Repeated measurement of respiratory function and bronchoconstriction in unanesthetized mice.
A noninvasive forced oscillation technique was used to determine respiratory function in unanesthetized and spontaneously breathing mice. Pseudorandom 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 was calculated. Study of intra-animal variability on a short- and a long-term basis revealed that the real part of respiratory transfer impedance was reproducible within 9%. The imaginary part appeared less reproducible (within 22%). Furthermore, bronchoconstrictive responses were investigated and analyzed by evaluation of respiratory resistance as measured at 16 Hz (Rrs16). During the first 15 min after ovalbumin challenge in ovalbumin-sensitized mice, Rrs16 was significantly increased [49 +/- 7% (SE)]. Inhalation of methacholine in untreated mice induced an increase in Rrs16 of 75 +/- 16% (SE). In saline-challenged animals, no significant changes were observed. This method enables evaluation of long-term respiratory function in mice and appeared to be a sensitive measure for bronchoconstriction.
Hessel
E M
EM
Department of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands.
Zwart
A
A
Oostveen
E
E
Van Oosterhout
A J
AJ
Blyth
D I
DI
Nijkamp
F P
FP
D000280:Administration, Inhalation; D000818:Animals; D000830:Animals, Laboratory; D016084:Bronchoconstriction / Q000187:drug effects / Q000502:physiology*; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C / Q000502:physiology*; D010047:Ovalbumin / Q000494:pharmacology; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000662:veterinary*
D016210:Methacholine Chloride; D010047:Ovalbumin