251
|
Hanus L, Avraham Y, Ben-Shushan D, Zolotarev O, Berry EM, Mechoulam R. Short-term fasting and prolonged semistarvation have opposite effects on 2-AG levels in mouse brain. Brain Res 2003; 983:144-51. [PMID: 12914975 DOI: 10.1016/s0006-8993(03)03046-4] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
2-Arachidonoyl glycerol (2-AG) levels in whole mouse brain and two of its regions-hippocampus and hypothalamus-were determined after diet restriction (between 60 and 40%) lasting 12 days. The diet restriction lowered the level of 2-AG, which in the hypothalamus depended on the severity of the diet restriction, while the level in the hippocampus was not dependent on the diet regimen. As these observations differ from previously published data showing elevation of 2-AG levels in rat brain after 24 h of severe food restriction, we measured 2-AG levels in whole mouse brain after a comparable period of full starvation (fasting). We confirmed the elevation of 2-AG levels. It seems possible that these time-dependent variations of 2-AG levels may be of importance as a general coping strategy by animals during periods of starvation.
Collapse
Affiliation(s)
- Lumír Hanus
- Department of Medicinal Chemistry and Natural Products, Medical Faculty, Hebrew University, Ein Kerem Campus, Jerusalem 91120, Israel.
| | | | | | | | | | | |
Collapse
|
252
|
Kaplan BLF, Rockwell CE, Kaminski NE. Evidence for cannabinoid receptor-dependent and -independent mechanisms of action in leukocytes. J Pharmacol Exp Ther 2003; 306:1077-85. [PMID: 12805480 DOI: 10.1124/jpet.103.051961] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cannabinoids exhibit immunosuppressive actions that include inhibition of interleukin-2 production in response to a variety of T cell activation stimuli. Traditionally, the effects of these compounds have been attributed to cannabinoid receptors CB1 and CB2, both of which are expressed in mouse splenocytes. Therefore, N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorphenyl)-4-methyl-H-pyrazole-3 carboxyamidehydrochloride (SR141716A), a CB1 antagonist, and N-[(1S)-endo-1,3,3,-trimethyl-bicyclo[2,2,1]heptan-2-yl]-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide (SR144528), a CB2 antagonist, were used to investigate the role of cannabinoid receptors in the cannabinoid-induced inhibition of phorbol ester plus calcium ionophore (PMA/Io)-stimulated interleukin-2 production by mouse splenocytes. PMA/Io-stimulated interleukin-2 production was inhibited by cannabinol, cannabidiol, and both WIN 55212-2 stereoisomers with a rank order potency of R-(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-napthanlenyl) methanone mesylate (WIN 55212-2) approximately cannabidiol > S-(-)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-napthanlenyl) methanone mesylate (WIN 55212-3) approximately cannabinol. Cannabinoid-induced inhibition of PMA/Io-stimulated interleukin-2 was not attenuated by the presence of both SR144528 and SR141716A. Using pertussis toxin to address the role of G protein-coupled receptors in this response, it was determined that pertussis toxin treatment did not attenuate cannabinol-induced inhibition of PMA/Io-stimulated interleukin-2. With the demonstration that cannabinoid-induced inhibition of PMA/Io-stimulated interleukin-2 was not mediated via CB1 or CB2, alternative targets of cannabinoids in T cells were examined. Specifically, it was demonstrated that cannabinoids elevated intracellular calcium concentration in resting splenocytes and that the cannabinol-induced elevation in intracellular calcium concentration was attenuated by treatment with both SR144528 and SR141716A. Interestingly, pretreatment of splenocytes with agents that elevate intracellular calcium concentration inhibited PMA/Io-stimulated interleukin-2 production, suggesting that an elevation in intracellular calcium concentration might be involved in the mechanism of interleukin-2 inhibition. These studies suggest that immune modulation produced by cannabinoids involves multiple mechanisms, which might be both cannabinoid receptor-dependent and -independent.
Collapse
Affiliation(s)
- Barbara L Faubert Kaplan
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | | | | |
Collapse
|
253
|
Kishimoto S, Gokoh M, Oka S, Muramatsu M, Kajiwara T, Waku K, Sugiura T. 2-arachidonoylglycerol induces the migration of HL-60 cells differentiated into macrophage-like cells and human peripheral blood monocytes through the cannabinoid CB2 receptor-dependent mechanism. J Biol Chem 2003; 278:24469-75. [PMID: 12711605 DOI: 10.1074/jbc.m301359200] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
2-Arachidonoylglycerol is an endogenous ligand for the cannabinoid receptors (CB1 and CB2) and has been shown to exhibit a variety of cannabimimetic activities in vitro and in vivo. Recently, we proposed that 2-arachidonoylglycerol is the true endogenous ligand for the cannabinoid receptors, and both receptors (CB1 and CB2) are primarily 2-arachidonoylglycerol receptors. The CB1 receptor is assumed to be involved in the attenuation of neurotransmission. On the other hand, the physiological roles of the CB2 receptor, which is abundantly expressed in several types of leukocytes such as macrophages, still remain unknown. In this study, we examined the effects of 2-arachidonoylglycerol on the motility of HL-60 cells differentiated into macrophage-like cells. We found that 2-arachidonoylglycerol induces the migration of differentiated HL-60 cells. The migration induced by 2-arachidonoylglycerol was blocked by treatment of the cells with either SR144528, a CB2 receptor antagonist, or pertussis toxin, suggesting that the CB2 receptor and Gi/Go are involved in the 2-arachidonoylglycerol-induced migration. Several intracellular signaling molecules such as Rho kinase and mitogen-activated protein kinases were also suggested to be involved. In contrast to 2-arachidonoylglycerol, anandamide, another endogenous cannabinoid receptor ligand, failed to induce the migration. The 2-arachidonoylglycerol-induced migration was also observed for two other types of macrophage-like cells, the U937 cells and THP-1 cells, as well as human peripheral blood monocytes. These results strongly suggest that 2-arachidonoylglycerol induces the migration of several types of leukocytes such as macrophages/monocytes through a CB2 receptor-dependent mechanism thereby stimulating inflammatory reactions and immune responses.
Collapse
Affiliation(s)
- Seishi Kishimoto
- Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa 199-0195, Japan
| | | | | | | | | | | | | |
Collapse
|
254
|
Watanabe S, Doshi M, Hamazaki T. n-3 Polyunsaturated fatty acid (PUFA) deficiency elevates and n-3 PUFA enrichment reduces brain 2-arachidonoylglycerol level in mice. Prostaglandins Leukot Essent Fatty Acids 2003; 69:51-9. [PMID: 12878451 DOI: 10.1016/s0952-3278(03)00056-5] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
2-arachidonoylglycerol (2-AG) is a putative endogenous ligand for cannabinoid receptors and was suggested to play an important role in both physiological and pathological events in the central nervous system (CNS) as well as in peripheral organs. The sequential hydrolysis of arachidonic acid (20:4n-6, AA)-containing phospholipids has been proposed as a major biosynthetic route of 2-AG. On the other hand, the manipulation of the dietary n-3 polyunsaturated fatty acid (PUFA) status changes the AA level in tissue phospholipids. We, therefore, conducted two separate experiments to confirm whether the dietary n-3 PUFA status influences the 2-AG level in the mouse brain. In the first experiment, we fed mice with n-3 PUFA-deficient diet, which resulted in a marked decrease in the docosahexaenoic acid (22:6n-3, DHA) levels without a change in the AA level in brain phospholipids as compared with the mice fed with an n-3 PUFA-sufficient diet. The brain 2-AG level in the n-3 PUFA-deficient group was significantly higher than in the n-3 PUFA sufficient group. In the second experiment, we found that short-term supplementation of DHA-rich fish oil reduced brain 2-AG level as compared with the supplementation with low n-3 PUFA. The decrease in the AA level and the increase in the DHA level in the major phospholipids occurred in the brains of the mice fed the fish oil diet compared with those fed the low n-3 PUFA diet. Our results indicate that the n-3 PUFA deficiency elevates and n-3 PUFA enrichment reduces the brain 2-AG level in mice, suggesting that physiological and pathological events mediated by 2-AG through cannabinoid receptor in the CNS could be modified by the manipulation of the dietary n-3 PUFA status.
Collapse
Affiliation(s)
- S Watanabe
- Department of Clinical Application, Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, Japan.
| | | | | |
Collapse
|
255
|
Oka S, Tsuchie A, Tokumura A, Muramatsu M, Suhara Y, Takayama H, Waku K, Sugiura T. Ether-linked analogue of 2-arachidonoylglycerol (noladin ether) was not detected in the brains of various mammalian species. J Neurochem 2003; 85:1374-81. [PMID: 12787057 DOI: 10.1046/j.1471-4159.2003.01804.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
2-Eicosa-5',8',11',14'-tetraenylglycerol (2-AG ether, HU310, noladin ether) is a metabolically stable ether-linked analogue of 2-arachidonoylglycerol (2-AG), an endogenous cannabinoid receptor ligand. 2-AG ether has been used as a valuable experimental tool by a number of investigators. Recently, several groups reported that 2-AG ether is present in mammalian brains. We examined in detail whether 2-AG ether actually exists in the brains of various mammalian species. We found that 2-AG ether is not present, at least in an appreciable amount, in the rat brain by gas chromatography-mass spectrometry analysis and fluorometric high performance liquid chromatography analysis. The level of 2-AG ether in the rat brain was below 0.2 pmol/g brain, if at all present. Similar results were obtained for the mouse brain, hamster brain, guinea-pig brain and pig brain. The fact that 2-AG ether was not detected in the brains of various mammalian species is consistent with the fact that an ether bond is formed through enzymatic replacement of the fatty acyl moiety of 1-acyl dihydroxyacetone phosphate by a fatty alcohol, the resultant 1-O-alkyl dihydroxyacetone phosphate being a common intermediate of the biosynthesis of ether-linked lipids in mammalian tissues. It is rather questionable whether 2-AG ether is present in appreciable amounts in the brain and acts as an 'endogenous' cannabinoid receptor ligand.
Collapse
Affiliation(s)
- Saori Oka
- Department of Hygienic Chemistry and Nutrition, Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan
| | | | | | | | | | | | | | | |
Collapse
|
256
|
Woodward DF, Krauss AHP, Chen J, Liang Y, Li C, Protzman CE, Bogardus A, Chen R, Kedzie KM, Krauss HA, Gil DW, Kharlamb A, Wheeler LA, Babusis D, Welty D, Tang-Liu DDS, Cherukury M, Andrews SW, Burk RM, Garst ME. Pharmacological characterization of a novel antiglaucoma agent, Bimatoprost (AGN 192024). J Pharmacol Exp Ther 2003; 305:772-85. [PMID: 12606640 DOI: 10.1124/jpet.102.047837] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Replacement of the carboxylic acid group of prostaglandin (PG) F(2alpha) with a nonacidic moiety, such as hydroxyl, methoxy, or amido, results in compounds with unique pharmacology. Bimatoprost (AGN 192024) is also a pharmacologically novel PGF(2alpha) analog, where the carboxylic acid is replaced by a neutral ethylamide substituent. Bimatoprost potently contracted the feline lung parenchymal preparation (EC(50) value of 35-55 nM) but exhibited no meaningful activity in a variety of PG-sensitive tissue and cell preparations. Its activity seemed unrelated to FP receptor stimulation according to the following evidence. 1) Bimatoprost exhibited no meaningful activity in tissues and cells containing functional FP receptors. 2) Bimatoprost activity in the cat lung parenchyma is not species-specific because its potent activity in this preparation could not be reproduced in cells stably expressing the feline FP receptor. 3) Radioligand binding studies using feline and human recombinant FP receptors exhibited minimal competition versus [(3)H]17-phenyl PGF(2a) for Bimatoprost. 4) Bimatoprost pretreatment did not attenuate PGF(2alpha)-induced Ca(2+) signals in Swiss 3T3 cells. 5) Regional differences were apparent for Bimatoprost but not FP agonist effects in the cat lung. Bimatoprost reduced intraocular pressure in ocular normotensive and hypertensive monkeys over a 0.001 to 0.1% dose range. A single-dose and multiple-dose ocular distribution/metabolism studies using [(3)H]Bimatoprost (0.1%) were performed. Within the globe, bimatoprost concentrations were 10- to 100-fold higher in anterior segment tissues compared with the aqueous humor. Bimatoprost was overwhelmingly the predominant molecular species identified at all time points in ocular tissues, indicating that the intact molecule reduces intraocular pressure.
Collapse
Affiliation(s)
- D F Woodward
- Department of Biological Sciences, Allergan, Inc., 2525 Dupont Dr., Irvine, CA 92612, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
257
|
Rukwied R, Watkinson A, McGlone F, Dvorak M. Cannabinoid agonists attenuate capsaicin-induced responses in human skin. Pain 2003; 102:283-288. [PMID: 12670670 DOI: 10.1016/s0304-3959(02)00401-3] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The induction of hyperalgesia upon capsaicin administration requires activation of specific sub-classes of nociceptive afferent C-fibres providing nociceptive input to the central nervous system. It has been demonstrated in animal models that the endocannabinoid anandamide has anti-hyperalgesic properties upon capsaicin stimulation, albeit it also binds to vanilloid receptors. In the present study we topically administered the cannabinoid receptor ligand HU210 to human skin and investigated its effects on capsaicin-induced pain and hyperalgesia.We demonstrated that pre-treatment with HU210 significantly reduced the perception of pain following the administration of capsaicin. Heat pain thresholds were significantly reduced by capsaicin application measured 5 and 30min after administration. In contrast, at the HU210 pre-treated skin sites capsaicin failed to induce heat hyperalgesia during the fifth minute of administration. Secondary mechanical hyperalgesia to touch (allodynia) was measured during the fifth, 15th and 30th minute after capsaicin administration. In comparison to the ethanol control site, the area of touch-evoked allodynia was significantly reduced at the HU210 skin site during the first two measures. However, 30min after the administration of capsaicin no significant differences of allodynia were observed between the HU210 and ethanol pre-treated skin. The present study provided evidence for analgesic and anti-hyperalgesic properties of a topically applied cannabinoid receptor ligand, which might have important therapeutic implications in humans.
Collapse
Affiliation(s)
- Roman Rukwied
- Unilever Research & Development Port Sunlight, DPC 3-1, Wirral CH63 3JW, UK Unilever Research Colworth Laboratory, Colworth House, Sharnbrook MK44 1LQ, UK School of Biological Sciences, The University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK
| | | | | | | |
Collapse
|
258
|
Abstract
During neuroinflammation, activated microglial cells migrate toward dying neurons, where they exacerbate local cell damage. The signaling molecules that trigger microglial cell migration are poorly understood. In this paper, we show that pathological overstimulation of neurons by glutamate plus carbachol dramatically increases the production of the endocannabinoid 2-arachidonylglycerol (2-AG) but only slightly increases the production of anandamide and does not affect the production of two putative endocannabinoids, homo-gamma-linolenylethanolamide and docosatetraenylethanolamide. We further show that pathological stimulation of microglial cells with ATP also increases the production of 2-AG without affecting the amount of other endocannabinoids. Using a Boyden chamber assay, we provide evidence that 2-AG triggers microglial cell migration. This effect of 2-AG occurs through CB2 and abnormal-cannabidiol-sensitive receptors, with subsequent activation of the extracellular signal-regulated kinase 1/2 signal transduction pathway. It is important to note that cannabinol and cannabidiol, two nonpsychotropic ingredients present in the marijuana plant, prevent the 2-AG-induced cell migration by antagonizing the CB2 and abnormal-cannabidiol-sensitive receptors, respectively. Finally, we show that microglial cells express CB2 receptors at the leading edge of lamellipodia, which is consistent with the involvement of microglial cells in cell migration. Our study identifies a cannabinoid signaling system regulating microglial cell migration. Because this signaling system is likely to be involved in recruiting microglial cells toward dying neurons, we propose that cannabinol and cannabidiol are promising nonpsychotropic therapeutics to prevent the recruitment of these cells at neuroinflammatory lesion sites.
Collapse
|
259
|
Lau AHY, Chow SSM. Effects of cannabinoid receptor agonists on immunologically induced histamine release from rat peritoneal mast cells. Eur J Pharmacol 2003; 464:229-35. [PMID: 12620517 DOI: 10.1016/s0014-2999(03)01430-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Immunologic activation of mast cells through the cross-linking of high affinity IgE receptors results in the release of inflammatory mediators which are important in the pathogenesis of allergic reactions. Early studies investigating the effects of palmitoylethanolamide on animal models of inflammation and on rat mast cells led to the hypothesis that endogenous cannabinoids might act as local autacoids which suppressed inflammation by reducing the activation of mast cells. However, more recent studies produced contradicting results. In order to evaluate if cannabinoid receptors are present in mast cells, we studied the effects of endocannabinoids (anandamide and palmitoylethanolamide) and synthetic cannabimimetics (CP 55,940, WIN 55,212-2 and HU-210) on histamine release from rat peritoneal mast cells. When incubated with mast cells alone, only anandamide could induce significant level of histamine release at concentrations higher than 10(-6) M. When mast cells were activated with anti-IgE, the histamine release induced was not affected by anandamide, palmitoylethanolamide and CP 55,940. In contrast, both WIN 55,212-2 and HU-210 enhanced anti-IgE-induced histamine release at 10(-5) M and preincubation did not increase the potency. The histamine releasing action of anandamide and the enhancing effects of WIN 55,212-2 and HU-210 on anti-IgE-induced histamine release were not reduced by the cannabinoid receptor antagonists, AM 281 and AM 630. In conclusion, the present study does not support the hypothesis that cannabinoids suppress mast cell activation. Instead, some of the cannabinoid receptor-directed ligands tested enhanced mast cell activation. However, the high concentrations required and the failure of cannabinoid receptor antagonists to reverse such effects also question the existence of functional cannabinoid receptors in mast cells.
Collapse
Affiliation(s)
- Alaster H Y Lau
- Department of Pharmacology, Faculty of Medicine, Chinese University of Hong Kong, Basic Medical Sciences Building, Shatin, New Territories, China.
| | | |
Collapse
|
260
|
Bouchard JF, Lépicier P, Lamontagne D. Contribution of endocannabinoids in the endothelial protection afforded by ischemic preconditioning in the isolated rat heart. Life Sci 2003; 72:1859-70. [PMID: 12586223 DOI: 10.1016/s0024-3205(02)02474-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of the present study was to assess the contribution of endogenous cannabinoids in the protective effect of ischemic preconditioning on the endothelial function in coronary arteries of the rat. Isolated rat hearts were exposed to a 30-min low flow ischemia (1 ml/min) followed by 20-min reperfusion, after which the response to the endothelium-dependent vasodilator, serotonine (5-HT), was compared with that of the endothelium-independent vasodilator, sodium nitroprusside (SNP). In untreated hearts, ischemia-reperfusion diminished selectively 5-HT-induced vasodilatation, compared with time-matched sham hearts, the vasodilatation to SNP being unaffected. A 5-min zero-flow preconditioning ischemia in untreated hearts preserved the vasodilatation produced by 5-HT. Blockade of either CB(1)-receptors with SR141716A or CB(2)-receptors with SR144528 abolished the protective effect of preconditioning on the 5-HT vasodilatation. Perfusion with either palmitoylethanolamide or 2-arachidonoylglycerol 15 min before and throughout the ischemia mimicked preconditioning inasmuch as it protected the endothelium in a similar fashion. This protection was blocked by SR144528 in both cases, whereas SR141716A only blocked the effect of PEA. The presence of CB(1) and CB(2)-receptors in isolated rat hearts was confirmed by Western blots. In conclusion, the data suggest that endogenous cannabinoids contribute to the endothelial protective effect of ischemic preconditioning in rat coronary arteries.
Collapse
MESH Headings
- Amides
- Animals
- Arachidonic Acids
- Blotting, Western
- Camphanes/pharmacology
- Cannabinoid Receptor Modulators
- Cannabinoids/antagonists & inhibitors
- Coronary Vessels/drug effects
- Coronary Vessels/metabolism
- Endocannabinoids
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Ethanolamines
- Fatty Acids, Unsaturated/pharmacology
- Fatty Acids, Unsaturated/physiology
- Glycerides/pharmacology
- Heart/drug effects
- Heart/physiopathology
- Ischemic Preconditioning, Myocardial
- Male
- Myocardium/metabolism
- Nitroprusside/pharmacology
- Palmitic Acids/pharmacology
- Piperidines/pharmacology
- Pyrazoles/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptor, Cannabinoid, CB2
- Receptors, Cannabinoid
- Receptors, Drug/metabolism
- Rimonabant
- Serotonin/pharmacology
- Vasodilation/drug effects
Collapse
Affiliation(s)
- Jean-François Bouchard
- Faculté de pharmacie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, QC, Canada H3C 3J7
| | | | | |
Collapse
|
261
|
Jordà MA, Lowenberg B, Delwel R. The peripheral cannabinoid receptor Cb2, a novel oncoprotein, induces a reversible block in neutrophilic differentiation. Blood 2003; 101:1336-43. [PMID: 12406867 DOI: 10.1182/blood-2002-07-2034] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously identified a novel common virus integration site, Evi11, by means of retroviral insertional mutagenesis. We demonstrated that the gene encoding the peripheral cannabinoid receptor (Cb2) is the potential target, suggesting that Cb2 is a proto-oncogene. To elucidate a role for this G protein-coupled receptor (GPCR) in leukemic transformation we generated a Cb2-EGFP cDNA construct that was introduced into 32D/G-CSF-R cells. These cells require interleukin 3 (IL-3) to proliferate in vitro, whereas in the presence of granulocyte-colony-stimulating factor (G-CSF) they differentiate toward mature neutrophils. We demonstrate that 32D/G-CSF-R/Cb2-EGFP cells migrate in a transwell assay in reponse to the Cb2 ligand 2-arachidonoylglycerol (2-AG), indicating that the fusion protein was functional. When cultured in the presence of G-CSF neutrophilic differentiation of Cb2-EGFP-expressing 32D/G-CSF-R cells was completely blocked. Moreover, a Cb2-specific antagonist fully recovered the G-CSF-induced neutrophilic differentiation of 32D/G-CSF-R/Cb2-EGFP cells. To investigate which signal transduction pathway(s) may be involved in the block of neutrophilic maturation, differentiation experiments were carried out using specific inhibitors of signaling routes. Interestingly, full rescue of G-CSF-induced neutrophilic differentiation was observed when cells were cultured with the mitogen-induced extracellular kinase (MEK) inhibitors, PD98059 or U0126, and partial recovery was detected with the phosphoinositide 3-kinase (PI3-K) inhibitor LY-294002. These studies demonstrate that the Cb2 receptor is an oncoprotein that blocks neutrophilic differentiation when overexpressed in myeloid precursor cells. Cb2 appears to mediate its activity through MEK/extracellular signal-related kinase (ERK) and PI3-K pathways.
Collapse
|
262
|
Schmid HHO, Schmid PC, Berdyshev EV. Cell signaling by endocannabinoids and their congeners: questions of selectivity and other challenges. Chem Phys Lipids 2002; 121:111-34. [PMID: 12505695 DOI: 10.1016/s0009-3084(02)00157-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The major endocannabinoids, anandamide (N-arachidonoylethanolamide, 20:4n-6 N-acylethanolamine) and 2-arachidonoylglycerol (2-AG) are structurally and functionally similar, but they are produced by different metabolic pathways and their levels must therefore be regulated by different mechanisms. Both endocannabinoids are accompanied by cannabinoid receptor-inactive, saturated and mono- or di-unsaturated congeners which can influence their metabolism and function. Here we review published data on the presence and production of anandamide and 2-AG and their congeners in mammalian cells and discuss this information in terms of their proposed signaling functions.
Collapse
Affiliation(s)
- Harald H O Schmid
- The Hormel Institute, University of Minnesota, 801-16th Avenue N E, Austin, MN 55912, USA.
| | | | | |
Collapse
|
263
|
Rouzer CA, Ghebreselasie K, Marnett LJ. Chemical stability of 2-arachidonylglycerol under biological conditions. Chem Phys Lipids 2002; 119:69-82. [PMID: 12270674 DOI: 10.1016/s0009-3084(02)00068-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recent evidence indicates that 2-arachidonylglycerol (2-AG) is a potent and specific ligand for the central and peripheral cannabinoid receptors. Therefore, the chemical stability of this molecule under biological conditions is of interest. A method for the isolation and detection of 2-AG using HPLC with evaporative light scattering detection is described. The method provides an extraction recovery from aqueous media of 78%, and a limit of detection of 60 ng on column. Incubation of 2-AG in culture medium or biological buffers indicated that it is stable to oxidation and ester hydrolysis for up to 6 h at 37 degrees C. However, gradual disappearance of the compound was noted due to adherence to glass and plastic surfaces. During incubation in RPMI culture medium, 2-AG rearranged to 1(3)-arachidonylglycerol (1(3)-AG) in a first order process with a half-life of 10 min in the absence of serum and 2.3 min in the presence of 10% fetal calf serum. Further studies indicated that the acyl migration reaction is base catalyzed (k(cat)=78,000/min M), and that the reaction is affected slightly by changes in buffer (Tris) concentration and not at all by changes in ionic strength. The results indicate that 2-AG is readily converted to 1(3)-AG under conditions commonly used to study receptor-ligand interactions, findings that have significant implications for the interpretation of relative ligand potency between the two isomers.
Collapse
Affiliation(s)
- Carol A Rouzer
- Department of Biochemistry, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA.
| | | | | |
Collapse
|
264
|
van der Stelt M, Veldhuis WB, Maccarrone M, Bär PR, Nicolay K, Veldink GA, Di Marzo V, Vliegenthart JFG. Acute neuronal injury, excitotoxicity, and the endocannabinoid system. Mol Neurobiol 2002; 26:317-46. [PMID: 12428763 DOI: 10.1385/mn:26:2-3:317] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The endocannabinoid system is a valuable target for drug discovery, because it is involved in the regulation of many cellular and physiological functions. The endocannabinoid system constitutes the endogenous lipids anandamide, 2-arachidonoylglycerol and noladin ether, and the cannabinoid CB1 and CB2 receptors as well as the proteins for their inactivation. It is thought that (endo)cannabinoid-based drugs may potentially be useful to reduce the effects of neurodegeneration. This paper reviews recent developments in the endocannabinoid system and its involvement in neuroprotection. Exogenous (endo)cannabinoids have been shown to exert neuroprotection in a variety of in vitro and in vivo models of neuronal injury via different mechanisms, such as prevention of excitotoxicity by CB1-mediated inhibition of glutamatergic transmission, reduction of calcium influx, and subsequent inhibition of deleterious cascades, TNF-alpha formation, and anti-oxidant activity. It has been suggested that the release of endogenous endocannabinoids during neuronal injury might be a protective response. However, several observations indicate that the role of the endocannabinoid system as a general endogenous protection system is questionable. The data are critically reviewed and possible explanations are given.
Collapse
Affiliation(s)
- Mario van der Stelt
- Department of Bio-Organic Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
265
|
Abstract
Cannabinoid receptors were named because they have affinity for the agonist delta9-tetrahydrocannabinol (delta9-THC), a ligand found in organic extracts from Cannabis sativa. The two types of cannabinoid receptors, CB1 and CB2. are G protein coupled receptors that are coupled through the Gi/o family of proteins to signal transduction mechanisms that include inhibition of adenylyl cyclase, activation of mitogen-activated protein kinase, regulation of calcium and potassium channels (CB1 only), and other signal transduction pathways. A class of the eicosanoid ligands are relevant to lipid-mediated cellular signaling because they serve as endogenous agonists for cannabinoid receptors, and are thus referred to as endocannabinoids. Those compounds identified to date include the eicosanoids arachidonoylethanolamide (anandamide), 2-arachidonoylglycerol and 2-arachidonylglyceryl ether (noladin ether). Several excellent reviews on endocannabinoids and their synthesis, metabolism and function have appeared in recent years. This paper will describe the biological activities, pharmacology, and signal transduction mechanisms for the cannabinoid receptors, with particular emphasis on the responses to the eicosanoid ligands.
Collapse
Affiliation(s)
- Allyn C Howlett
- Julius L Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham 27707, USA.
| |
Collapse
|
266
|
Romero J, Lastres-Becker I, de Miguel R, Berrendero F, Ramos JA, Fernández-Ruiz J. The endogenous cannabinoid system and the basal ganglia. biochemical, pharmacological, and therapeutic aspects. Pharmacol Ther 2002; 95:137-52. [PMID: 12182961 DOI: 10.1016/s0163-7258(02)00253-x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
New data strengthen the idea of a prominent role for endocannabinoids in the modulation of a wide variety of neurobiological functions. Among these, one of the most important is the control of movement. This finding is supported by 3 lines of evidence: (1) the demonstration of a powerful action, mostly inhibitory in nature, of synthetic and plant-derived cannabinoids and, more recently, of endocannabinoids on motor activity; (2) the presence of the cannabinoid CB(1) receptor subtype and the recent description of endocannabinoids in the basal ganglia and the cerebellum, the areas that control movement; and (3) the fact that CB(1) receptor binding was altered in the basal ganglia of humans affected by several neurological diseases and also of rodents with experimentally induced motor disorders. Based on this evidence, it has been suggested that new synthetic compounds that act at key steps of endocannabinoid activity (i.e., more-stable analogs of endocannabinoids, inhibitors of endocannabinoid reuptake or metabolism, antagonists of CB(1) receptors) might be of interest for their potential use as therapeutic agents in a variety of pathologies affecting extrapyramidal structures, such as Parkinson's and Huntington's diseases. Currently, only a few data exist in the literature studying such relationships in humans, but an increasing number of journal articles are revealing the importance of this new neuromodulatory system and arguing in favour of the funding of more extensive research in this field. The present article will review the current knowledge of this neuromodulatory system, trying to establish the future lines for research on the therapeutic potential of the endocannabinoid system in motor disorders.
Collapse
Affiliation(s)
- Julián Romero
- Laboratorio de Apoyo a la Investigación, Fundación Hospital Alcorcón, Madrid, Spain
| | | | | | | | | | | |
Collapse
|
267
|
Hansen HS, Moesgaard B, Petersen G, Hansen HH. Putative neuroprotective actions of N-acyl-ethanolamines. Pharmacol Ther 2002; 95:119-26. [PMID: 12182959 DOI: 10.1016/s0163-7258(02)00251-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
N-Acyl-ethanolamines (NAEs) and their precursors, N-acyl-ethanolamine phospholipids (NAPEs), are present in the mammalian brain at levels of a few hundred picomoles/gram tissue and a few nanomoles/gram tissue, respectively. NAE-containing arachidonic acid is called anandamide, and it has attracted particular attention since it is a partial agonist for the cannabinoid receptors, for which 2-arachidonoylglycerol is the full agonist. In addition, anandamide may also activate the vanilloid receptor. Anandamide usually amounts to 1-10% of NAEs, as the vast majority of N-acyl groups are saturated and monounsaturated fatty acids. Formation of NAPE and NAE is catalyzed by an N-acyltransferase and an NAPE-hydrolyzing phospholipase D, respectively, two enzymes that have been characterized only preliminary. Interestingly, NAPEs and NAEs accumulate in the brain in response to neurodegenerative insults at a time when other phospholipids are subjected to rapid degradation. This is an important biosynthetic aspect of NAPE and NAE, as NAEs may be neuroprotective by a number of different mechanisms involving both receptor activation and non-receptor-mediated effects, e.g. by binding to cannabinoid receptors and interfering with ceramide turnover, respectively.
Collapse
Affiliation(s)
- Harald S Hansen
- Department of Pharmacology, The Royal Danish School of Pharmacy, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
| | | | | | | |
Collapse
|
268
|
Kozak KR, Gupta RA, Moody JS, Ji C, Boeglin WE, DuBois RN, Brash AR, Marnett LJ. 15-Lipoxygenase metabolism of 2-arachidonylglycerol. Generation of a peroxisome proliferator-activated receptor alpha agonist. J Biol Chem 2002; 277:23278-86. [PMID: 11956198 DOI: 10.1074/jbc.m201084200] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The recent demonstrations that cyclooxygenase-2 and leukocyte-type 12-lipoxygenase (LOX) efficiently oxygenate 2-arachidonylglycerol (2-AG) prompted an investigation into related oxygenases capable of metabolizing this endogenous cannabinoid receptor ligand. We evaluated the ability of six LOXs to catalyze the hydroperoxidation of 2-AG. Soybean 15-LOX, rabbit reticulocyte 15-LOX, human 15-LOX-1, and human 15-LOX-2 oxygenate 2-AG, providing 15(S)-hydroperoxyeicosatetraenoic acid glyceryl ester. In contrast, potato and human 5-LOXs do not efficiently metabolize this endocannabinoid. Among a series of structurally related arachidonyl esters, arachidonylglycerols serve as the preferred substrates for 15-LOXs. Steady-state kinetic analysis demonstrates that both 15-LOX-1 and 15-LOX-2 oxygenate 2-AG comparably or preferably to arachidonic acid. Furthermore, 2-AG treatment of COS-7 cells transiently transfected with human 15-LOX expression vectors or normal human epidermal keratinocytes results in the production and extracellular release of 15-hydroxyeicosatetraenoic acid glyceryl ester (15-HETE-G), establishing that lipoxygenase metabolism of 2-AG occurs in an eukaryotic cellular environment. Investigations into the potential biological actions of 15-HETE-G indicate that this lipid, in contrast to its free-acid counterpart, acts as a peroxisome proliferator-activated receptor alpha agonist. The results demonstrate that 15-LOXs are capable of acting on 2-AG to provide 15-HETE-G and elucidate a potential role for endocannabinoid oxygenation in the generation of peroxisome proliferator-activated receptor alpha agonists.
Collapse
Affiliation(s)
- Kevin R Kozak
- Department of Biochemistry, Vanderbilt-Ingram Cancer Center and Center in Molecular Toxicology, Nashville, Tennessee, USA
| | | | | | | | | | | | | | | |
Collapse
|
269
|
Jordà MA, Verbakel SE, Valk PJM, Vankan-Berkhoudt YV, Maccarrone M, Finazzi-Agrò A, Löwenberg B, Delwel R. Hematopoietic cells expressing the peripheral cannabinoid receptor migrate in response to the endocannabinoid 2-arachidonoylglycerol. Blood 2002; 99:2786-93. [PMID: 11929767 DOI: 10.1182/blood.v99.8.2786] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cb2 is a novel protooncogene encoding the peripheral cannabinoid receptor. Previous studies demonstrated that 2 distinct noncoding first exons exist: exon-1A and exon-1B, which both splice to protein-coding exon-2. We demonstrate that in retrovirally induced murine myeloid leukemia cells with proviral insertion in Cb2, exon-1B/exon-2 Cb2 messenger RNA levels have been increased, resulting in high receptor numbers. In myeloid leukemia cells without virus insertion in this locus, low levels of only exon-1A/exon-2 Cb2 transcripts were present and receptors could not be detected. To elucidate the function of Cb2 in myeloid leukemia cells, a set of in vitro experiments was carried out using 32D/G-CSF-R (granulocyte colony-stimulating factor receptor) cells transfected with exon-1B/exon-2 Cb2 complementary DNA and a myeloid cell line carrying a virus insertion in Cb2 (ie, NFS 78). We demonstrate that a major function of the Cb2 receptor is stimulation of migration as determined in a transwell assay. Exposure of Cb2-expressing cells to different cannabinoids showed that the true ligand for Cb2 is 2-arachidonoylglycerol (2-AG), which may act as chemoattractant and as a chemokinetic agent. Furthermore, we observed a significant synergistic activity between 2-AG and interleukin-3 or G-CSF, suggesting cross-talk between the different receptor systems. Radioactive-ligand binding studies revealed significant numbers of Cb2 receptors in normal spleen. Transwell experiments carried out with normal mouse spleen cells showed 2-AG-induced migration of B220-, CD19-, immunoglobulin M-, and immunoglobulin D-expressing B lymphocytes. Our study demonstrates that a major function of Cb2 receptor expressed on myeloid leukemia cells or normal splenocytes is stimulation of migration.
Collapse
|
270
|
Schmid HHO, Berdyshev EV. Cannabinoid receptor-inactive N-acylethanolamines and other fatty acid amides: metabolism and function. Prostaglandins Leukot Essent Fatty Acids 2002; 66:363-76. [PMID: 12052050 DOI: 10.1054/plef.2001.0348] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although it is now generally accepted that long-chain N-acylethanolamines and their precursors, N-acylethanolamine phospholipids, exist as trace constituents in virtually all vertebrate cells and tissues, their possible biological functions are just emerging. While anandamide (N-arachidonoylethanolamine) has received much attention due to its ability to bind to and activate cannabinoid receptors, the saturated and monounsaturated N-acylethanolamines, which usually represent the vast majority, are cannabinoid receptor-inactive but appear to interact with endocannabinoids and to have other signaling functions as well. Also, primary fatty acid amides, including the amide of oleic acid, which acts as a sleep-inducing agent, do not interact with cannabinoid receptors but are catabolically related to endocannabinoids. Here we review published information on the occurrence, metabolism, and possible signaling functions of the cannabinoid receptor-inactive N-acylethanolamines and primary fatty acid amides.
Collapse
Affiliation(s)
- H H O Schmid
- The Hormel Institute, University of Minnesota, 801-16th Avenue NE, Austin, MN 55912, USA.
| | | |
Collapse
|
271
|
Reggio PH. Endocannabinoid structure-activity relationships for interaction at the cannabinoid receptors. Prostaglandins Leukot Essent Fatty Acids 2002; 66:143-60. [PMID: 12052032 DOI: 10.1054/plef.2001.0343] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Anandamide (N -arachidonoylethanolamine) was the first ligand to be identified as an endogenous ligand of the G-protein coupled cannabinoid CB1 receptor. Subsequently, two other fatty acid ethanolamides, N -homo- gamma -linolenylethanolamine and N -7,10,13,16-docosatetraenylethanolamine were identified as endogenous cannabinoid ligands. A fatty acid ester, 2-arachidonoylglycerol (2-AG), and a fatty acid ether, 2-arachidonyl glyceryl ether also have been isolated and shown to be endogenous cannabinoid ligands. Recent studies have postulated the existence of carrier-mediated anandamide transport that is essential for termination of the biological effects of anandamide. A membrane bound amidohydrolase (fatty acid amide hydrolase, FAAH), located intracellularly, hydrolyzes and inactivates anandamide and other endogenous cannabinoids such as 2-AG. 2-AG has also been proposed to be an endogenous CB2 ligand. Structure-activity relationships (SARs) for endocannabinoid interaction with the CB receptors are currently emerging in the literature. This review considers cannabinoid receptor SAR developed to date for the endocannabinoids with emphasis upon the conformational implications for endocannabinoid recognition at the cannabinoid receptors.
Collapse
Affiliation(s)
- Patricia H Reggio
- Department of Chemistry, Kennesaw State University, 1000 Chastain Road, Kennesaw, GA 30144, USA.
| |
Collapse
|
272
|
McAllister SD, Glass M. CB(1) and CB(2) receptor-mediated signalling: a focus on endocannabinoids. Prostaglandins Leukot Essent Fatty Acids 2002; 66:161-71. [PMID: 12052033 DOI: 10.1054/plef.2001.0344] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The discovery that the major psychoactive component of marijuana activated two G-protein coupled receptors prompted the search for the endogenous cannabinoid ligands now termed endocannabinoids. To date three putative ligands have been isolated, all consisting of arachidonic acid linked to a polar head group. Both synthetic and endogenous cannabinoids have been the focus of extensive study over the past few years. The signalling events produced by endocannabinoids as compared with Delta(9) -THC and synthetic cannabinoids contain many similarities. However, as research focuses more on endogenous ligands the divergence between these classes of compounds grows. This review focuses upon the developments in endocannabinoid signal transduction from receptor-mediated activation of common G-protein linked effector pathways through downstream regulation of gene transcription.
Collapse
Affiliation(s)
- Sean D McAllister
- Forbes Norris ALS Research Center, California Pacific Medical Centre, 2351 Clay Street, Suite 416, San Francisco, CA 94115, USA
| | | |
Collapse
|
273
|
Stamatov SD, Stawinski J. Novel, regioselective transformation of an oxirane system. An efficient approach to the synthesis of endocannabinoid 2-arachidonoylglycerol. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)00116-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
274
|
Rice ASC, Farquhar-Smith WP, Nagy I. Endocannabinoids and pain: spinal and peripheral analgesia in inflammation and neuropathy. Prostaglandins Leukot Essent Fatty Acids 2002; 66:243-56. [PMID: 12052040 DOI: 10.1054/plef.2001.0362] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Analgesia is an important physiological function of the endocannabinoid system and one of significant clinical relevance. This review discusses the analgesic effects of endocannabinoids at spinal and peripheral levels, firstly by describing the physiological framework for analgesia and secondly by reviewing the evidence for analgesic effects of endocannabinoids obtained using animal models of clinical pain conditions. In the spinal cord, CB(1) receptors have been demonstrated in laminae of the dorsal horn intimately concerned with the processing of nociceptive information and the modulation thereof. Similarly, CB(1) receptors have been demonstrated on the cell bodies of primary afferent neurones; however, the exact phenotype of cells which express this receptor requires further elucidation. Local administration, peptide release and electrophysiological studies support the concept of spinally mediated endocannabinoid-induced analgesia. Whilst a proportion of the peripheral analgesic effect of endocannabinoids can be attributed to a neuronal mechanism acting through CB(1) receptors expressed by primary afferent neurones, the antiinflammatory actions of endocannabinoids, mediated through CB(2) receptors, also appears to contribute to local analgesic effects. Possible mechanisms of this CB(2)-mediated effect include the attenuation of NGF-induced mast cell degranulation and of neutrophil accumulation, both of which are processes known to contribute to the generation of inflammatory hyperalgesia. The analgesic effects of cannabinoids have been demonstrated in models of somatic and visceral inflammatory pain and of neuropathic pain, the latter being an important area of therapeutic need. Analgesia is one of the principal therapeutic targets of cannabinoids. This review will discuss the analgesic effects of endocannabinoids in relation to two areas of therapeutic need, persistent inflammation and neuropathic pain. The more general aspects of the role of cannabinoids, endogenous and exogenous, in analgesia have been recently reviewed elsewhere (Rice, Curr Opi Invest Drugs 2001; 2: 399-414; Pertwee, Prog Neurobil 2001; 63: 569-611; Rice, Mackie, In: Evers A. S, ed. Anesthetic Pharmacology: Physiologic Principles and Clinical Practice. St. Louis: Harcourt Health Sciences, 2002). Since a major goal in the development of cannabinoid-based analgesics is to divorce the antinociceptive effects from the psychotrophic effects, the discussion will focus on the antinociceptive effects produced at the spinal cord and/or peripheral level as these areas are the most attractive targets in this regard. A mechanistic discussion of the "framework" for analgesia will be followed by a description of studies examining the role of endocannabinoids in relieving pain; since the elucidation of these effects was undertaken using synthetic cannabinoids, reference will also be made to such studies, in the context of endocannabinoids.
Collapse
Affiliation(s)
- A S C Rice
- Department of Anaesthetics, Pain Research Group, Inperial College of Science, Technology and Medicine, Chelsea and Westminster Hospital Campus, 369 Fulham Road, London SW10 9NH, UK.
| | | | | |
Collapse
|
275
|
Sugiura T, Kobayashi Y, Oka S, Waku K. Biosynthesis and degradation of anandamide and 2-arachidonoylglycerol and their possible physiological significance. Prostaglandins Leukot Essent Fatty Acids 2002; 66:173-92. [PMID: 12052034 DOI: 10.1054/plef.2001.0356] [Citation(s) in RCA: 243] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
N -arachidonoylethanolamine (anandamide) was the first endogenous cannabinoid receptor ligand to be discovered. Dual synthetic pathways for anandamide have been proposed. One is the formation from free arachidonic acid and ethanolamine, and the other is the formation from N -arachidonoyl phosphatidylethanolamine (PE) through the action of a phosphodiesterase. These pathways, however, do not appear to be able to generate a large amount of anandamide, at least under physiological conditions. The generation of anandamide from free arachidonic acid and ethanolamine is catalyzed by a degrading enzyme anandamide amidohydrolase/fatty acid amide hydrolase operating in reverse and requires large amounts of substrates. As for the second pathway, arachidonic acids esterified at the 1-position of glycerophospholipids, which are mostly esterified at the 2-position, are utilized for the formation of N -arachidonoyl PE, a stored precursor form of anandamide. In fact, the actual levels of anandamide in various tissues are generally low except in a few cases. 2-Arachidonoylglycerol (2-AG) was the second endogenous cannabinoid receptor ligand to be discovered. 2-AG is a degradation product of arachidonic acid-containing glycerophospholipids such as inositol phospholipids. Several investigators have demonstrated that 2-AG is produced in a variety of tissues and cells upon stimulation. 2-AG acts as a full agonist at the cannabinoid receptors (CB1 and CB2). Evidence is gradually accumulating and indicates that 2-AG is the most efficacious endogenous natural ligand for the cannabinoid receptors. In this review, we summarize the tissue levels, biosynthesis, degradation and possible physiological significance of two endogenous cannabimimetic molecules, anandamide and 2-AG.
Collapse
Affiliation(s)
- T Sugiura
- Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Tsukui-gun, Kanagawa 199-0195, Japan.
| | | | | | | |
Collapse
|
276
|
Parolaro D, Massi P, Rubino T, Monti E. Endocannabinoids in the immune system and cancer. Prostaglandins Leukot Essent Fatty Acids 2002; 66:319-32. [PMID: 12052046 DOI: 10.1054/plef.2001.0355] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The present review focuses on the role of the endogenous cannabinoid system in the modulation of immune response and control of cancer cell proliferation. The involvement of cannabinoid receptors, endogenous ligands and enzymes for their biosynthesis and degradation, as well as of cannabinoid receptor-independent events is discussed. The picture arising from the recent literature appears very complex, indicating that the effects elicited by the stimulation of the endocannabinoid system are strictly dependent on the specific compounds and cell types considered. Both the endocannabinoid anandamide and its congener palmitoylethanolamide, exert a negative action in the onset of a variety of parameters of the immune response. However, 2-arachidonoylglycerol appears to be the true endogenous ligand for peripheral cannabinoid receptors, although its action as an immunomodulatory molecule requires further characterization. Modulation of the endocannabinoid system interferes with cancer cell proliferation either by inhibiting mitogenic autocrine/paracrine loops or by directly inducing apoptosis; however, the proapoptotic effect of anandamide is not shared by other endocannabinoids and suggests the involvement of non-cannabinoid receptors, namely the VR1 class of vanilloid receptors. In conclusion, further investigations are needed to elucidate the function of endocannabinoids as immunosuppressant and antiproliferative/cytotoxic agents. The experimental evidence reviewed in this article argues in favor of the therapeutic potential of these compounds in immune disorders and cancer.
Collapse
Affiliation(s)
- Daniela Parolaro
- Department of Structural and Functional Biology, Pharmacology Unit, University of Insubria, Via A. Da Giussano 10, 21052 Busto Arsizio (Varese), Italy.
| | | | | | | |
Collapse
|
277
|
Abstract
The fatty acid amide anandamide produces hypotension and a decrease in systemic vascular resistance in vivo. A drop in blood pressure is also seen with synthetic cannabinoid (CB) receptor agonists. The hypotensive responses to anandamide and synthetic cannabinoids are absent in CB1 receptor gene knockout mice. In isolated arteries and perfused vascular beds, anandamide induces vasodilator responses, which cannot be mimicked by synthetic cannabinoids. Instead, vanilloid receptors on perivascular sensory nerves play a key role in these effects of anandamide. Activation of vanilloid receptors by anandamide triggers the release of sensory neuropeptides such as the vasodilator calcitonin gene-related peptide (CGRP). Anandamide is detected in blood and in many cells of the cardiovascular system, and macrophage-derived anandamide may be involved in several hypotensive clinical conditions. Interestingly, cannabinoid and vanilloid receptors display an overlap in ligand recognition properties, and the frequently used CB1 receptor antagonist SR141716A also inhibits vanilloid receptor-mediated responses. The presence of anandamide in endothelial cells, neurones and activated macrophages (monocytes), and its ability to activate CB and vanilloid receptors make this lipid a potential bioregulator in the cardiovascular system.
Collapse
Affiliation(s)
- Edward D Högestätt
- Department of Clinical Pharmacology, Institute of Laboratory Medicine, Lund University Hospital, SE-221 85 Lund, Sweden.
| | | |
Collapse
|
278
|
Savinainen JR, Järvinen T, Laine K, Laitinen JT. Despite substantial degradation, 2-arachidonoylglycerol is a potent full efficacy agonist mediating CB(1) receptor-dependent G-protein activation in rat cerebellar membranes. Br J Pharmacol 2001; 134:664-72. [PMID: 11588122 PMCID: PMC1572991 DOI: 10.1038/sj.bjp.0704297] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Two endocannabinoids, arachidonoyl ethanolamide (AEA) and 2-arachidonoylglycerol (2-AG) bind and activate G-protein-coupled cannabinoid receptors, but limited data exist on their relative ability to activate G-proteins. 2. Here we assess agonist potency and efficacy of various cannabinoids, including 2-AG, HU-310 (2-arachidonoyl glyceryl ether, a third putative endocannabinoid), HU-313 (another ether analogue of 2-AG), AEA, R-methanandamide (an enzymatically stable analogue of AEA), and CP-55,940 at rat brain CB(1) receptors using agonist-stimulated [(35)S]-GTPgammaS binding to cerebellar membranes and whole brain sections. Degradation of endocannabinoids under experimental conditions was monitored by HPLC. 3. To enhance efficacy differences, agonist dose-response curves were generated using increasing GDP concentrations. At 10(-6) M GDP, all compounds, except HU-313, produced full agonists responses approximately 2.5 fold over basal. The superior efficacy of 2-AG over all other compounds became evident by increasing GDP (10(-5) and 10(-4) M). 4. In membrane incubations, 2-AG was degraded by 85% whereas AEA and HU-310 were stable. Pretreatment of membranes with phenylmethylsulphonyl fluoride inhibited 2-AG degradation, resulting in 2 fold increase in agonist potency. Such pretreatment had no effect on AEA potency. 5. Responses in brain sections were otherwise consistent with membrane binding data, but 2-AG evoked only a weak signal in brain sections, apparently due to more extensive degradation. 6. These data establish that even under conditions of substantial degradation, 2-AG is a full efficacy agonist, clearly more potent than AEA, in mediating CB(1) receptor-dependent G-protein activity in native membranes.
Collapse
|
279
|
Tanaka T, Morishige J, Takimoto T, Takai Y, Satouchi K. Metabolic characterization of sciadonic acid (5c,11c,14c-eicosatrienoic acid) as an effective substitute for arachidonate of phosphatidylinositol. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:4928-39. [PMID: 11559362 DOI: 10.1046/j.0014-2956.2001.02423.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sciadonic acid (20:3 Delta-5,11,14) is an n-6 series trienoic acid that lacks the Delta8 double bond of arachidonic acid. This fatty acid is not converted to arachidonic acid in higher animals. In this study, we characterized the metabolic behavior of sciadonic acid in the process of acylation to phospholipid of HepG2 cells. One of the characteristics of fatty acid compositions of phospholipids in sciadonic acid-supplemented cells is a higher proportion of sciadonic acid in phosphatidylinositol (PtdIns) (27.4%) than in phosphatidylethanolamine (PtdEtn) (23.2%), phosphatidylcholine (PtdCho) (17.3%) and phosphatidylserine (PtdSer) (20.1%). Similarly, the proportion of arachidonic acid was higher in PtdIns (35.8%) than in PtdEtn (29.1%), PtdSer (18.2%) and PtdCho (20.2%) in arachidonic-acid-supplemented cells. The extensive accumulation of sciadonic acid in PtdIns resulted in the enrichment of newly formed 1-stearoyl-2-sciadonoyl molecular species (38%) in PtdIns and caused the reduction in the level of pre-existing arachidonic-acid-containing molecular species. The kinetics of incorporation of sciadonic acid to PtdEtn, PtdSer and PtdIns of cells were similar to those of arachidonic acid. In contrast to sciadonic acid, neither eicosapentaenoic acid (20:5 Delta-5,8,11,14,17) nor juniperonic acid (20:4 Delta-5,11,14,17) accumulated in the PtdIns fraction. Rather, these n-3 series polyunsaturated fatty acids, once incorporated into PtdIns, tended to be excluded from PtdIns. In addition, the level of arachidonic-acid-containing PtdIns molecular species remained unchanged by eicosapentaenoic-acid-supplementation. These results suggest that sciadonic acid or sciadonic-acid-containing glycerides are metabolized in a similar manner to arachidonic acid or arachidonic-acid-containing glyceride in the biosynthesis of PtdIns and that sciadonic acid can effectively modify the molecular species composition of PtdIns in HepG2 cells. In this regard, sciadonic acid will be an interesting experimental tool to clarify the significance of arachidonic acid-residue of PtdIns-origin bioactive lipids.
Collapse
Affiliation(s)
- T Tanaka
- Department of Applied Biological Science, Fukuyama University, Japan
| | | | | | | | | |
Collapse
|
280
|
Suhara Y, Nakane S, Arai S, Takayama H, Waku K, Ishima Y, Sugiura T. Synthesis and biological activities of novel structural analogues of 2-arachidonoylglycerol, an endogenous cannabinoid receptor ligand. Bioorg Med Chem Lett 2001; 11:1985-8. [PMID: 11454463 DOI: 10.1016/s0960-894x(01)00350-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Novel analogues of 2-arachidonoylglycerol (2-AG), an endogenous cannabinoid receptor ligand, were developed. Chemical synthesis of these analogues (2-AGA105 and 2-AGA109) was accomplished starting from 2-octyn-1-ol and diethyl malonate and employing Wittig coupling of triene phosphonate with an aldehyde intermediate in a convergent and stereoselective manner. These analogues should be useful lead compounds for the development of novel 2-AG mimetics.
Collapse
Affiliation(s)
- Y Suhara
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, 199-0195, Kanagawa, Japan
| | | | | | | | | | | | | |
Collapse
|
281
|
Jonsson KO, Vandevoorde S, Lambert DM, Tiger G, Fowler CJ. Effects of homologues and analogues of palmitoylethanolamide upon the inactivation of the endocannabinoid anandamide. Br J Pharmacol 2001; 133:1263-75. [PMID: 11498512 PMCID: PMC1621151 DOI: 10.1038/sj.bjp.0704199] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The ability of a series of homologues and analogues of palmitoylethanolamide to inhibit the uptake and fatty acid amidohydrolase (FAAH)-catalysed hydrolysis of [(3)H]-anandamide ([(3)H]-AEA) has been investigated. 2. Palmitoylethanolamide and homologues with chain lengths from 12 - 18 carbon atoms inhibited rat brain [(3)H]-AEA metabolism with pI(50) values of approximately 5. Homologues with chain lengths < or = eight carbon atoms gave < 20% inhibition at 100 microM. 3. R-palmitoyl-(2-methyl)ethanolamide, palmitoylisopropylamide and oleoylethanolamide inhibited [(3)H]-AEA metabolism with pI(50) values of 5.39 (competitive inhibition), 4.89 (mixed type inhibition) and 5.33 (mixed type inhibition), respectively. 4. With the exception of oleoylethanolamide, the compounds did not produce dramatic inhibition of [(3)H]-WIN 55,212-2 binding to human CB(2) receptors expressed on CHO cells. Palmitoylethanolamide, palmitoylisopropylamide and R-palmitoyl-(2-methyl)ethanolamide had modest effects upon [(3)H]-CP 55,940 binding to human CB(1) receptors expressed on CHO cells. 5. Most of the compounds had little effect upon the uptake of [(3)H]-AEA into C6 and/or RBL-2H3 cells. However, palmitoylcyclohexamide (100 microM) and palmitoylisopropylamide (30 and 100 microM) produced more inhibition of [(3)H]-AEA uptake than expected to result from inhibition of [(3)H]-AEA metabolism alone. 6. In intact C6 cells, palmitoylisopropylamide and oleoylethanolamide inhibited formation of [(3)H]-ethanolamine from [(3)H]-AEA to a similar extent as AM404, whereas palmitoylethanolamide, palmitoylcyclohexamide and R-palmitoyl-(2-methyl)ethanolamide were less effective. 7. These data provide useful information upon the ability of palmitoylethanolamide analogues to act as 'entourage' compounds. Palmitoylisopropylamide may prove useful as a template for design of compounds that reduce the cellular accumulation and metabolism of AEA without affecting either CB(1) or CB(2) receptors.
Collapse
Affiliation(s)
- K O Jonsson
- Department of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 87 Umeå, Sweden.
| | | | | | | | | |
Collapse
|
282
|
Porter AC, Felder CC. The endocannabinoid nervous system: unique opportunities for therapeutic intervention. Pharmacol Ther 2001; 90:45-60. [PMID: 11448725 DOI: 10.1016/s0163-7258(01)00130-9] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The active principle in marijuana, Delta(9)-tetrahydrocannabinol (THC), has been shown to have wide therapeutic application for a number of important medical conditions, including pain, anxiety, glaucoma, nausea, emesis, muscle spasms, and wasting diseases. Delta(9)-THC binds to and activates two known cannabinoid receptors found in mammalian tissue, CB1 and CB2. The development of cannabinoid-based therapeutics has focused predominantly on the CB1 receptor, based on its predominant and abundant localization in the CNS. Like most of the known cannabinoid agonists, Delta(9)-THC is lipophilic and relatively nonselective for both receptor subtypes. Clinical studies show that nonselective cannabinoid agonists are relatively safe and provide therapeutic efficacy, but that they also induce psychotropic side effects. Recent studies of the biosynthesis, release, transport, and disposition of anandamide are beginning to provide an understanding of the role of lipid transmitters in the CNS. This review attempts to link current understanding of the basic biology of the endocannabinoid nervous system to novel opportunities for therapeutic intervention. This new knowledge may facilitate the development of cannabinoid receptor-targeted therapeutics with improved safety and efficacy profiles.
Collapse
Affiliation(s)
- A C Porter
- Neuroscience Division, Drop 0510, Lilly Research Laboratories, Indianapolis, IN 46285, USA
| | | |
Collapse
|
283
|
Bisogno T, MacCarrone M, De Petrocellis L, Jarrahian A, Finazzi-Agrò A, Hillard C, Di Marzo V. The uptake by cells of 2-arachidonoylglycerol, an endogenous agonist of cannabinoid receptors. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:1982-9. [PMID: 11277920 DOI: 10.1046/j.1432-1327.2001.02072.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
It is not yet clear if the endocannabinoid 2-arachidonoylglycerol (2-AG) is transported into cells through the same membrane transporter mediating the uptake of the other endogenous cannabinoid, anandamide (N-arachidonoylethanolamine, AEA), and whether this process (a) is regulated by cells and (b) limits 2-AG pharmacological actions. We have studied simultaneously the facilitated transport of [14C]AEA and [3H]2-AG into rat C6 glioma cells and found uptake mechanisms with different efficacies but similar affinities for the two compounds (Km 11.0 +/- 2.0 and 15.3 +/- 3.1 microM, Bmax 1.70 +/- 0.30 and 0.24 +/- 0.04 nmol.min-1.mg protein-1, respectively). Despite these similar Km values, 2-AG inhibits [14C]AEA uptake by cells at concentrations (Ki = 30.1 +/- 3.9 microM) significantly higher than those required to either 2-AG or AEA to inhibit [3H]2-AG uptake (Ki = 18.9 +/- 1.8 and 20.5 +/- 3.2 microM, respectively). Furthermore: (a) if C6 cells are incubated simultaneously with identical concentrations of [14C]AEA and [3H]2-AG, only the uptake of the latter compound is significantly decreased as compared to that observed with [3H]2-AG alone; (b) the uptake of [14C]AEA and [3H]2-AG by cells is inhibited with the same potency by AM404 (Ki = 7.5 +/- 0.7 and 10.2 +/- 1.7 microM, respectively) and linvanil (Ki = 9.5 +/- 0.7 and 6.4 +/- 1.2 microM, respectively), two inhibitors of the AEA membrane transporter; (c) nitric oxide (NO) donors enhance the uptake of both [14C]AEA and [3H]2-AG, thus suggesting that 2-AG action can be regulated through NO release; (d) AEA and 2-AG induce a weak release of NO that can be blocked by a CB1 cannabinoid receptor antagonist, and significantly enhanced in the presence of AM404 and linvanil, thus suggesting that transport into C6 cells limits the action of both endocannabinoids.
Collapse
Affiliation(s)
- T Bisogno
- Endocannabinoid Research Group, Istituto per la Chimica di Molecole di Interesse Biologico (VDM, TB), Arco Felice, Napoli, Italy
| | | | | | | | | | | | | |
Collapse
|
284
|
Tucker RC, Kagaya M, Page CP, Spina D. The endogenous cannabinoid agonist, anandamide stimulates sensory nerves in guinea-pig airways. Br J Pharmacol 2001; 132:1127-35. [PMID: 11226144 PMCID: PMC1572645 DOI: 10.1038/sj.bjp.0703906] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The endogenous cannabinoid agonist, anandamide produced a modest contractile response in guinea-pig isolated bronchus compared with the vanilloid receptor agonist capsaicin. The contractile response to both anandamide and capsaicin was inhibited by the vanilloid receptor antagonist, capsazepine. Furthermore, the NK(2)-selective antagonist, SR48968 but not the NK(1)-selective antagonist, SR140333 inhibited contractile responses to anandamide. The contractile response to anandamide was abolished in tissues desensitized by capsaicin. However, anandamide failed to cross-desensitize the contractile response to capsaicin. The contractile response to anandamide was not significantly altered in the presence of the CB(1) receptor antagonist, SR141716A, nor the amidase inhibitor, phenylmethylsulphonyl fluoride (PMSF) but was significantly increased in the presence of the neutral endopeptidase inhibitor, thiorphan. The cannabinoid agonist, CP55,940 failed to significantly attenuate the excitatory non-adrenergic non-cholinergic (eNANC) response in guinea-pig airways. In contrast, the ORL(1) receptor agonist, nociceptin, significantly inhibited this response. The results demonstrate that anandamide induces a modest contractile response in guinea-pig isolated bronchus that is dependent upon the activation of vanilloid receptors on airway sensory nerves. However, cannabinoid receptors do not appear to play a role in this regard, nor in regulating the release of neuropeptides from airway sensory nerves under physiological conditions.
Collapse
Affiliation(s)
- R C Tucker
- The Sackler Institute of Pulmonary Pharmacology, Division of Pharmacology and Therapeutics, GKT School of Biomedical Sciences, King's College London, Hodgkin Building, Guy's Campus, London Bridge, London SE1 9RT
| | - M Kagaya
- The Sackler Institute of Pulmonary Pharmacology, Division of Pharmacology and Therapeutics, GKT School of Biomedical Sciences, King's College London, Hodgkin Building, Guy's Campus, London Bridge, London SE1 9RT
| | - C P Page
- The Sackler Institute of Pulmonary Pharmacology, Division of Pharmacology and Therapeutics, GKT School of Biomedical Sciences, King's College London, Hodgkin Building, Guy's Campus, London Bridge, London SE1 9RT
| | - D Spina
- Department of Respiratory Medicine and Allergy, GKT School of Medicine and Dentistry, Bessemer Road, London SE5 9PJ
- Author for correspondence:
| |
Collapse
|
285
|
MacCarrone M, Bari M, Menichelli A, Giuliani E, Del Principe D, Finazzi-Agrò A. Human platelets bind and degrade 2-arachidonoylglycerol, which activates these cells through a cannabinoid receptor. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:819-25. [PMID: 11168423 DOI: 10.1046/j.1432-1327.2001.01942.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The endocannabinoid 2-arachidonoylglycerol (2-Delta(4)Ach-Gro) activates human platelets in platelet-rich plasma at physiological concentrations. The activation was inhibited by selective antagonists of CB(1) and CB(2) cannabinoid receptors, but not by acetylsalicylic acid. Human platelets can metabolize 2-Delta(4)Ach-Gro by internalization through a high affinity transporter (K(m) = 300 +/- 30 nM, V(max) = 10 +/- 1 pmol.min(-1).mg protein(-1)), followed by hydrolysis by a fatty acid amide hydrolase (K(m) = 8 +/- 1 microM, V(max) = 400 +/- 50 pmol.min(-1).mg protein(-1)). The anandamide transport inhibitor AM404, and anandamide itself, were ineffective on 2-Delta(4)Ach-Gro uptake by platelets, whereas anandamide competitively inhibited 2-Delta(4)Ach-Gro hydrolysis (inhibition constant = 10 +/- 1 microM). Platelet activation by 2-Delta(4)Ach-Gro was paralleled by an increase of intracellular calcium and inositol-1,4,5-trisphosphate, and by a decrease of cyclic AMP. Moreover, treatment of preloaded platelet-rich plasma with 2-Delta(4)Ach-Gro induced an approximately threefold increase in [(3)H]2-Delta(4)Ach-Gro release, according to a CB receptor-dependent mechanism. On the other hand, ADP and collagen counteracted the activation of platelets by 2-Delta(4)Ach-Gro, whereas 5-hydroxytryptamine (serotonin) enhanced and extended its effects. Remarkably, ADP and collagen also reduced [(3)H]2-Delta(4)Ach-Gro release from 2-Delta(4)Ach-Gro-activated platelets, whereas 5-hydroxytryptamine further increased it. These findings suggest a so far unnoticed interplay between the peripheral endocannabinoid system and physiological platelet agonists.
Collapse
Affiliation(s)
- M MacCarrone
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Italy
| | | | | | | | | | | |
Collapse
|
286
|
Moody JS, Kozak KR, Ji C, Marnett LJ. Selective oxygenation of the endocannabinoid 2-arachidonylglycerol by leukocyte-type 12-lipoxygenase. Biochemistry 2001; 40:861-6. [PMID: 11170406 DOI: 10.1021/bi002303b] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The endogenous cannabinoid system appears to serve vascular, neurological, immunological, and reproductive functions. The identification of 2-arachidonylglycerol (2-AG) as an endogenous ligand for the central (CB1) and peripheral (CB2) cannabinoid receptors has prompted interest in enzymes capable of modifying or inactivating this endocannabinoid. Porcine leukocyte 12-liopoxygenase (12-LOX) oxygenated 2-AG to the 2-glyceryl ester of 12(S)-hydroperoxyeicosa-5,8,10,14-tetraenoic acid (12-HPETE-G). The k(cat)/K(M) for oxygenation of 2-AG was 40% of the value for arachidonic acid. In contrast to the results with leukocyte 12-LOX, 2-AG oxygenation was not detected with platelet-type 12-LOX. Among a series of structurally related arachidonyl esters, 2-AG served as the preferential substrate for leukocyte 12-LOX. 12(S)-Hydroxyeicosa-5,8,10,14-tetraenoic acid glyceryl ester (12-HETE-G) was produced following addition of 2-AG to COS-7 cells transiently transfected with leukocyte 12-LOX. These results demonstrate that leukocyte-type 12-LOX efficiently oxidizes 2-AG in vitro and in intact cells, suggesting a role for this oxygenase in the endogenous cannabinoid system.
Collapse
Affiliation(s)
- J S Moody
- Department of Biochemistry, Vanderbilt-Ingram Cancer Center and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | | | | | | |
Collapse
|
287
|
Sugiura T, Yoshinaga N, Waku K. Rapid generation of 2-arachidonoylglycerol, an endogenous cannabinoid receptor ligand, in rat brain after decapitation. Neurosci Lett 2001; 297:175-8. [PMID: 11137756 DOI: 10.1016/s0304-3940(00)01691-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rat brain, frozen in liquid nitrogen immediately after decapitation, contains a substantial amount of 2-arachidonoylglycerol (0.34 nmol/g tissue), an endogenous cannabinoid receptor ligand. The level of 2-arachidonoylglycerol in the brain was rapidly augmented after decapitation, the peak being noted 30 s after decapitation (1.54 nmol/g tissue). Noticeably, there are two phases during the increase in the levels of 2-arachidonoylglycerol: a rapid transient increase and a subsequent gradual sustained increase, suggesting that at least two separate mechanisms are involved in the generation of 2-arachidonoylglycerol in the decapitated brain. Gradual sustained formation was also observed for other monoacylglycerols, (e.g. 2-palmitoylglycerol plus 2-oleoylglycerol and 2-cis-vaccenoylglycerol). Thus, it is important to minimize post-mortem changes to estimate the exact tissue levels of 2-arachidonoylglycerol as well as other monoacylglycerols in the brain.
Collapse
Affiliation(s)
- T Sugiura
- Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Tsukui-gun, 199-0195, Kanagawa, Japan.
| | | | | |
Collapse
|
288
|
|
289
|
Di Marzo V, Breivogel CS, Tao Q, Bridgen DT, Razdan RK, Zimmer AM, Zimmer A, Martin BR. Levels, metabolism, and pharmacological activity of anandamide in CB(1) cannabinoid receptor knockout mice: evidence for non-CB(1), non-CB(2) receptor-mediated actions of anandamide in mouse brain. J Neurochem 2000; 75:2434-44. [PMID: 11080195 DOI: 10.1046/j.1471-4159.2000.0752434.x] [Citation(s) in RCA: 273] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Anandamide [arachidonylethanolamide (AEA)] appears to be an endogenous agonist of brain cannabinoid receptors (CB(1)), yet some of the neurobehavioral effects of this compound in mice are unaffected by a selective CB(1) antagonist. We studied the levels, pharmacological actions, and degradation of AEA in transgenic mice lacking the CB(1) gene. We quantified AEA and the other endocannabinoid, 2-arachidonoyl glycerol, in six brain regions and the spinal cord by isotope-dilution liquid chromatography-mass spectrometry. The distribution of endocannabinoids and their inactivating enzyme, fatty acid amide hydrolase, were found to overlap with CB(1) distribution only in part. In CB(1) knockout homozygotes (CB(1)-/-), the hippocampus and, to a lesser extent, the striatum exhibited lower AEA levels as compared with wild-type (CB(1)+/+) controls. These data suggest a ligand/receptor relationship between AEA and CB(1) in these two brain regions, where tonic activation of the receptor may tightly regulate the biosynthesis of its endogenous ligand. 2-Arachidonoyl glycerol levels and fatty acid amide hydrolase activity were unchanged in CB(1)-/- with respect to CB(1)+/+ mice in all regions. AEA and Delta(9)-tetrahydrocannabinol (THC) were tested in CB(1)-/- mice for their capability of inducing analgesia and catalepsy and decreasing spontaneous activity. The effects of AEA, unlike THC, were not decreased in CB(1)-/- mice. AEA, but not THC, stimulated GTPgammaS binding in brain membranes from CB(1)-/- mice, and this stimulation was insensitive to CB(1) and CB(2) antagonists. We suggest that non-CB(1), non-CB(2) G protein-coupled receptors might mediate in mice some of the neuro-behavioral actions of AEA.
Collapse
Affiliation(s)
- V Di Marzo
- Istituto per la Chimica di Molecole di Interesse Biologico, Consiglio Nazionale delle Ricerche, Arco Felice, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
290
|
Abstract
2-Arachidonoylglycerol (2-AG) is a unique molecular species of monoacylglycerol isolated from rat brain and canine gut as an endogenous cannabinoid receptor ligand (Sugiura, T., Kondo, S., Sukagawa, A., Nakane, S., Shinoda, A., Itoh, K., Yamashita, A., Waku, K., 1995. 2-Arachidonoylglycerol: a possible endogenous cannabinoid receptor ligand in brain. Biochem. Biophys. Res. Commun. 215, 89-97; Mechoulam, R., Ben-Shabat, S., Hanus, L., Ligumsky, M., Kaminski, N. E., Schatz, A.R., Gopher, A., Almog, S., Martin, B.R., Compton, D.R., Pertwee, R.G., Giffin, G., Bayewitch, M., Brag, J., Vogel, Z., 1995. Identification of an endogenous 2-monoglyceride, present in canine gut, that binds to cannabinoid receptors. Biochem. Pharmacol. 50, 83-90). 2-AG binds to the cannabinoid receptors (CB1 and CB2) and exhibits a variety of cannabimimetic activities in vitro and in vivo. Recently, we found that 2-AG induces Ca(2+) transients in NG108-15 cells, which express the CB1 receptor, and in HL-60 cells, which express the CB2 receptor, through a cannabinoid receptor- and Gi/Go-dependent mechanism. Based on the results of structure-activity relationship experiments, we concluded that 2-AG but not anandamide is the natural ligand for both the CB1 and the CB2 receptors and both receptors are primarily 2-AG receptors. Evidences are gradually accumulating that 2-AG is a physiologically essential molecule, although further detailed studies appear to be necessary to determine relative importance of 2-AG and anandamide in various animal tissues. In this review, we described mainly our previous and current experimental results, as well as those of others, concerning the tissue levels, bioactions and metabolism of 2-AG.
Collapse
Affiliation(s)
- T Sugiura
- Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Tsukui-gun, 199-0195, Kanagawa, Japan.
| | | |
Collapse
|
291
|
Abstract
Cannabinoid research underwent a tremendous increase during the last 10 years. This progress was made possible by the discovery of cannabinoid receptors and the endogenous ligands for these receptors. Cannabinoid research is developing in two major directions: neurobehavioral properties of cannabinoids and the impact of cannabinoids on the immune system. Recent studies characterized the cannabinoid-induced response as a very complex process because of the involvement of multiple signalling pathways linked to cannabinoid receptors or effects elicited by cannabinoids without receptor participation. The objective of this review is to present this complexity as it applies to immune response. The functional properties of cannabinoid receptors, signalling pathways linked to cannabinoid receptors and the modulation of immune response by cannabinoid receptor ligands are discussed. Special attention is given to 'endocannabinoids' as immunomodulatory molecules.
Collapse
Affiliation(s)
- E V Berdyshev
- The Hormel Institute, University of Minnesota, 801 16th Avenue N.E., Austin, MN 55912, USA.
| |
Collapse
|
292
|
Schmid HH. Pathways and mechanisms of N-acylethanolamine biosynthesis: can anandamide be generated selectively? Chem Phys Lipids 2000; 108:71-87. [PMID: 11106783 DOI: 10.1016/s0009-3084(00)00188-2] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Long-chain N-acylethanolamines (NAEs) and their precursors, N-acylethanolamine phospholipids, are ubiquitous trace constituents of animal and human cells, tissues and body fluids. Their cellular levels appear to be tightly regulated and they accumulate as the result of injury. Saturated and monounsaturated congeners which represent the vast majority of cellular NAEs can have cytoprotective effects while polyunsaturated NAEs, especially 20:4n-6 NAE (anandamide), elicit physiological effects by binding to and activating cannabinoid receptors. It is the purpose of this article to review published data on the pathways and mechanisms of NAE biosynthesis in mammals and to evaluate this information for its physiological significance. The generation and turnover of NAE via N-acyl PE through the transacylation-phosphodiesterase pathway may represent a novel cannabinoid receptor-independent signalling system, analogous to and possibly related to ceramide-mediated cell signalling.
Collapse
Affiliation(s)
- H H Schmid
- The Hormel Institute, University of Minnesota, 801 16th Ave NE, Austin, MN 55912, USA.
| |
Collapse
|
293
|
Kozak KR, Rowlinson SW, Marnett LJ. Oxygenation of the endocannabinoid, 2-arachidonylglycerol, to glyceryl prostaglandins by cyclooxygenase-2. J Biol Chem 2000; 275:33744-9. [PMID: 10931854 DOI: 10.1074/jbc.m007088200] [Citation(s) in RCA: 325] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclooxygenases (COX) play an important role in lipid signaling by oxygenating arachidonic acid to endoperoxide precursors of prostaglandins and thromboxane. Two cyclooxygenases exist which differ in tissue distribution and regulation but otherwise carry out identical chemical functions. The neutral arachidonate derivative, 2-arachidonylglycerol (2-AG), is one of two described endocannabinoids and appears to be a ligand for both the central (CB1) and peripheral (CB2) cannabinoid receptors. Here we report that 2-AG is a substrate for COX-2 and that it is metabolized as effectively as arachidonic acid. COX-2-mediated 2-AG oxygenation provides the novel lipid, prostaglandin H(2) glycerol ester (PGH(2)-G), in vitro and in cultured macrophages. PGH(2)-G produced by macrophages is a substrate for cellular PGD synthase, affording PGD(2)-G. Pharmacological studies reveal that macrophage production of PGD(2)-G from endogenous sources of 2-AG is calcium-dependent and mediated by diacylglycerol lipase and COX-2. These results identify a distinct function for COX-2 in endocannabinoid metabolism and in the generation of a new family of prostaglandins derived from diacylglycerol and 2-AG.
Collapse
Affiliation(s)
- K R Kozak
- Departments of Biochemistry and Chemistry, Vanderbilt-Ingram Cancer Center and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | | | | |
Collapse
|
294
|
Sugiura T, Yoshinaga N, Kondo S, Waku K, Ishima Y. Generation of 2-arachidonoylglycerol, an endogenous cannabinoid receptor ligand, in picrotoxinin-administered rat brain. Biochem Biophys Res Commun 2000; 271:654-8. [PMID: 10814517 DOI: 10.1006/bbrc.2000.2686] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The levels of 2-arachidonoylglycerol, an endogenous cannabinoid receptor ligand, and other molecular species of monoacylglycerols in rat brain were examined. In this study, we sacrificed the animals in liquid nitrogen to minimize postmortem changes. We found that rat brain contains 0.23 nmol/g tissue of 2-arachidonoylglycerol, which accounts for 10.5% of the total monoacylglycerol present in this tissue. We next investigated the level of 2-arachidonoylglycerol after in vivo stimulation with picrotoxinin. We found that the level of 2-arachidonoylglycerol was elevated markedly in picrotoxinin-administered rat brain (4- to 6-fold over the control level). Changes in the levels of other molecular species were relatively small or negligible. Several cannabimimetic molecules as well as Delta(9)-tetrahydrocannabinol are known to depress neurotransmission and to exert anticonvulsant activities; endogenous 2-arachidonoylglycerol produced during neural excitation may play a regulatory role in calming the enhanced synaptic transmission.
Collapse
Affiliation(s)
- T Sugiura
- Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, 199-0195, Japan
| | | | | | | | | |
Collapse
|