FIGURE 6.

Baseline function of ex vivo toad and frog working hearts. A, at identical heart rates and normalized to heart weight, toad hearts exhibited a trend of smaller stroke volume than that of frog hearts. This difference was primarily due to the larger size of the toad heart normalized to body weights (Table 1), whereas the actual stoke volumes of toad and frog hearts were similar if normalized to the body weight. B, toad and frog hearts exhibited similar maximum aortic and ventricular pressures (AP and VP, respectively). C, toad hearts had faster systolic and diastolic contractile velocities (±dP/dt) than that of frog hearts. D, toad hearts had shorter ejection time than that of frog hearts. n = 3 in frog and n = 4 in toad groups. Values are presented as mean ± S.E. *, p < 0.05 versus frog heart in two-tail Student's t test.