Response of canine cerebral arteries to endothelin-1.
The effects of endothelin-1 (10(-10)-10(-7) M) were isometrically recorded in 4 mm cylindrical segments from the middle cerebral artery of dogs. Cumulative application of endothelin-1 produced marked, sustained contraction of arteries in a concentration-dependent-manner, the maximal response being about 2.6 times higher than that achieved with KCl (50 mM). The contraction by endothelin-1 was unaffected either by endothelium removal or by the cyclo-oxygenase inhibitors indomethacin (10(-6) M) and meclofenamate (10(-6) M). In a Ca(2+)-low (25 microM) solution the endothelin-1-induced arterial contraction was decreased. Therefore, the cerebral vasoconstriction induced by endothelin-1 could be caused by activation of specific receptors located on smooth muscle cells which would lead to the influx of extracellular calcium and vascular musculature contraction.
Garcia
J L
JL
Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma, Madrid, Spain.
Monge
L
L
Gómez
B
B
Diéguez
G
G
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002536:Cerebral Arteries / Q000187:drug effects; D004285:Dogs; D016232:Endothelins / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology; D011453:Prostaglandins / Q000494:pharmacology
D016232:Endothelins; D011453:Prostaglandins; D011189:Potassium Chloride; D002118:Calcium