[Primary studies of nitric oxide synthase in chicken cochlea]

Nitric oxide (NO) is a new messenger molecule. This study describes the localization of NO synthase (NOS) in the chicken cochlea by means of NADPH-daiphorase (NADPH-d) histochemical stain. The results showed that the nerve ending at the base of hair cells, nerve fibers and ganglion cells were positive for NADPH-d activity. Ganglion cells reacted more strongly than the surrounding nerve fibers. Enzyme activity is localized within the cytoplasm of the ganglion cells. The shape of these cells seems to be round or oval, and uniform in size. It was suggested that NOS in chicken cochlea was the neuronal NOS (nNOS). Also, NOS activity existed in the endothelium cells of the tegmentum vasculosum. These characteristics and the significance of study were discussed.