Heterogeneous NADH fluorescence during post-anoxic reactive hyperemia in saline perfused rat heart

In the present study epicardial NADH fluorescence photographs were taken of rat hearts during dynamic transitions of oxygen content of the myocardium. Hearts were perfused in a Langendorff set-up where it was possible to switch between low and high-pO2 perfusates. NADH fluorescence photographs were taken with a suitable fluorescence set-up and photo negatives digitized and analyzed by use of a computer. Restoration of perfusion with a high-pO2 solution resulted in a reactive hyperemic flow being established. Prior to the occlusion being lifted high NADH fluorescence was observed. Reactive hyperemic flow was associated with heterogenic NADH fluorescence patterns which diminished as control flow was restored. The patterns observed during reactive hyperemia were identical to those observed when tissue oxygen was restored by high-pO2 perfusion following high flow hypoxia achieved by low-pO2 perfusion. This study shows that heterogenic epicardial flow patterns are associated with reactive hyperemia.