Cannabinoid receptor type 1 (IPR000810)

Short name: Canbinoid_rcpt_1

Overlapping homologous superfamilies


Family relationships


Cannabinoid receptors are a class of cell membrane receptors that belong to the rhodopsin-like G-protein coupled receptor (GPCR) family [PMID: 12432948, PMID: 18426493, PMID: 19273110]. Typical of G protein-coupled receptors, cannabinoid receptors contain seven transmembrane spanning domains [PMID: 19273110]. Cannabinoid receptors are activated by three major groups of ligands: endocannabinoids, such as N-arachidonoylethanolamine and 2-arachidonoyl glycerol (produced by the mammalian body), plant cannabinoids, such as tetrahydrocannabinol [PMID: 6268916, PMID: 5538858] (produced by the plant Cannabis sativa ) and synthetic cannabinoids, such as HU-210 [PMID: 7565624]. Currently, two known cannabinoid receptor subtypes have been identified, CB1 receptor and CB2 receptor [PMID: 2165569, PMID: 7689702], and are phylogenetically restricted to the chordate branch of the animal kingdom [PMID: 21079038]. The International Union of Basic and Clinical Pharmacology (IUPHAR) has identified five pharmacological targets that could be used to find new cannabinoid receptors or channels [PMID: 21079038], which has resulted in a number of cannabinoid receptors being considered. TRP vanilloid 1 (IPR024863), which is thought to function as an ionotropic cannabinoid receptor [PMID: 21079038], and some deorphanised GPCRs [PMID: 21079038]: GPR18, GPR55, GPR119. However, according to the criteria, no channel, non-CB1/CB2 established receptor or deorphanised receptor can currently be classified fully as a novel cannabinoid receptor [PMID: 21079038].

This entry represents cannabinoid receptor 1 (CB1), which is found mainly in the central nervous system and is largely responsible for mediating the effects of cannabinoid binding in the brain, with high levels occurring in the basal ganglia, hippocampus, cerebellum, cerebral cortex, with more moderate levels in the hypothalamus [PMID: 2308954, PMID: 1504787, PMID: 2165569]. The CB1 receptor is also present in some non-neuronal cells and tissues, for example leukocytes and testis [PMID: 2308954, PMID: 12037135, PMID: 9336020]. The CB1 receptor is activated by cannabinoids, generated naturally inside the body by endocannabinoids neurotransmitters, such as anandamide [PMID: 7565624, PMID: 8819477] and 2-arachidonoyl glyceride (2-AG) [PMID: 9721036]; or introduced into the body by plant cannabinoids, such as the compound tetrahydrocannabinol THC [PMID: 7565624], an active ingredient of the psychoactive drug cannabis or a related synthetic compound. The CB1 receptor has been extensively characterised for a range of biological responses [PMID: 1604713, PMID: 3520605]. Nervous system responses to THC and other cannabinoid receptor agonists include therapeutically beneficial effects of analgesia [PMID: 12182960], attenuation of the nausea and vomiting in cancer chemotherapy [PMID: 11854768], appetite stimulation in wasting syndromes [PMID: 23108552] and decreased intestinal motility [PMID: 10611417, PMID: 16911322]. Untoward side effects accompanying these therapeutic responses include alterations in cognition and memory [PMID: 19630708], dysphoria/euphoria and sedation [PMID: 12871061]. It is generally accepted that the CB1 receptor functions to mediate inhibition of on-going release of certain excitatory and inhibitory neurotransmitters [PMID: 12037135, PMID: 12052030, PMID: 16596780].

GO terms

Biological Process

GO:0007186 G protein-coupled receptor signaling pathway

Molecular Function

GO:0004949 cannabinoid receptor activity

Cellular Component

GO:0016021 integral component of membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.