glycerophospho-n-arachidonoyl ethanolamine

N-Acylated ethanolamines (NAE) are naturally-occurring lipids that have diverse bioactivities. The different types of NAE can be derived from glycerophospho-linked precursors by the activity of glycerophosphodiesterase 1 (GDE1). Glycerophospho-N-arachidonoyl ethanolamine is the precursor of arachidonoyl ethanolamide (AEA), also known as anandamide. AEA is an endogenous cannabinoid neurotransmitter that binds to both central cannabinoid (CB1) and peripheral cannabinoid (CB2) receptors. It inhibits the specific binding of [3H]-HU-243 to synaptosomal membranes with a Ki value of 52 nM, compared to 46 nM for δ9-THC.

N-Acylated ethanolamines (NAE) are naturally-occurring lipids that have diverse bioactivities. For example, arachidonoyl ethanolamide (AEA) is an endogenous neurotransmitter that evokes cellular responses by activating the cannabinoid receptors, central cannabinoid (CB1) and peripheral cannabinoid (CB2). The different types of NAE are derived from glycerophospho-linked precursors by the activity of glycerophosphodiesterase 1 (GDE1). Glycerophospho-N-palmitoyl ethanolamine (GP-NPEA) is the metabolic precursor of palmitoyl ethanolamide (PEA). PEA is an endogenous cannabinoid found in brain, liver, and other mammalian tissues, that has potent anti-inflammatory activity in vivo. PEA has low affinity for peripheral cannabinoid (CB2) and no appreciable affinity for central cannabinoid (CB1), suggesting that its efficacy is through a different receptor.

Several different arachidonoyl amino acids, including N-arachidonoyl-3-hydroxy-γ-aminobutyric acid (NAG-3H-ABA), have been isolated and characterized from bovine brain. The glycine congener was further characterized and found to suppress formalin-induced pain in rats. NAG-3H-ABA was also found in rat brain by LC-MS techniques, but has not been fully characterized to date. Most arachidonoyl amino acids are poor ligands for the CB1 receptor.

Several different arachidonoyl amino acids, including N-arachidonoyl-L-alanine (NALA), have been isolated and characterized from bovine brain. The glycine congener (NAGly) was further characterized and found to suppress formalin-induced pain in rats. NALA may have activity at cannabinoid receptor and/or VR1, but has not been fully characterized to date.

N-Arachidonoyl-L-serine (ARA-S), a recently isolated endocannabinoid with a distinct activity profile that diverges from typical endocannabinoids, does not interact with central cannabinoid (CB1), peripheral cannabinoid (CB2) receptors, or vanilloid receptor 1 (VR1). Unlike other compounds, ARA-S (5 mg/kg) counteracts the lowering of blood pressure induced by a 10 mg/kg intravenous bolus of abnormal cannabidiol (Abn-CBD) in anesthetized rat models. Additionally, akin to Abn-CBD, ARA-S induces relaxation in isolated rat mesenteric arteries and abdominal aorta and promotes phosphorylation of Akt and mitogen-activated protein kinase (MAPK) in human umbilical vein endothelial cells (HUVEC). The mechanisms through which ARA-S and Abn-CBD exert their effects on vascular systems show variations and merit deeper investigation.

N-Arachidonoyl taurine is an arachidonoyl amino acid. It is oxygenated by 12(S)- and 15(S)-lipoxygenase and is converted to 12-HETE-taurine (12-HETE-T) in murine resident peritoneal macrophages. N-Arachidonoyl taurine is an activator of the transient receptor potential vanilloid (TRPV) channels TRPV1 and TRPV4 (EC50s = 28 and 21 μM, respectively). It increases calcium flux in HIT-T15 pancreatic β-cells and INS-1 rat islet cells when used at a concentration of 10 μM and increases insulin secretion from 832/13 INS-1 pancreatic β-cells. The levels of N-arachidonoyl taurine are changed in mouse brain following administration of δ9-tetrahydrocannabinol (δ9-THC).

Anandamide (AEA), an endogenous cannabinoid, interacts with both central (CB1) and peripheral (CB2) cannabinoid receptors. Its effects are concluded through the cellular uptake and enzymatic breakdown of its amide bond by fatty acid amide hydrolase. Arachidonoyl-N-methyl amide, an analog of anandamide, specifically targets the human CB1 receptor, displaying a binding affinity with a Ki of 60 nM. It completely inhibits rat glial gap junction intercellular communication at a concentration of 50 µM.