AJP - Lung Cellular and Molecular Physiology, Vol 268, Issue 4 584-L588, Copyright © 1995 by American Physiological Society
Immunochemical localization of type I VIP receptor and NK-1-type substance P receptor in rat lung
S. Ichikawa, S. P. Sreedharan, R. L. Owen and E. J. Goetzl
Department of Anatomy, Tokyo Medical College, Japan.
Peptidergic nerves in the respiratory tract release vasoactive intestinal
peptide (VIP) and substance P (SP), which mediate physiological and immune
functions. Antipeptide antibodies to type I VIP receptor (VIPR) and
NK-1-type SP receptor (SPR) were used to identify these receptors in normal
rat lungs. VIPRs and SPRs were detected on airway epithelium from the
trachea to the respiratory bronchioles but not in alveoli, submucosal
glands, or pulmonary smooth muscle, except for that of some pulmonary
veins. VIPRs also were expressed on macrophages around capillaries, in
tracheal and bronchial connective tissue, in alveolar walls, and in the
subintima of pulmonary veins and some arterioles. The absence of receptors
from airway smooth muscle and submucosal glands implies that mediation of
some known effects of SP and VIP may be epithelial or macrophage dependent.
Other types of VIPRs and SPRs on airway glands and smooth muscle may
transduce direct effects. The similar localization of VIPRs and SPRs in rat
lung suggests that VIP and SP may coordinately regulate some pulmonary
functions.
