Am. J. Respir. Crit. Care Med., Vol 150, No. 3, Sep 1994, 724-728.
Capsaicin reduces ozone-induced airway inflammation in guinea pigs
T Kaneko, H Ikeda, L Fu, H Nishiyama, M Matsuoka, HO Yamakawa and T Okubo
First Department of Internal Medicine, Yokohama City University School of Medicine, Japan.
We investigated whether neural pathways are involved in mediating ozone
(O3)-induced airway inflammation. To determine this, we studied the
contribution of adrenergic and cholinergic pathways to the O3-induced
increase in airway vascular permeability, an indicator of airway
inflammation, by measuring vascular permeability after giving guinea pigs
propranolol or atropine to block these pathways. We also studied the
contribution to O3-induced airway inflammation of neuropeptides localized
in unmyelinated airway sensory nerves, by measuring vascular permeability
after giving capsaicin to deplete neuropeptides from these nerves. We found
that capsaicin reduced but did not abolish the increase in airway vascular
permeability induced by 3 ppm O3 for 30 min. Propranolol and atropine had
no effect on airway vascular permeability. These results indicate that
neuropeptides released from sensory nerves, presumably by acting through
the axon reflex, partly mediate O3-induced airway inflammation, and that
adrenergic and cholinergic pathways are not involved.
