[Distribution of nitric oxide synthase in human intracardiac ganglia]

This is the first study to report presence of nitric oxide synthase (NOS) in the human intracardiac nervous cells. By applying immunohistochemical technique it was shown that majority of neuronal perikaryons contain NOS 1 (neuronal NOS). We conclude that in human heart about half of neurons have NO-ergic phenotype. These cells are also cholinergic and related to parasympathetic part of autonomic nervous system. Moreover in human heart NOS contains pericellular baskets that surround intramural neurons. This points to the presence of the enzyme in parasympathetic preganglionic fibers. A substantial differences of patterns of NOS expression in cardiac neural ganglia between humans and experimental animals are discussed.