Acetylcholine-Induced Smooth Muscle Contraction of Intrapulmonary Small Bronchi Is Augmented in Antigen-Induced Airway Hyperresponsive Rats
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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<SUP>+</SUP>−induced contraction was within the normal level.In β−escin−permeabilized muscles, no significant difference between groups was observed in the Ca<SUP>2+</SUP>−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 Ca<SUP>2+</SUP>−sensitizing signal.
- The Japanese Journal of Pharmacology
The Japanese Journal of Pharmacology 84(2), 221-224, 2000-10-01
The Japanese Pharmacological Society