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Updated: Oct 19, 2026

In vitro Measurements of Tracheal Constriction Using Mice
Published on: June 25, 2012
Substance P relaxes rat bronchial smooth muscle via epithelial prostanoid synthesis
M Bodelsson1, S Blomquist, K Caverius
1Department of Anaesthesia and Intensive Care, University Hospital, Lund, Sweden. Mikael.Bodelsson@anest.lu.se
Background:
Substance P is present in bronchial nerve fibres. The physiological actions of substance P are mediated via tachykinin NK(1) receptors. Immunochemical studies have demonstrated tachykinin NK(1) receptors in the rat airway epithelium.
Objective:
To elucidate how epithelial tachykinin NK(1) receptors affect smooth muscle response to substance P.
Methods:
Contractile response of isolated rat bronchial trunk with or without epithelium was recorded.
Results:
In intact segments precontracted by 5-hydroxytryptamine, relaxation was induced by substance P and the nitric oxide donor, sodium nitroprusside. Removal of the epithelium abolished relaxation induced by substance P but did not affect relaxation induced by sodium nitroprusside. The cyclo-oxygenase inhibitor, indomethacin, but not the nitric oxide synthase inhibitor, L-N(G)-monomethylarginine, reduced the relaxation in response to substance P.
Conclusions:
Epithelial tachykinin NK(1) receptors mediate substance-P-induced relaxation of rat bronchial smooth muscle via release of prostanoids but not nitric oxide.
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