Possible Involvement of Nitric Oxide in the Suppression of the Release of Cellular ATP During Ischemia in Cultured Cardiac Myocytes

摘要

Nitric oxide (NO) plays various functional and pathological roles as an intracellular or intercellular messenger in the heart. In this study, we investigated whether NO produced during ischemia is crucially involved in the suppression of the ischemia-induced release of intracellular ATP. The concentration of extracellular ATP during ischemia was significantly increased by treatment of cultures with L-NMMA and the increase was reversed by co-treatment with SNAP, but not with decomposed SNAP, suggesting that NO suppressed the release of cellular ATP during ischemia. The L-NMMA-in-duced increase of extracellular ATP was also suppressed by treatment with blockers of connexin hemi-channels. The present results suggested that NO produced during ischemia suppressed the ischemia-induced release of intracellular ATP to the extracellular space via connexin hemichannels in cardiac myocytes.