Arachidonoyl-ethanolamine

One such amide present in chocolate is anandamide (N-arachidonoyl-ethanolamine). Anandamide, together with N-oleylethanolamine and N-linoleylethanolamine, bind to a receptor. In the brain which also binds tetrahydrocannabinol, the psychoactive compound in cannabis. Could this explain the addiction ... 

A compound with the same molecular weight as anandamide, but with a shorter retention time, was identified as O-arachidonoyl ethanolamine (arachidonic acid and ethanolamine joined by an ester linkage) (EC50 = 1906 nM). Based on this opposite orientation, the molecule was named virodhamine from the Sanskrit word, virodha, which means opposition. 

Fig. 1. Hemodynamic effects of anandamide in anesthetized mice. Representative recordings ofthe effects of anandamide [20 mg/kg i.v., W-arachidonoyl-ethanolamine (/1 4)] on mean arterial pressure (iW/iP, top panel, cardiac contractility (left ventricular systolic pressure LVSP and dP/df (dPdt) middle panel and pressure-volume relations (bottom panel in a pentobarbital-anesthetized C57BL6 mouse. The five parts of the and bottom panels represent baseline conditions (BI, phase I (/), phase II (//), and phase III (III ofthe anandamide response, and recovery 10 min following the injection. The arrow indicates the injection ofthe drug. The decrease ofthe amplitude of PV loops and shift to the right indicate decrease of cardiac contractile performance...

Lynch DL and Reggio PH (2005) Molecular dynamics simulations of the endocannabinoid N-arachidonoyl-ethanolamine (anandamide) in a phospholipid bilayer probing structure and dynamics. J Med Chem 48 4824-4833. 

The mammalian endocannabinoid family inclndes fonr lipid Af-fatty acyl-ethanolamines (NAEs), two Af-acyl-dopamines, a lipid ester, and a lipid ether. The NAEs are Af-arachidonoyl ethanolamine (anan-damide, AEA) (Devane et al., 1992), docosatetraenoyl-ethanolamide and di-homo-y-hnolenoyl-ethanolamide (Hanus et al., 1993), and O-arachidonoyl ethanolamide (virodhamine) (Porter et al., 2002). The Af-acyl-dopamines are Af-arachidonoyl-dopamine (NADA) and Af-oleoyl-dopamine (Hnang et al., 2002). The lipid ester is sn-2 arachidonoyl glycerol (2-AG) (Mechonlam et al., 1995 Sugiura et al., 1995). The lipid ether is sn-2 arachidonoyl glyceryl ether (noladin ether) (Hanus et al., 2001). 

Anandamide is believed to be synthesized from a phospholipid precursor, /V-arachidonoyl-phosphatidylethanolamine, catalysed by phospholipase D (Di Marzo et al. 1998). The other proposed route of synthesis is from condensation of arachidonic acid and ethanolamine, although this has yet to be demonstrated in living cells. 2-AG is formed in a calcium-dependent manner, and mediated by the enzymes phospholipase C and diacylglycerol lipase (Kondo et al. 1998 Stella et al. 1997). 

Burstein and Hunter (1995) observed that THC stimulated the biosynthesis of anandamide in neuroblastoma cells employing either ethanolamine or arachidonic acid as the label. Anandamide bios5mthesis has also been shown to occur in primary cultures of rat brain neurons labelled with [H]-ethanolamine when stimulated with ionomycin, a Ca ionophore (Di Marzo et al. 1994). These authors proposed an alternate model for the biosynthesis of anandamide in which N-arachidonoyl phosphatidyl ethanolamine is cleaved by a phospholipase D activity to yield phosphatidic acid and ararchidonoylethanolamide. This model is based upon extensive studies undertaken by Schmid and collaborators (1990), who have shown that fatty acid ethanolamide formation results from the N-acylation of phosphatidyl ethanolamine by a transacylase to form N-acyl phosphatidylethanolamine. Possibly resulting from postmortem changes, this compound is subsequently hydrolyzed to the fatty acid ethanolamide and the corresponding phosphatide by a phosphodiesterase, phospholipase D. 

Acylation of Phospholipids - The esterification of long-chain, unsaturated fatty acids in the sn-2-position could be explained by different enzyme activities such as specific long-chain acyl-CoA synthetases and CoA-dependent or CoA-independent transacylases.6-11 For example, a long-chain acyl-CoA synthetase has been demonstrated in Isolated platelet membranes that is specific for arachidonate and other long-chain unsaturated fatty acids.6,7 Transfer of arachidonic acid between phospholipids has been observed by the action of CoA-dependent and CoA-independent transacylases. The CoA-dependent transacylases were demonstrated in lymphocytes,8 pancreatic acini9 and liver microsomes.10 A CoA-independent transacylase, recently observed in platelets, catalyzes the synthesis of arachidonoyl-plasmenyl-ethanolamine by acylation of lysoplasmenylethanolamine with arachidonic acid derived from phosphatidylcholine. 1... 

Sugiura, T., Kondo, S., Sukagawa, A., Tonegawa, T., Nakane, S., Yamashita, A., Ishima, Y., and Waku, K. (1996). Transacylase-mediated and phosphodiesterase-mediated synthesis of iV-arachidonoyle-thanolamine, an endogenous cannabinoid-receptor ligand, in rat brain microsomes — comparison with synthesis from free arachidonic acid and ethanolamine. Eur. J. Biochem. 240, 53-62. 

Cadas, H., di Tomaso, E., Piomelli, D., 1997. Occurrence and biosynthesis of endogenous cannabinoid precursor, iV-arachidonoyl phosphatidyl-ethanolamine, in rat brain. J. Neurosci. 17, 1226-1242. 

The discovery of anandamide (arachidonoyl ethanolamide, AEA) and of its manifold roles in the central nervous system and in the periphery (reviewed in refs. 1 and 2) prompted several researchers to develop analytical methods to assay and characterize the activity of the enzymes responsible for AEA metabolism in various cells and tissues. Fatty acid amide hydrolase (arachidonoyl ethanolamide amidohydrolase, EC 3.5.1.4 FAAH) has emerged as the key AEA hydrolase, showing a molecular mass of approx 64 kDa and an optimum pH of around 9.0 (3). Recently, FAAH has been crystallized,and its three dimensional structure has been determined at 2.8A resolution (4). This enzyme cleaves the amide bond and releases arachidonic acid and ethanolamine. High-performance liquid chromatography (HPLC) is the most widely used method to determine FAAH activity from different sources. We developed a new method (5) based on reversed-phase (RP)-HPLC and on-line scintillation counting, which combines the need for high resolution, reproducibility, and sensitivity... 

The presence of CB receptors implies the existence of endogenous ligands. The first member of this family of neuromodulator lipids, collectively indicated as endocannabinoids, has been discovered in 1992 by Mechoulam and Devane [33], identified as A -arachidonylethanolamine and called anandamide (23). Endocannabinoids are amide (e.g., anandamide), ester (e.g., 2-arachidonoyl glycerol, 24) [34], or ether (e.g., noladin) derivatives of arachidonic acid with small molecules, such as ethanolamine or glycerol. 

FIGURE 5.10 Chemical structure of anandamide. Three models of anandamide (arachidonoyl ethanolamide, AEA) are shown. In the first one (on the top) the region inherited from arachidonic acid (C20 4(o6) is framed. Note the four-double bonds in the cis (Z) configuration (see Chapter 1 for a description of unsaturated fatty acids). The ethanolamine part is shaded in rose. The two other models show an energy-minimized structure of anandamide in tube and sphere rendition. The arrows indicate the correspondence of chemical groups between the models. 

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