An epithelial-dependent contracting factor induced by calcium influx in guinea-pig trachea.
The effects of epithelium removal were studied on the contraction induced by Ca2+ in K(+)-depolarizing solution, and by the calcium ionophore A 23187 in guinea-pig isolated tracheal strips. Epithelium removal reduced the maximal response to Ca2+ in K(+)-depolarizing solution and caused a significant shift to the right of the Ca2+ concentration-response curves. The contraction induced by the calcium ionophore A 23187 (10(-6) M) was also markedly reduced by epithelium removal. These results suggest the occurrence of an epithelium-derived contracting factor. The effects of hexamethonium, atropine, spantide and thiorphan showed that acetylcholine and neurokinins play a minor role in the Ca(2+)-induced contraction. The epithelium-dependent potentiation of the calcium- and of the A 23187-induced contractions was inhibited by an antibody selective for rat calcitonin gene-related peptide (rCGRP alpha). Therefore, CGRP-like immunoreactive material may be part of the epithelium-dependent contracting factor of guinea-pig trachea. Comparison of concentration-response curves for rCGRP alpha in epithelium-free and in intact guinea-pig tracheal strips suggests that an epithelium-dependent contracting factor may be mobilized by CGRP.
Bertrand
C
C
Neuroimmunopharmacologie, INSERM CJF 91-05, Faculté de Pharmacie, Université Louis Pasteur--Strasbourg, France.
Da Silva
A
A
Landry
Y
Y
Theodorsson
E
E
Tschirhart
E
E
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D004848:Epithelium / Q000502:physiology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D015288:Neurokinin A / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects / Q000502:physiology*
D000001:Calcimycin; D013779:Tetrodotoxin; D015288:Neurokinin A; D015740:Calcitonin Gene-Related Peptide; D002122:Calcium Chloride; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium