Reference : Endothelins: functional and autoradiographic studies in guinea pig trachea
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
Endothelins: functional and autoradiographic studies in guinea pig trachea
Tschirhart, Eric mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit >]
Drijfhout, J. W. [> >]
Pelton, J. T. [> >]
Miller, R. C. [> >]
Jones, C. R. [> >]
Journal of Pharmacology and Experimental Therapeutics
American Society for Pharmacology and Experimental Therapeutics
Yes (verified by ORBilu)
[en] Animals ; pharmacology ; metabolism ; Trachea ; Muscle, Smooth ; Muscle Contraction ; Male ; Guinea Pigs ; Glycopeptides ; Epithelium ; Endothelins ; Drug Interactions ; Binding Sites ; Autoradiography ; Anti-Bacterial Agents ; drug effects
[en] The presence of binding sites for [125I]endothelin-1 and the contractile activities of endothelins (ETs) and sarafotoxin S6b and the endothelin fragment ET(16-21) were investigated in guinea pig trachea. ETs and sarafotoxin S6b (0.1-100 nM) induced potent contractile responses in guinea pig trachea with EC50 values ranging from 1.57 to 12.97 nM. Epithelium removal increased the potencies of ET-1, ET-2 and S6b, but not that of ET-3, and maximal responses to ET-1 and ET-2 were also increased. Effects of epithelium removal were partially mimicked by phosphoramidon (10 microM), an enkephalinase inhibitor, suggesting that enkephalinase (EC. is able to degrade ET-1 and ET-2. ET-3-induced contractions were not affected by phosphoramidon. Autoradiographic studies suggested the presence of at least two specific binding sites for [125]ET-1 in guinea pig airway smooth muscle. The correlation between Kd and EC50 values suggests that the binding sites identified in the airway smooth muscle represent functional receptors for ETs. ET(16-21) and ET(16-21)-NH2 were less potent agonists than the ETs in guinea pig trachea and 10 microM ET(16-21) was unable to inhibit [125I]ET-1 binding in guinea pig airway smooth muscle. Therefore, these results suggest that the C-terminal hexapeptide of ET-1 cannot be used to classify ET receptors in guinea pig trachea.

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