Direct contractile effect of endothelin-1 on isolated circular smooth muscle cells of guinea pig caecum.
Smooth muscle cells isolated from the circular muscle layers of the guinea pig caecum were used to determine whether endothelin-1 (ET-1) can cause contraction by exerting a direct action on smooth muscle cells. In addition, the inhibitory effects of 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8), an inhibitor of intracellular Ca2+ release, verapamil, a Ca2+ channel blocker, and removal of extracellular Ca2+ on the ET-1-induced muscle contraction were examined. ET-1 elicited a contractile response of isolated smooth muscle cells in a dose-dependent manner (ED50: 2 nM). TMB-8, verapamil, and removal of extracellular Ca2+ significantly inhibited the contraction produced by ET-1. These results strongly suggest that ET-1 has a direct contractile effect on circular smooth muscle cells of the guinea pig caecum, and that this contraction depends on both intracellular and extracellular Ca2+.
Okabe
H
H
Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Chijiiwa
Y
Y
Yoshinaga
M
M
Misawa
T
T
Kabemura
T
T
Nawata
H
H
D000818:Animals; D002118:Calcium / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002432:Cecum / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000494:pharmacology*; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D016232:Endothelins; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D014700:Verapamil; D002118:Calcium