Bs. Zielinski et al., NITRIC-OXIDE SYNTHASE IN THE OLFACTORY MUCOSA OF THE LARVAL SEA LAMPREY (PETROMYZON-MARINUS), Journal of comparative neurology, 365(1), 1996, pp. 18-26
The use of nitric oxide, a product of enzymatic reduction of L-arginin
e by nitric oxide synthase, as a modulator of processes within the olf
actory mucosa was investigated in larval sea lampreys, extant fish of
ancient vertebrate origin. In the present study, we demonstrated that
the sea lamprey olfactory mucosa is specifically sensitive to L-argini
ne, that the L-arginine responses are inhibited by an inhibitor of nit
ric oxide synthase, Nw-nitro-L-arginine, and that nitric oxide synthas
e is present in olfactory receptor cells, sustentacular cells, and bas
al cells. Electron microscopic examination using NADPH-diaphorase hist
ochemistry revealed intense labeling within secretory vesicles of sust
entacular cells and in proximity to mitochondria within olfactory rece
ptor cell dendrites and sustentacular cells. At the base of the olfact
ory epithelium, NADPH-diaphorase staining was intense in the perinucle
ar cytoplasm of a subpopulation of basal cells, moderate in sustentacu
lar cell foot processes, and scattered in olfactory receptor cell axon
s. Throughout axons in the olfactory epithelium and the lamina propria
, labeling predominated in axonal profiles with mitochondria. These ph
ysiological and ultrastructural studies imply that in sea lamprey larv
ae, nitric oxide modulates peri-receptor events of L-arginine chemosti
mulation, olfactory receptor cell axonal activity, and developmental p
rocesses. (C) 1996 Wiley-Liss, Inc.