Lipoxygenase and calcium entry in vascular smooth muscle.
In the canine saphenous vein, inhibitors of cyclo-oxygenase augment contractile responses to acetylcholine, potassium chloride and partial alpha-adrenergic activation. This augmentation is prevented by inhibitors of lipoxygenase, and abolished by calcium entry blockers. These observations suggest that when Ca2+ enters the smooth muscle cells it activates the metabolism of arachidonic acid. If cyclo-oxygenase is inhibited, end-products of lipoxygenase exert a positive feedback on calcium entry. A similar mechanism may explain the hypoxic contractions observed in various blood vessels, including coronary arteries.
P M
PM
Vanhoutte
T J
TJ
Rimele
N A
NA
Flavahan
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002396:Catechols / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors; D004285:Dogs; D004837:Epinephrine / Q000494:pharmacology; D000860:Hypoxia / Q000503:physiopathology; D007213:Indomethacin / Q000494:pharmacology; D016859:Lipoxygenase Inhibitors; D009637:Masoprocol; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D011188:Potassium / Q000494:pharmacology
D001095:Arachidonic Acids; D002121:Calcium Channel Blockers; D002396:Catechols; D016861:Cyclooxygenase Inhibitors; D016859:Lipoxygenase Inhibitors; D016718:Arachidonic Acid; D009637:Masoprocol; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium; D007213:Indomethacin; D004837:Epinephrine