Endothelium-derived 2-arachidonylglycerol: An intermediate in vasodilatory eicosanoid release in bovine coronary arteries

Kathryn M. Gauthier, David V. Baewer, Sarah Hittner, Cecilia J. Billard, Kasem Nithipatikom, D. Sudarshan Reddy, J. R. Falck, William B. Campbell

Research output: Contribution to journalArticlepeer-review

60 Scopus citations

Abstract

Acetylcholine stimulates the release of endothelium-derived arachidonic acid (AA) metabolites including prostacyclin and epoxyeicosatrienoic acids (EETs), which relax coronary arteries. However, mechanisms of endothelial cell (EC) AA activation remain undefined. We propose that 2-arachidonylglycerol (2-AG) plays an important role in this pathway. An AA metabolite isolated from bovine coronary ECs was identified as 2-AG by mass spectrometry. In ECs pretreated with the fatty acid amidohydrolase inhibitor diazomethylarachidonyl ketone (DAK; 20 μmol/l), methacholine (10 μmol/l)-stimulated 2-AG release was blocked by the phospholipase C inhibitor U-73122 (10 μmol/l) or the diacylglycerol lipase inhibitor RHC-80267 (40 μmol/l). In U-46619-preconstricted bovine coronary arterial rings, 2-AG relaxations averaging 100% at 10 μmol/l were inhibited by endothelium removal, by DAK, by the hydrolase inhibitor methyl arachidonylfluorophosphate (10 μmol/l), by the cyclooxygenase inhibitor indomethacin (10 μmol/l), but not by the CB1 cannabinoid receptor antagonist SR-141716 (1 μmol/l). The cytochrome P-450 inhibitor SKF-525a (10 μmol/l) and the 14,15-epoxyeicosa-5Z-enoic acid EET antagonist (14,15-EEZE; 10 μmol/l) further attenuated the indomethacin-resislant relaxations. The nonhydrolyzable 2-AG analogs noladin ether, 2-AG amide, and 14,15-EET glycerol amide did not induce relaxation. N-nitro-L-arginine-resistant relaxations to methacholine were also inhibited by U-73122, RHC-80267, and DAK. 14,15-EET glycerol ester increased opening of large-conductance K+ channels 12-fold in cell-attached patches of isolated smooth muscle cells and induced relaxations averaging 95%. These results suggest that methacholine stimulates EC 2-AG production through phospholipase C and diacylglycerol lipase activation. 2-AG is further hydrolyzed to AA, which is metabolized to vasoactive eicosanoids. These studies reveal a role for 2-AG in EC AA release and the regulation of coronary tone.

Original languageEnglish (US)
Pages (from-to)H1344-H1351
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume288
Issue number3 57-3
DOIs
StatePublished - Mar 2005

Keywords

  • Arachidonic acid
  • Endothelium-derived hyperpolarizing factor
  • Epoxyeicosatrienoic acids
  • Prostacyclin
  • Vascular relaxation

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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