Figure 2.

Perfusing intact cardiomyocytes with 100 nM IpTxa produced an increase in the amplitude of the [Ca²⁺]_i transient followed by a gradual decrease to a new steady-state. Line-scan image (top) and associated fluorescence plot (bottom) of a field-stimulated mouse ventricular cardiomyocyte loaded with the Ca²⁺ indicator Fluo-4 and perfused constantly with normal Tyrodes solution in the absence of IpTxa. At the time indicated by the arrow, IpTxa (100 nM) or caffeine (10 mM) was perfused onto the cell. The protocol was repeated 36 times and the result below is representative of 12 experiments.