Figure 4.

In vivo determination of left ventricular contractility in β₁TG4 and wild-type mice. Left ventricular pressures in anaesthetized mice were measured with a Millar 1.8 French catheter. (A) Left ventricular maximal contractility (dp/dt_max) was measured at different ages in wild-type (▫) and β₁TG4 (●) mice. Data are from four mice for each age group. The Inset shows an original pressure tracing. (B) Effects of β-adrenergic receptor blockade by 1.5 μg of propranolol per g of body weight on dp/dt_max in wild-type and β₁TG4 transgenic animals at 16 weeks of age. mmHg, millimeters of mercury.