Chronic exposure of young guinea pigs to sidestream tobacco smoke
enhances lung rapidly adapting receptor responsiveness to substance
p.
Bonham, A. C., K. S. Kott, and J. P. Joad.
Departments of Internal Medicine and Pharmacology and Pediatrics,
University of California, Davis, Davis, CA 95616
APStracts 3:0278A, 1996.
We determined the effect of sidestream tobacco smoke (SS) exposure on
responses of lung rapidly adapting receptors (RARs), peak tracheal
pressure (TP), and arterial blood pressure (ABP) to substance P in
young guinea pigs. Guinea pigs were exposed to SS or filtered air
(FA) from day 8 to day 41 - 45 of life. They were then anesthetized
and given 3 doses of i.v. substance P (1.56 - 4.94 nmol/kg). SS
exposure augmented substance P-evoked increases in RAR activity (P =
0.029, ANOVA), but not substance P-evoked increases in peak TP or
decreases in ABP. NK1 receptor blockade (CP 96,345, 400 nmol/kg)
attenuated substance P-evoked increases in RAR activity (P = 0.001)
and ABP (P = 0.009) but not in peak TP (P = 0.06). Thus, chronic
exposure to SS in young guinea pigs exaggerates RAR responsiveness to
substance P. The findings may help explain the increased incidence of
airway hyperresponsiveness and cough in children chronically exposed
to environmental tobacco smoke.
Received 29 March 1996; accepted in final form 10 June 1996.
APS Manuscript Number A310-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 June 96