Fig. 4.

Induced expression of the S68E transgene enhances the in vivo contractility response to Iso. In vivo catheterization was performed in anesthetized mice (see methods), and the maximal first time derivatives of the left venticular (LV) pressure rise (+dP/dt) and fall (−dP/dt) and heart rate were continuously monitored, both at baseline and with increasing doses of Iso. The average maximal +dP/dt achieved with each dose of Iso in six noninduced mice (●) and eight induced mice (◇) is shown. Composite results are shown in Table 1. Two-way ANOVA indicated significant group (P < 0.0065) and Iso (P < 0.0001) effects. *P < 0.0065, noninduced vs. induced mice.