Epithelium-dependent relaxation of guinea-pig tracheal smooth muscle by carbachol.
Modulation of the effect of carbachol by epithelium on tracheal smooth muscle of guinea-pig was studied by using coaxial bioassay system. The contractile response of the bioassay organ (epithelium-free tracheal smooth muscle of guinea-pig) to carbachol was well maintained along the observation period of 30 min. When the same bioassay organ was taken into epithelium-intact tracheal tube of guinea-pig, a significant relaxation followed the carbachol-induced initial contraction within 30 min which was abolished by the removal of epithelial cell layer. Epithelium-dependent relaxation with carbachol is not due to stimulation of M1-muscarinic receptors. The results indicate that airway epithelium has a role in the termination of carbachol-induced bronchoconstriction.
Guc
M O
MO
Hacettepe University, Faculty of Medicine, Department of Pharmacology, Ankara, Turkey.
Ilhan
M
M
Kayaalp
S O
SO
D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D004848:Epithelium / Q000502:physiology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D010890:Pirenzepine / Q000494:pharmacology; D013997:Time Factors; D014132:Trachea / Q000187:drug effects
D010890:Pirenzepine; D002217:Carbachol