Endocannabinoid system: emerging role from neurodevelopment to neurodegeneration.
The endocannabinoid system, including endogenous ligands ('endocannabinoids' ECs), their receptors, synthesizing and degrading enzymes, as well as transporter molecules, has been detected from the earliest stages of embryonic development and throughout pre- and postnatal development. ECs are bioactive lipids, which comprise amides, esters and ethers of long chain polyunsaturated fatty acids. Anandamide (N-arachidonoylethanolamine; AEA) and 2-arachidonoylglycerol (2-AG) are the best studied ECs, and act as agonists of cannabinoid receptors. Thus, AEA and 2-AG mimic several pharmacological effects of the exogenous cannabinoid delta9-tetrahydrocannabinol (Delta(9)-THC), the psychoactive principle of cannabis sativa preparations like hashish and marijuana. Recently, however, several lines of evidence have suggested that the EC system may play an important role in early neuronal development as well as a widespread role in neurodegeneration disorders. Many of the effects of cannabinoids and ECs are mediated by two G protein-coupled receptors (GPCRs), CB1 and CB2, although additional receptors may be implicated. Both CB1 and CB2 couple primarily to inhibitory G proteins and are subject to the same pharmacological influences as other GPCRs. This new system is briefly presented in this review, in order to put in a better perspective the role of the EC pathway from neurodevelopment to neurodegenerative disorders, like Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. In addition, the potential exploitation of antagonists of CB1 receptors, or of inhibitors of EC metabolism, as next-generation therapeutics is discussed.
Basavarajappa
Balapal S
BS
Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Rd, Orangeburg, NY 10962, USA. Basavaraj@nki.rfmh.org
Nixon
Ralph A
RA
Arancio
Ottavio
O
D000818:Animals; D001921:Brain / Q000254:growth & development* / Q000503:physiopathology*; D063387:Cannabinoid Receptor Antagonists; D063385:Cannabinoid Receptor Modulators / Q000502:physiology* / Q000627:therapeutic use; D055808:Drug Discovery; D063388:Endocannabinoids; D006801:Humans; D001523:Mental Disorders / Q000188:drug therapy / Q000503:physiopathology*; D008954:Models, Biological; D009420:Nervous System / Q000254:growth & development* / Q000503:physiopathology; D019636:Neurodegenerative Diseases / Q000188:drug therapy / Q000503:physiopathology*; D043884:Receptor, Cannabinoid, CB1 / Q000502:physiology; D043882:Receptors, Cannabinoid / Q000502:physiology*; D015398:Signal Transduction
D063387:Cannabinoid Receptor Antagonists; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D043884:Receptor, Cannabinoid, CB1; D043882:Receptors, Cannabinoid