<p>Concentration-response curves of forskolin-evoked cAMP accumulation in ventricular cardiomyocytes (A) and the inotropic response in ventricular strips (B) in the presence of the βAR blocker timolol (1 µM) in control or after PTX pre-treatment. Accumulation of cAMP was measured in the presence of IBMX, with basal cAMP accumulation (in pmol cAMP/mg protein): control: 38.8±5.3; PTX: 30.4±4.0. Basal force was (in mN/mm<sup>2</sup>): control: 4.05±0.56; PTX: 3.91±0.66. Data are mean ± SEM. *P<0.05, paired t-test (cAMP accumulation) or unpaired t-test (inotropic response).</p
