|
|
||||||||
Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
It has been reported that the endogenous
cannabinoid N-arachidonylethanolamide
(AEA), commonly referred to as anandamide, has the characteristics of
an endothelium-derived hyperpolarizing factor in rat mesenteric artery.
We have carried out studies to determine whether AEA affects coronary
vascular tone. The vasorelaxant effects of AEA were determined in
isolated bovine coronary artery rings precontracted with U-46619 (3 × 10
9 M). AEA
decreased isometric tension, producing a maximal relaxation of 51 ± 9% at a concentration of
10
5 M. Endothelium-denuded
coronary arteries were not significantly affected by AEA. The CB1
receptor antagonist SR-141716A
(10
6 M) failed to reduce
the vasodilatory effects of AEA, suggesting that the CB1 receptor is
not involved in this action of AEA. Because AEA is rapidly converted to
arachidonic acid and ethanolamine in brain and liver by a fatty acid
amide hydrolase (FAAH), we hypothesized that the vasodilatory effect of
AEA results from its hydrolysis to arachidonic acid followed by
enzymatic conversion to vasodilatory eicosanoids. In support of this
hypothesis, bovine coronary arteries incubated with
[3H]AEA for 30 min
hydrolyzed 15% of added substrate; ~9% of the radiolabeled product
was free arachidonic acid, and 6% comigrated with the prostaglandins
(PGs) and epoxyeicosatrienoic acids (EETs). A similar result was
obtained in cultured bovine coronary endothelial cells. Inhibition of
the FAAH with diazomethylarachidonyl ketone blocked both the metabolism
of [3H]AEA and the
relaxations to AEA. Whole vessel and cultured endothelial cells
prelabeled with
[3H]arachidonic acid
synthesized [3H]PGs
and [3H]EETs, but not
[3H]AEA, in response
to A-23187. Furthermore, SR-141716A attenuated A-23187-stimulated
release of
[3H]arachidonic acid,
suggesting that it may have actions other than inhibition of CB1
receptor. These experiments suggest that AEA produces
endothelium-dependent vasorelaxation as a result of its catabolism to
arachidonic acid followed by conversion to vasodilatory eicosanoids
such as prostacyclin or the EETs.
coronary circulation; eicosanoids; endothelial cells; epoxyeicosatrienoic acids; prostaglandins; fatty acid amide hydrolase; endothelium-derived hyperpolarizing factor; N-acylethanolamines
This article has been cited by other articles:
![]() |
Y.-Y. Yang, H.-C. Lin, Y.-T. Huang, T.-Y. Lee, M.-C. Hou, Y.-W. Wang, F.-Y. Lee, and S.-D. Lee Roles of anandamide in the hepatic microcirculation in cirrhotic rats Am J Physiol Gastrointest Liver Physiol, February 1, 2006; 290(2): G328 - G334. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. J. Rademacher, S. Patel, W.-S. V. Ho, A. M. Savoie, N. J. Rusch, K. M. Gauthier, and C. J. Hillard U-46619 but not serotonin increases endocannabinoid content in middle cerebral artery: evidence for functional relevance Am J Physiol Heart Circ Physiol, June 1, 2005; 288(6): H2694 - H2701. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. M. Gauthier, D. V. Baewer, S. Hittner, C. J. Hillard, K. Nithipatikom, D. S. Reddy, J. R. Falck, and W. B. Campbell Endothelium-derived 2-arachidonylglycerol: an intermediate in vasodilatory eicosanoid release in bovine coronary arteries Am J Physiol Heart Circ Physiol, March 1, 2005; 288(3): H1344 - H1351. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Mukhopadhyay, B. M. Chapnick, and A. C. Howlett Anandamide-induced vasorelaxation in rabbit aortic rings has two components: G protein dependent and independent Am J Physiol Heart Circ Physiol, June 1, 2002; 282(6): H2046 - H2054. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Vanheel and J. Van de Voorde Regional Differences in Anandamide- and Methanandamide-Induced Membrane Potential Changes in Rat Mesenteric Arteries J. Pharmacol. Exp. Ther., April 13, 2001; 296(2): 322 - 328. [Abstract] [Full Text] |
||||
![]() |
C. J. Hillard Endocannabinoids and Vascular Function J. Pharmacol. Exp. Ther., July 1, 2000; 294(1): 27 - 32. [Abstract] [Full Text] |
||||
![]() |
D. Gebremedhin, A. R. Lange, W. B. Campbell, C. J. Hillard, and D. R. Harder Cannabinoid CB1 receptor of cat cerebral arterial muscle functions to inhibit L-type Ca2+ channel current Am J Physiol Heart Circ Physiol, June 1, 1999; 276(6): H2085 - H2093. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Fulton and J. Quilley Evidence against Anandamide as the Hyperpolarizing Factor Mediating the Nitric Oxide-Independent Coronary Vasodilator Effect of Bradykinin in the Rat J. Pharmacol. Exp. Ther., September 1, 1998; 286(3): 1146 - 1151. [Abstract] [Full Text] |
||||
![]() |
K. Varga, J. A. Wagner, D. T. Bridgen, and G. Kunos Platelet- and macrophage-derived endogenous cannabinoids are involved in endotoxin-induced hypotension FASEB J, August 1, 1998; 12(11): 1035 - 1044. [Abstract] [Full Text] |
||||
![]() |
S. Mukhopadhyay, B. M. Chapnick, and A. C. Howlett Anandamide-induced vasorelaxation in rabbit aortic rings has two components: G protein dependent and independent Am J Physiol Heart Circ Physiol, June 1, 2002; 282(6): H2046 - H2054. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |