Airway Responsiveness to Acetylcholine in Congenitally Bronchial-Hypersensitive (BHS) and Bronchial-Hyposensitive (BHR) Guinea Pigs in Vivo and in Vitro

Yukihiro YAGI; Masayoshi KUWAHARA; Masashi MAEDA; Hiromi KADOTA; Shizue SAEGUSA; Jun-ichi BIRUMACHI; Shigeru SUGANO; Ryoji NISHIBATA; Hiroki MIKAMI; Hirokazu TSUBONE

doi:10.1538/expanim.47.173

Original

Airway Responsiveness to Acetylcholine in Congenitally Bronchial-Hypersensitive (BHS) and Bronchial-Hyposensitive (BHR) Guinea Pigs in Vivo and in Vitro

Yukihiro YAGI, Masayoshi KUWAHARA, Masashi MAEDA, Hiromi KADOTA, Shizue SAEGUSA, Jun-ichi BIRUMACHI, Shigeru SUGANO, Ryoji NISHIBATA, Hiroki MIKAMI, Hirokazu TSUBONE

Author information

Yukihiro YAGI
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo
Masayoshi KUWAHARA
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo
Masashi MAEDA
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo
Hiromi KADOTA
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo
Shizue SAEGUSA
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo
Jun-ichi BIRUMACHI
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo
Shigeru SUGANO
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo
Ryoji NISHIBATA
Institute of Bio-Active Science, Nippon Zoki Pharmaceutical
Hiroki MIKAMI
Institute of Bio-Active Science, Nippon Zoki Pharmaceutical
Hirokazu TSUBONE
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo

Keywords: acetylcholine, acethylcholinesterase, airway smooth muscle, carbachol, muscarinic receptor

JOURNAL FREE ACCESS

1998 Volume 47 Issue 3 Pages 173-181

DOI https://doi.org/10.1538/expanim.47.173

Details

Abstract

The characteristics of airway responsiveness to acetylcholine (ACh) in congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs were clarified in vivo and in vitro. We measured the change in ventilatory mechanics in response to ACh inhalation by means of the bodyplethysmograph and the contractile responses of isolated trachea to ACh and carbachol (CCh). Further, muscarinic receptor subtypes involved these responses were identified. The basal values for ventilatory mechanics in BHS were not significantly different from those in BHR. Respiratory resistance to ACh was progressively increased in a time- and dose-dependent manner in BHS. The contractile responses of tracheal smooth muscle to ACh in BHS were significantly greater than those in BHR, but CCh-induced responses in BHS and BHR were similar. ACh- and CCh-induced contractions were mediated via M₃ receptors. These results suggested that the falling-down of BHS in response to ACh inhalation was caused by the strong constriction of the airway and the reduction in ventilation. Moreover, the airway hyperresponsiveness to ACh in BHS might be partly dependent on the change in acetylcholinesterase activity.

Corresponding author

Register with J-STAGE for free!