Yoshihiko Chiba*, Yuka Takada, Hiroyasu Sakai, Hisao Takeyama and Miwa
Misawa
Department of Pharmacology, School of Pharmacy, Hoshi University, 2-4-41
Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
*Corresponding author.ﾊFAX:+81-3-5498-5787
E-mail: chiba@hoshi.ac.jp/
Abstract: Smooth muscle responsiveness of intrapulmonary small bronchi
obtained from repeatedly antigen-challenged rats was compared with that
from control animals to determine whether smooth muscle contractility of
peripheral airways is augmented by such repeated challenge. In intact (non-permeabilized)
smooth muscles of intrapulmonary bronchi, the acetylcholine (ACh)-induced
contractile response was significantly augmented in the repeated challenge
group, although 60-mM K+-induced contraction was within the normal
level. In b-escin-permeabilized muscles, no significant
difference between groups was observed in the Ca2+-induced contractile
responses. Thus, augmented ACh-induced contraction of intact intrapulmonary
small bronchial smooth muscle might be, at least in part, due to an enhanced
ACh-mediated Ca2+-sensitizing signal.
Keywords: Airway hyperresponsiveness, Permeabilized intrapulmonary bronchial
smooth muscle,
Ca2+ sensitization
Copyrightｩ The Japanese Pharmacological Society 2000
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