Journal of Applied Physiology, Vol 73, Issue 4 1608-1613, Copyright © 1992 by American Physiological Society
Comparison of upper and lower airway responses of two sensitized rat strains to inhaled antigen
L. J. Xu, S. Sapienza, T. Du, S. Waserman and J. G. Martin
Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada.
The purpose of the study was to investigate the relationships between upper
airways responses and pulmonary responses of two strains of highly inbred
rats to inhaled antigen. To do this we measured the upper and lower airways
resistance for 60 min after challenge of Brown-Norway rats (BN; n = 13) and
an inbred rat strain (MF; n = 11), derived from Sprague-Dawley, with
aerosolized ovalbumin (OA). Rats were actively sensitized with OA (1 mg sc)
using Bordetella pertussis as an adjuvant. Two weeks later the animals were
anesthetized and challenged. Tracheal pressure, esophageal pressure, and
airflow were measured, from which total pulmonary resistance was
partitioned into upper airway and lower pulmonary resistance (RL). The peak
upper airway response to inhaled OA was similar in BN (1.89 +/- 0.66
cmH2O.ml-1.s; n = 7) and MF (2.85 +/- 0.68 cmH2O.ml-1.s; n = 6). The lower
airway response to OA challenge was substantially greater in BN, and RL
changed from 0.07 +/- 0.01 to 0.34 +/- 0.13 (n = 6; P < 0.05). The MF
did not have any significant increase in RL after challenge; the baseline
RL was 0.12 +/- 0.02 and only reached a peak value of 0.15 +/- 0.05 (n = 5;
P = NS). Lower airway responsiveness of BN (n = 10) to serotonin, an
important mediator early allergic airway responses, was similar to MF (n =
7).(ABSTRACT TRUNCATED AT 250 WORDS)
