Endothelial Nitric Oxide Synthase Plays an Obligatory Role in the Late Phase of Ischemic Preconditioning by Activating the Protein Kinase Cε–p44/42 Mitogen-Activated Protein Kinase–pSer-Signal Transducers and Activators of Transcription1/3 Pathway

Abstract

In contrast to previous reports, we found that basal eNOS activity does not modulate infarct size in the nonpreconditioned state. However, eNOS is obligatorily required for the development of the cardioprotective effects of late PC and acts as the trigger of this process by activating the PKC epsilon-MEK-1/2-p44/42 mitogen-activated protein kinase pathway, leading to Ser-727 phosphorylation of STAT1 and STAT3 and consequent upregulation of STAT-dependent genes such as cyclooxygenase-2. The effects of eNOS-derived NO are reproduced by exogenous NO (NO donors), implying that nitrates can upregulate cardiac cyclooxygenase-2.