Metabolism of anandamide in cerebral microvascular endothelial cells.
Anandamide (N-arachidonoylethanolamine, AEA), an endogenous cannabinoid receptor agonist, causes potent vasodilation in the cerebral circulation through an endothelial-dependent or -independent mechanism. We have investigated the processing of [3H]AEA in cultured mouse cerebral microvascular endothelial cells (MEC) in order to better understand its mechanism of action in the cerebral vasculature. These cells took up anandamide very quickly, reaching a maximum value in 5 min and remaining at that level for at least 8 h. Analysis of the cell lipids demonstrated that, in addition to free anandamide, radioactivity was incorporated into phosphatidylcholine (PC), phosphatidylinositol (PI), and phosphatidylethanolamine (PE) in a time-dependent manner. Analysis of the hydrolyzed cell lipids indicated that anandamide was converted to arachidonic acid, a process that was inhibited by the selective fatty acid amide hydrolase inhibitor oleyl trifluoromethyl ketone (OTMK). Phospholipase A2 (PLA2) hydrolysis of the PC, PI, and PE fractions indicated that the arachidonic acid formed from anandamide was esterified predominately into sn-2 position of the endothelial phospholipids. Furthermore, anandamide and arachidonic acid were released when the cells were incubated with A23187. These results suggest that the biological activity of anandamide might be regulated by its rapid uptake and calcium-dependent release in endothelial cells, and conversion of anandamide to arachidonic acid might serve as an inactivation process in the cerebral microcirculation.
Chen
Ping
P
Department of Biochemistry, University of Iowa College of Medicine, 4-403 BSB, Iowa City, IA 52242, USA.
Hu
Shanming
S
Harmon
Shawn D
SD
Moore
Steven A
SA
Spector
Arthur A
AA
Fang
Xiang
X
D000581:Amidohydrolases / Q000037:antagonists & inhibitors; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D001095:Arachidonic Acids / Q000378:metabolism* / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D063386:Cannabinoid Receptor Agonists; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism* / Q000494:pharmacology; D002196:Capillaries / Q000166:cytology / Q000378:metabolism*; D002531:Cerebellum / Q000098:blood supply / Q000378:metabolism*; D063388:Endocannabinoids; D004730:Endothelium, Vascular / Q000378:metabolism*; D007476:Ionophores / Q000494:pharmacology; D007659:Ketones / Q000494:pharmacology; D051379:Mice; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D010743:Phospholipids / Q000096:biosynthesis*; D053284:Polyunsaturated Alkamides; D043882:Receptors, Cannabinoid / Q000378:metabolism
D001095:Arachidonic Acids; D063386:Cannabinoid Receptor Agonists; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D007476:Ionophores; D007659:Ketones; D010743:Phospholipids; D053284:Polyunsaturated Alkamides; D043882:Receptors, Cannabinoid; D016718:Arachidonic Acid; D000001:Calcimycin; D010741:Phospholipases A; D054467:Phospholipases A2; D000581:Amidohydrolases; C078814:anandamide