a voltage clamped cell being stimulated to contract by a depolarising pulse of 36 mV from a holding potential of −40 mV, 4 consecutive stimuli are shown before and after inhibition of L-type Ca2+ current with Cd2+. The traces below show the mean fluorescence of a 20 pixel wide box at the level of the arrow expressed as F/Fo.