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.
Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma, Madrid, Spain.
J L
JL
Garcia
L
L
Monge
B
B
Gómez
G
G
Diéguez
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