Abstract
Prenatal and postnatal development of neuronal NO synthase (nNOS) immunoreactivity and NADPH diaphorase (NADPHd) histochemical activity were studied in the rat kidney. NADPHd activity appeared at prenatal day 18, and nNOS immunoreactivity was first detected at prenatal day 19. However, these activities were rarely found before the prenatal day 20, and their staining intensity was very weak. Neuronal NOS protein and NADPHd activity appeared first in the inner layer of renal cortex. In higher magnification, they localized not only in macula densa cells but also in perimacular epithelial cells connected to the macula densa. With development, the number of nNOS immunoreactive and NADPHd positive sites increased dramatically and many nNOS-positive maculae densae were detected in the juxtamedullary region of the cortex at postnatal day 5. At postnatal day 14, the staining pattern of nNOS and NADPHd was similar to that of adults. NADPHd activity and nNOS immunoreactivity were found in very early stages of nephrogenesis including in prenatal days before full development of the glomerulus.
