Figure 4.

Differential cardioprotective duration mediated by the adenosine A₁ and A₃ receptors. Cultured ventricular cells were prepared and exposed to either CCPA (10 nM) or Cl-IB-MECA (10 nM) for 5 min. Media were replaced with fresh media lacking the agonist. Cells were then incubated under normal O₂ for 10, 30, 45, or 60 min before being exposed to 90 min of simulated ischemia. The percentage of cells killed was determined after the 90-min ischemic period. Data represented the means and standard errors of five experiments. At the 30- and 45-min time points after the adenosine agonist exposure, the percentage of cells killed and the amount of creatine kinase released were significantly less in Cl-IB-MECA-treated than in CCPA-treated myocytes (t test, P < 0.01).