Repeated measurement of respiratory function and bronchoconstriction in unanaesthetized mice. Hessel, E. M., A. Zwart, E. Oostveen, A. J. M. Van Oosterhout, D. I. Blyth, F. P. Nijkamp. Department of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands, TNO Toxicology and Nutrition Institute, Zeist, The Netherlands, Department of Pulmonology, Hospital 'Medisch Spectrum Twente', Enschede, The Netherlands, Respiratory Biology Group, Department of Cellular Science, Glaxo Research Ltd., Greenford, Middlesex, United Kingdom.
APStracts 2:0272A, 1995.
Respiratory function was determined in unanaesthetized and spontaneously breathing mice using a non-invasive forced oscillation technique. Pseudo-random noise pressure variations in a frequency range of 16-208 Hz were applied to the body surface, and the flow response was measured at the nose. From the pressure-flow relationship respiratory transfer impedance (Ztr) was calculated. Study of intra -animal variability on short and on long term basis revealed that the real part of Ztr was reproducible within 9%. The imaginary part appeared less reproducible (within 22%). Furthermore, bronchoconstrictive responses were investigated and analyzed by evaluating respiratory resistance as measured at 16 Hz (Rrs 16 ). During the first 15 min after ovalbumin challenge in ovalbumin -sensitized mice Rrs 16 was significantly increased (49% +/- 7% (SE)). Inhalation of methacholine in untreated mice induced an increase in Rrs 16 of 75% ? +/- ? 16% (SE). In saline-challenged animals no significant changes were observed. The method described in this paper enables evaluation of long term respiratory function in mice and appeared to be a sensitive measure for bronchoconstriction. 

Received 26 September 1994; accepted in final form 20 June 1995.
APS Manuscript Number A995-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on  6 July 1995.