Endocannabinoid

Article By:

Piomelli, Daniele Department of Pharmacology, University of California, Irvine, California.

Last reviewed:March 2021

DOI:https://doi.org/10.1036/1097-8542.900118

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• Endocannabinoids, published June 2014:Download PDF Get Adobe Acrobat Reader

Any member of a family of endogenous lipid messengers that engage cannabinoid receptors. Endocannabinoids are endogenous cannabinoids that are related to the chemical constituents of marijuana (cannabis). They are found within the mammalian nervous system and bind to cannabinoid (CB) receptors, that is, the cell surface receptors targeted by the active principle (Δ⁹-tetrahydrocannabinol; THC) of marijuana. Endocannabinoids are produced on demand through cleavage of membrane phospholipid precursors and are utilized in the execution of a variety of short-range signaling processes. In the brain, they activate CB₁-type cannabinoid receptors on neuronal axon terminals to regulate ion channel activity and neurotransmitter release. In peripheral tissues, they activate CB₁ receptors in nerve terminals to reduce pain sensation and increase appetite. They also can engage CB₁ receptors in nonneural tissues to modulate blood pressure (in the vasculature), increase adipogenesis (the formation of fat in white adipose tissue), and stimulate fatty acid accumulation (in the liver). In addition, the endocannabinoids bind to CB₂-type receptors expressed in immune cells to influence pain and inflammatory responses. There are two established endocannabinoid transmitters: anandamide (Fig. 1) and 2-arachidonoylglycerol (2-AG). See also: Brain; Inflammation; Lipid; Marijuana; Nervous system (vertebrate); Neurobiology; Neuron; Pain; Phospholipid

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