We examined the variation in plasma levels of endothelin (ET), calcitonin gene-related peptide (CGRP), nitric oxide (NO), and malondialdehyde (MDA), as well as superoxide dismutase (SOD) activity, in acute myocardial ischemia reperfusion injury in a rabbit model. Seventy rabbits were randomly assigned into 3 groups. Open-chest surgery (OCS) was performed for all rabbits. Group A (N = 20) received sham-surgery, group B (N = 25) was the reperfusion group, and group C (N = 25) was the infarction group. At 12 h after chest closure, plasma ET levels in groups B and C were clearly increased, while CGRP levels were clearly decreased, particularly in group B. At 24 h after chest closure, ET levels were higher than before OCS, while there was no significant difference between groups B and C. ET in group B was decreased, while that in group C was increased at 12 h. No significant difference in CGRP was observed between 12 and 24 h after chest closure. NO levels in groups B and C at 12 h after chest closure were significantly decreased compared to those before OCS. NO levels in group B at 24, 48, and 72 h were significantly lower than those at 12 h, while those of group C were not significantly changed after 12 h. Dynamic monitoring and comparison of plasma levels of ET, CGRP, NO, and MDA as well as SOD activity revealed that appropriate intervention of these factors may reduce reperfusion injury.