Nitric oxide synthase expression and function in embryonic and adult cardiomyocytes

Nitric oxide (NO) is an important signalling molecule that plays a relevant role in different cell systems, among them the adult heart. The effects of NO are primarily mediated through modulation of Ca2+ homeostasis, myofibri llar contractility, and metabolic regulation in cardiomyocytes. Recent evid ence also suggests an important role of NO for cardiomyogenesis by modulati ng proliferation and differentiation and regulating cardiac function. In th e embryonic, but also the healthy and diseased, adult mammalian heart, the inducible (iNOS) and the endothelial (eNOS) nitric oxide synthases (NOS) ar e detected. However, the expression pattern of NO and its function differ d uring development. Furthermore, under pathophysiological conditions NOS exp ression can also change and cause impairment of cardiac performance and cyt otoxic effects. The present review focuses on the role and function of NO d uring cardiomyogenesis, the mechanisms responsible for eNOS availability, a nd the paracrine effects of NO generated by cardiomyocytes. (C) 2001 Wiley- Liss, Inc.