Endothelium-dependent contractions to calcium ionophore A23187, arachidonic acid, and acetylcholine in canine basilar arteries

• Published in: Stroke (1970) Vol. 19; no. 4; pp. 476 - 479
• Main Authors: KATUSIC, Z. S, SHEPHERD, J. T, VANHOUTTE, P. M
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01-04-1988
• Subjects: Acetylcholine - pharmacology; Animals; Arachidonic Acid; Arachidonic Acids - pharmacology; Basilar Artery - drug effects; Biological and medical sciences; Calcimycin - pharmacology; Cardiovascular system; Dogs; Endothelium, Vascular - physiology; Imidazoles - pharmacology; Indomethacin - pharmacology; Medical sciences; Miscellaneous; Pharmacology. Drug treatments; Vasoconstriction; Fissipedia; Carnivora; Basilar artery; Arachidonic acid; Muscle contraction; Endothelium; Isolated organ; Vertebrata; Mammalia; Animal; Acetylcholine; Ionophore; Dog
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/01.STR.19.4.476

The effects of the calcium ionophore A23187, arachidonic acid, and acetylcholine were studied in isolated canine basilar arteries. Rings with and without endothelium were suspended for isometric tension recording in physiological saline. In unstimulated rings, A23187, arachidonic acid, and acetylcholine caused endothelium-dependent contractions. The contractions of rings caused by uridine 5'-triphosphate were not affected by removal of the endothelium. An inhibitor of cyclooxygenase, indomethacin (10(-5) M), prevented excitatory responses to A23187, arachidonic acid, and acetylcholine but did not alter contractions caused by KCl. An inhibitor of thromboxane synthetase, dazoxiben (10(-4) M), significantly reduced endothelium-dependent contractions to A23187 and arachidonic acid but did not significantly affect contractions caused by acetylcholine. These results demonstrate that A23187, arachidonic acid, and acetylcholine cause excitatory endothelium-dependent responses in canine cerebral blood vessels by increasing the release of product(s) of cyclooxygenase from endothelial cells; in the case of A23187 and arachidonic acid, thromboxane A2 contributes to the endothelium-dependent contractions.