Contractile effect of endothelin on isolated iris sphincter muscle of the pig.
Porcine endothelin (1 nM-0.3 microM) produced a concentration-dependent contraction of the isolated sphincter muscle of the pig iris. Neither atropine (1 microM) nor tetrodotoxin (1 microM) nor pre-exposure of the preparation to 10 microM capsaicin for 15 min affected the endothelin-induced response. We propose that the endothelin-induced contraction of the iris sphincter muscle of the pig is largely due to a direct action on smooth muscle cells and is unrelated to neurogenic myotic mechanisms.
Geppetti
P
P
Institute of Internal Medicine IV, University of Florence, Italy.
Patacchini
R
R
Meini
S
S
Manzini
S
S
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002211:Capsaicin / Q000494:pharmacology; D016232:Endothelins; D066298:In Vitro Techniques; D007498:Iris / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D010455:Peptides / Q000494:pharmacology*; D013552:Swine; D013779:Tetrodotoxin / Q000494:pharmacology
D016232:Endothelins; D010455:Peptides; D013779:Tetrodotoxin; D001285:Atropine; D002211:Capsaicin