Figure 3.

Perfusing 3 µM IpTxa increased diastolic [Ca]_i and produced irregular [Ca²⁺]_i transients. 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 (3 μM) or caffeine (10 mM) was perfused onto the cell. The protocol was repeated 36 times and the result below is representative of three experiments.