Figure 2.

Engineered cardiac tissues (ECTs) respond to effectors of the cyclic adenosine monophosphate (cAMP) signaling pathway. A, Treatment with isoproterenol induced an increase in contractile force with EC₅₀ of 0.5 nM (n = 12). B, Like isoproterenol, dobutamine induced an increase in contractile force with EC₅₀ of 16 nM (n = 5). C, Milrinone, a phosphodiesterase-3 (PDE3) inhibitor also increased contractile force with EC₅₀ of 1.6 µM (n = 6). D, Treatment with pituitary adenylate cyclase-activating peptide (PACAP27) induced an increase in contractile force with EC₅₀ of 1.1 nM (n = 6). Data are presented as mean ± SEM.