Abstract 13513: Roles of Endothelium-Dependent Hyperpolarization in Pulmonary Microcirculation in Mice

Background: The endothelium modulates vascular tone by synthesizing and releasing endothelium-derived relaxing factors, including prostacycline (PGI2), nitric oxide (NO), and endothelium-dependent hyperpolarization (EDH). Although it is widely known that EDH plays an important role in systemic microcirculation, its role in pulmonary microcirculation remains largely unknown. Furthermore, although pulmonary hypertension (PH) is recognized as a progressive vasculopathy, the initiating mechanisms of the vasculopathy also remain to be elucidated. In this study, we thus aimed to elucidate the role of EDH in pulmonary microcirculation. Methods and Results: We performed experiments with isolated perfused mouse lungs. Isolated whole lungs were prepared from control mice and chronic hypoxic mice (10% O2 for 1, 2 and 28 days). We evaluated the contribution of PGI2, NO, and EDH in isolated lungs by the inhibitory effect of indomethacin (Indo, 10-5 mol/L), Nω-nitro-L-arginine (L-NNA, 10-4 mol/L), and apamin (Apa, 10-6...