Fig. 2. Effect of remifentanil preconditioning on infarct size, as a percentage of the area at risk (IS/AAR), concentration dependently. IS/AAR in rat hearts subjected to remifentanil 0 (control), 1, 5, and 10 ng/ml. Values are presented as mean ± SD. * P < 0.05, ** P < 0.01 versus concentration 0 (control).