Names | |
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Preferred IUPAC name (5Z,8Z,11Z,14Z)-N-(2-hydroxyethyl)icosa-5,8,11,14-tetraenamide | |
Other names N-arachidonoylethanolamine arachidonoylethanolamide | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
KEGG | |
MeSH | Anandamide |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C22H37NO2 | |
Molar mass | 347.53 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Anandamide (ANA), also referred to as N-arachidonoylethanolamine (AEA) is a fatty acid neurotransmitter belonging to the fatty acid derivative group known as N-acylethanolamine (NAE). Anandamide takes its name from the Sanskrit word ananda, meaning "joy, bliss, delight," plus amide. Anandamide, the first discovered endocannabinoid, engages with the body's endocannabinoid system by binding to the same cannabinoid receptors that THC found in cannabis acts on. Anandamide can be found within tissues in a wide range of animals. [1] [2] It has also been found in plants, such as the cacao tree. [3]
Anandamide is derived from the non-oxidative metabolism of arachidonic acid, an essential omega-6 fatty acid. It is synthesized from N-arachidonoyl phosphatidylethanolamine by multiple pathways. [4] It is degraded primarily by the fatty acid amide hydrolase (FAAH) enzyme, which converts anandamide into ethanolamine and arachidonic acid. As such, inhibitors of FAAH lead to elevated anandamide levels and are being pursued for possible therapeutic use. [5] [6]
Anandamide was discovered by Raphael Mechoulam and fellow coworkers in 1992. This was the first marijuana-like substance produced by the human body to be observed. By examining a pig brain and canine gut, they were able to isolate ANA using mass spectrometry and nuclear magnetic resonance spectroscopy. [7] ANA works within the system of the brain associated with the feeling of reward, and as such, has been the topic of many research studies. [8] Since the 1992 findings, many studies have been completed to examine ANA further, including research on behavioral and molecular effects.
This section needs to be updated.(July 2024) |
According to in vitro research, anandamide effects are mediated primarily by CB1 cannabinoid receptors in the central nervous system, and CB2 cannabinoid receptors in the periphery. [9] The latter appear to be involved in functions of the immune system. Cannabinoid receptors were originally discovered as sensitive to Δ9-tetrahydrocannabinol (Δ9-THC, commonly called THC), which is the primary psychoactive cannabinoid found in cannabis. The discovery of anandamide came from research into CB1 and CB2, as it was inevitable that a naturally occurring (endogenous) chemical would be found to affect these receptors.
Anandamide is under research for its potential involvement in the implantation of the early stage embryo in its blastocyst form into the uterus. Therefore, cannabinoids such as Δ9-THC might influence processes during the earliest stages of human pregnancy. [10] Peak plasma anandamide occurs at ovulation and positively correlates with peak estradiol and gonadotrophin levels, suggesting that these may be involved in the regulation of anandamide levels. [11] Subsequently, anandamide has been proposed as a biomarker of infertility, but so far lacks any predictive values in order to be used clinically. [12]
Both the CB1 and CB2 receptors (the binding site of anandamide) are under research for a possible role in positive and negative interpretation of environment and setting. [13] The binding relationship of anandamide and the CB1/CB2 may affect neurotransmission of dopamine, serotonin, GABA, and glutamate. [14]
Endocannabinoids may disturb homeostasis in several ways: by enhancing hunger sensations, encouraging increased food intake, and shifting energy balance towards energy storage. A resultant decrease in energy expenditure is observed. [15]
Cortical glutamatergic transmission may be modulated by endocannabinoids during stress and fear habituation. [16]
Blockade of CB1 receptors was found to improve lipid resistance and lipid profile in obese subjects with type 2 diabetes. [17] Elevated anandamide levels are found in people with nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, and liver fibrosis. [18]
The American Academy of Dermatology has named topical anandamide a promising therapy for cutaneous lupus erythematosus. [19] [20]
In humans, anandamide is biosynthesized from N-arachidonoyl phosphatidylethanolamine (NAPE). In turn, NAPE arises by transfer of arachidonic acid from lecithin to the free amine of cephalin through an N-acyltransferase enzyme. [21] [22] Anandamide synthesis from NAPE occurs via multiple pathways and includes enzymes such as phospholipase A2, phospholipase C and N-acetylphosphatidylethanolamine-hydrolysing phospholipase D (NAPE-PLD), [4] with other key enzymes yet to be identified. [23]
The crystal structure of NAPE-PLD in complex with phosphatidylethanolamine and deoxycholate shows how the cannabinoid anandamide is generated from membrane N-acylphosphatidylethanolamines (NAPEs), and reveals that bile acids – which are mainly involved in the absorption of lipids in the small intestine – modulate its biogenesis. [24]
Endogenous anandamide is present at very low levels and has a very short half-life due to the action of the enzyme fatty acid amide hydrolase (FAAH), which breaks it down into free arachidonic acid and ethanolamine. Studies of piglets show that dietary levels of arachidonic acid and other essential fatty acids affect the levels of anandamide and other endocannabinoids in the brain. [25] High fat diet feeding in mice increases levels of anandamide in the liver and increases lipogenesis. [26] Anandamide may be relevant to the development of obesity, at least in rodents.
Paracetamol (known as acetaminophen in the US and Canada) is metabolically combined with arachidonic acid by FAAH to form AM404. [27] This metabolite is a potent agonist at the TRPV1 vanilloid receptor, a weak agonist at both CB1 and CB2 receptors, and an inhibitor of anandamide reuptake. Consequently, anandamide levels in the body and brain are elevated. Thus, paracetamol acts as a pro-drug for a cannabimimetic metabolite, which may be partially or fully responsible for its analgesic effects. [28] [29]
Black pepper contains the alkaloid guineesine, which is an anandamide reuptake inhibitor. It may therefore increase anandamide's physiological effects. [30]
Endocannabinoid transporters for anandamide and 2-arachidonoylglycerol include the heat shock proteins (Hsp70s) and fatty acid binding proteins (FABPs). [31] [32]
Anandamide shows a preference for binding to cholesterol and ceramide over other membrane lipids. Cholesterol acts as a binding partner for anandamide. Initially, a hydrogen bond facilitates their interaction. Following this, anandamide is drawn towards the membrane interior, where it forms a molecular complex with cholesterol. This process involves a conformational adaptation of anandamide to the apolar membrane environment. Subsequently, the anandamide-cholesterol complex is directed to the cannabinoid receptor (CB1) and then exits. [33]
Cannabinoids are several structural classes of compounds found in the cannabis plant primarily and most animal organisms or as synthetic compounds. The most notable cannabinoid is the phytocannabinoid tetrahydrocannabinol (THC) (delta-9-THC), the primary psychoactive compound in cannabis. Cannabidiol (CBD) is also a major constituent of temperate cannabis plants and a minor constituent in tropical varieties. At least 100 distinct phytocannabinoids have been isolated from cannabis, although only four have been demonstrated to have a biogenetic origin. It was reported in 2020 that phytocannabinoids can be found in other plants such as rhododendron, licorice and liverwort, and earlier in Echinacea.
Cannabinoid receptors, located throughout the body, are part of the endocannabinoid system of vertebrates– a class of cell membrane receptors in the G protein-coupled receptor superfamily. As is typical of G protein-coupled receptors, the cannabinoid receptors contain seven transmembrane spanning domains. Cannabinoid receptors are activated by three major groups of ligands:
Tetrahydrocannabivarin is a homologue of tetrahydrocannabinol (THC) having a propyl (3-carbon) side chain instead of pentyl (5-carbon), making it non-psychoactive in lower doses. It has been shown to exhibit neuroprotective activity, appetite suppression, glycemic control and reduced side effects compared to THC, making it a potential treatment for management of obesity and diabetes. THCV was studied by Roger Adams as early as 1942.
EX-597 is a fatty acid amide hydrolase inhibitor which is under development for the treatment of social anxiety disorder and post-traumatic stress disorder (PTSD).
The endocannabinoid system (ECS) is a biological system composed of endocannabinoids, which are neurotransmitters that bind to cannabinoid receptors, and cannabinoid receptor proteins that are expressed throughout the central nervous system and peripheral nervous system. The endocannabinoid system is still not fully understood, but may be involved in regulating physiological and cognitive processes, including fertility, pregnancy, pre- and postnatal development, various activity of immune system, appetite, pain-sensation, mood, and memory, and in mediating the pharmacological effects of cannabis. The ECS plays an important role in multiple aspects of neural functions, including the control of movement and motor coordination, learning and memory, emotion and motivation, addictive-like behavior and pain modulation, among others.
Fatty-acid amide hydrolase 1 (FAAH) is a member of the serine hydrolase family of enzymes. It was first shown to break down anandamide (AEA), an N-acylethanolamine (NAE) in 1993. In humans, it is encoded by the gene FAAH.
2-Arachidonoylglycerol (2-AG) is an endocannabinoid, an endogenous agonist of the CB1 receptor and the primary endogenous ligand for the CB2 receptor. It is an ester formed from the omega-6 fatty acid arachidonic acid and glycerol. It is present at relatively high levels in the central nervous system, with cannabinoid neuromodulatory effects. It has been found in maternal bovine and human milk. The chemical was first described in 1994–1995, although it had been discovered some time before that. The activities of phospholipase C (PLC) and diacylglycerol lipase (DAGL) mediate its formation. 2-AG is synthesized from arachidonic acid-containing diacylglycerol (DAG).
AM404, also known as N-arachidonoylphenolamine, is an active metabolite of paracetamol (acetaminophen), responsible for all or part of its analgesic action and anticonvulsant effects. Chemically, it is the amide formed from 4-aminophenol and arachidonic acid. AM404 is one of the AM cannabinoids discovered by Alexandros Makriyannis and his team.
Oleamide is an organic compound with the formula CH3(CH2)7CH=CH(CH2)7CONH2. It is the amide derived from the fatty acid oleic acid. It is a colorless waxy solid and occurs in nature. Sometimes labeled as a fatty acid primary amide (FAPA), it is biosynthesized from N-oleoylglycine.
Virodhamine (O-arachidonoyl ethanolamine; O-AEA) is an endocannabinoid and a nonclassic eicosanoid, derived from arachidonic acid. O-Arachidonoyl ethanolamine is arachidonic acid and ethanolamine joined by an ester linkage, the opposite of the amide linkage found in anandamide. Based on this opposite orientation, the molecule was named virodhamine from the Sanskrit word virodha, which means opposition. It acts as an antagonist of the CB1 receptor and agonist of the CB2 receptor. Concentrations of virodhamine in the human hippocampus are similar to those of anandamide, but they are 2- to 9-fold higher in peripheral tissues that express CB2. Virodhamine lowers body temperature in mice, demonstrating cannabinoid activity in vivo.
N-Arachidonyl glycine receptor, also known as G protein-coupled receptor 18 (GPR18), is a protein that in humans is encoded by the GPR18 gene. Along with the other previously orphan receptors GPR55 and GPR119, GPR18 has been found to be a receptor for endogenous lipid neurotransmitters, several of which also bind to cannabinoid receptors. It has been found to be involved in the regulation of intraocular pressure.
Oleoylethanolamide (OEA) is an endogenous peroxisome proliferator-activated receptor alpha (PPAR-α) agonist. It is a naturally occurring ethanolamide lipid that regulates feeding and body weight in vertebrates ranging from mice to pythons.
N-Acylphosphatidylethanolamines (NAPEs) are hormones released by the small intestine into the bloodstream when it processes fat. NAPEs travel to the hypothalamus in the brain and suppress appetite. This mechanism could be relevant for treating obesity.
N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) is an enzyme that catalyzes the release of N-acylethanolamine (NAE) from N-acyl-phosphatidylethanolamine (NAPE). This is a major part of the process that converts ordinary lipids into chemical signals like anandamide and oleoylethanolamine. In humans, the NAPE-PLD protein is encoded by the NAPEPLD gene.
An N-acylethanolamine (NAE) is a type of fatty acid amide where one of several types of acyl groups is linked to the nitrogen atom of ethanolamine, and highly metabolic formed by intake of essential fatty acids through diet by 20:4, n-6 and 22:6, n-3 fatty acids, and when the body is physically and psychologically active,. The endocannabinoid signaling system (ECS) is the major pathway by which NAEs exerts its physiological effects in animal cells with similarities in plants, and the metabolism of NAEs is an integral part of the ECS, a very ancient signaling system, being clearly present from the divergence of the protostomian/deuterostomian, and even further back in time, to the very beginning of bacteria, the oldest organisms on Earth known to express phosphatidylethanolamine, the precursor to endocannabinoids, in their cytoplasmic membranes. Fatty acid metabolites with affinity for CB receptors are produced by cyanobacteria, which diverged from eukaryotes at least 2000 Million years ago (MYA), by brown algae which diverged about 1500 MYA, by sponges, which diverged from eumetazoans about 930 MYA, and a lineages that predate the evolution of CB receptors, as CB1 – CB2 duplication event may have occurred prior to the lophotrochozoan-deuterostome divergence 590 MYA. Fatty acid amide hydrolase (FAAH) evolved relatively recently, either after the evolution of fish 400 MYA, or after the appearance of mammals 300 MYA, but after the appearance of vertebrates. Linking FAAH, vanilloid receptors (VR1) and anandamide implies a coupling among the remaining ‘‘older’’ parts of the endocannabinoid system, monoglyceride lipase (MGL), CB receptors, that evolved prior to the metazoan–bilaterian divergence, but were secondarily lost in the Ecdysozoa, and 2-Arachidonoylglycerol (2-AG).
Palmitoylethanolamide (PEA) is an endogenous fatty acid amide, and lipid modulator.
The endocannabinoid transporters (eCBTs) are transport proteins for the endocannabinoids. Most neurotransmitters are water-soluble and require transmembrane proteins to transport them across the cell membrane. The endocannabinoids on the other hand, are non-charged lipids that readily cross lipid membranes. However, since the endocannabinoids are water immiscible, protein transporters have been described that act as carriers to solubilize and transport the endocannabinoids through the aqueous cytoplasm. These include the heat shock proteins (Hsp70s) and fatty acid-binding proteins for anandamide (FABPs). FABPs such as FABP1, FABP3, FABP5, and FABP7 have been shown to bind endocannabinoids. FABP inhibitors attenuate the breakdown of anandamide by the enzyme fatty acid amide hydrolase (FAAH) in cell culture. One of these inhibitors (SB-FI-26), isolated from a virtual library of a million compounds, belongs to a class of compounds that act as an anti-nociceptive agent with mild anti-inflammatory activity in mice. These truxillic acids and their derivatives have been known to have anti-inflammatory and anti-nociceptive effects in mice and are active components of a Chinese herbal medicine used to treat rheumatism and pain in human. The blockade of anandamide transport may, at least in part, be the mechanism through which these compounds exert their anti-nociceptive effects.
N-acyl amides are a general class of endogenous fatty acid compounds characterized by a fatty acyl group linked to a primary amine metabolite by an amide bond. Broadly speaking, N-acyl amides fall into several categories: amino acid conjugates, neurotransmitter conjugates, ethanolamine conjugates, and taurine conjugates. N-acyl amides have pleiotropic signaling functions in physiology, including in cardiovascular function, metabolic homeostasis, memory, cognition, pain, motor control and others. Initial attention focused on N-acyl amides present in mammalian organisms, however recently lipid signaling systems consisting of N-acyl amides have also been found to be present in invertebrates, such as Drosophila melanogaster. N-acyl amides play important roles in many biochemical pathways involved in a variety of physiological and pathological processes, as well as the metabolic enzymes, transporters, and receptors that regulate their signaling.
An endocannabinoid enhancer (eCBE) is a type of cannabinoidergic drug that enhances the activity of the endocannabinoid system by increasing extracellular concentrations of endocannabinoids. Examples of different types of eCBEs include fatty acid amide hydrolase (FAAH) inhibitors, monoacylglycerol lipase (MAGL) inhibitors, and endocannabinoid transporter (eCBT) inhibitors. An example of an actual eCBE is AM404, the active metabolite of the analgesic paracetamol and a dual FAAH inhibitor and eCBRI.
Jo Cameron, also known as Patient PFS, is a Scottish woman who feels no pain and experiences little to no anxiety or other aspects of negative affect.