Endothelin-1 and endothelin-3 relax isolated guinea pig trachea through different mechanisms.
The effects of endothelin-1 (ET-1) and endothelin-3 (ET-3) were investigated on carbachol-contracted guinea-pig trachea. ET-1 and ET-3 induced a dose-dependent relaxation of the precontracted preparations. ET-1-induced relaxation was attenuated by hemoglobin and methylene blue. By contrast, ET-3-induced relaxation was not affected by hemoglobin or methylene blue. The large conductance Ca(2+)-activated K(+)-channel blocker charybdotoxin antagonized ET-1- and ET-3-induced relaxations. These results show that charybdotoxin-sensitive K+ channels are involved in both ET-1 and ET-3 relaxant activities, whereas the nitric oxide pathway is involved only in ET-1 relaxant effects.
Hadj-Kaddour
K
K
Laboratoire de Pharmacodynamie, Faculté de Pharmacie, Montpellier, France.
Michel
A
A
Chevillard
C
C
D000818:Animals; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009126:Muscle Relaxation / Q000187:drug effects; D014132:Trachea / Q000187:drug effects* / Q000502:physiology
D016232:Endothelins