NADPH-DIAPHORASE Staining was studied in the intact olfactory system a
nd following transections of the olfactory nerve. Intense staining was
found in the olfactory epithelia of rat and salamander, especially at
the mucosal surface. The olfactory bulb nerve and glomerular layers w
ere also stained. Transection of the olfactory nerve in salamander, or
bulbectomy in rat, resulted in decreased staining at the mucosal surf
ace, although staining increased in cells deeper in the epithelium. De
afferentation also caused the disappearance of staining in the olfacto
ry nerve and glomerular layers of the bulb. These results support the
notion of a role for NADPH in the olfactory system, perhaps as a biosy
nthesis substrate for NO modulation of cGMP in the developing epitheli
um and a complementary role for CO in the adult.