Virus infection potentiates the increase in airway blood flow
produced by substance p.
Yamawaki, Isao, Pierangelo Geppetti, Claude Bertrand, Brendan Chan,.
Pierre Massion, Giovanni Piedimonte and Jay A. Nadel
APStracts 2:0130A, 1995.
We examined the effect of respiratory tract infection with Sendai
virus on responsiveness of airway blood flow to substance P (SP) in
rats. Pathogen-free rats were inoculated with either Sendai virus
suspension or sterile virus growth medium into each nostril. Five
days later, we measured airway and esophageal blood flow before and
immediately after injection of SP or histamine into the left
ventricle in rats of both groups, using a modification of the
reference-sample microsphere technique. Virus infection potentiated
the increase in airway blood flow evoked by SP but not by histamine.
We also examined the effect of neutral endopeptidase (NEP) and
angiotensin-converting enzyme (ACE) on SP-induced increase in airway
blood flow. Both phosphoramidon (NEP inhibitor) and captopril (ACE
inhibitor) potentiated the increase in airway blood flow produced by
SP in pathogen-free rats. In the presence of both peptidase
inhibitors a submaximal dose of SP increased blood flow to a similar
level in infected and pathogen-free rats. Thus, decreased activity of
both ACE and NEP may be involved in the exaggerated increase in
airway blood flow evoked by SP in virus-infected rats.
Received 30 November 1994; accepted in final form 13 March 1995.
APS Manuscript Number A1221-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 4 April 1995.