AJP - Lung Cellular and Molecular Physiology, Vol 267, Issue 6 704-L711, Copyright © 1994 by American Physiological Society
Immunohistochemical demonstration of a paracrine role of nitric oxide in bronchial function
A. Rengasamy, C. Xue and R. A. Johns
Department of Anesthesiology, University of Virginia Health Sciences Center, Charlottesville 22908.
We addressed the controversial role of nitric oxide (NO) in bronchial
function by an immunohistochemical study of the localization of NO synthase
(NOS) and its effector protein, soluble guanylate cyclase, in rat bronchus.
For this study, a monoclonal antibody to the bovine constitutive neuronal
NOS was developed and characterized. In Western blot analysis, this
monoclonal antibody (anti-NOS antibody) reacted with bovine cerebellum NOS
(150 kDa) as well as with structurally different NOSs from cultured bovine
aortic endothelial cells (130 kDa) and cultured RAW 264.7 macrophages (130
kDa). The reactivity of anti-NOS antibody was confirmed by
immunohistochemical staining of rat cerebellum, arterial endothelial cells,
and cultured stimulated macrophages. When the distribution of NOS in rat
airway was characterized, the anti-NOS antibody showed immunoreactivity
within respiratory epithelium but not in the bronchial smooth muscle. The
NADPH-diaphorase staining correlated with the immunostaining. In contrast,
a monoclonal antibody to the rat lung-soluble guanylate cyclase
immunostained respiratory smooth muscle but not epithelium. This study
suggests a paracrine role for NO in bronchial function analogous to the
function of the NOS-soluble guanylate cyclase pathway in blood vessels.
