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Cannabinoid receptors, located in the brain, are part of the Endocannabinoid system which is involved in a variety of physiological processes including appetite, pain-sensation, mood, and memory. Cannabinoid receptors are of a class of cell membrane receptors under 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, endocannabinoids (produced by the mammilary body), plant cannabinoids (such as Cannabidiol, produced by the cannabis plant) and synthetic cannabinoids (such as HU-210). All of the endocannabinoids and plant cannabinoids are lipophilic, such as fat soluble compounds. There are currently two known subtypes of cannabinoid receptors, termed CB1 and CB2.〔〔 The CB1 receptor is expressed mainly in the brain (central nervous system or "CNS"), but also in the lungs, liver and kidneys. The CB2 receptor is expressed mainly in the immune system and in hematopoietic cells. Mounting evidence suggests that there are novel cannabinoid receptors〔 that is, non-CB1 and non-CB2, which are expressed in endothelial cells and in the CNS. In 2007, the binding of several cannabinoids to a G protein-coupled receptor (GPCR) in the brain was described.〔 The protein sequences of CB1 and CB2 receptors are about 44% similar.〔 When only the transmembrane regions of the receptors are considered, amino acid similarity between the two receptor subtypes is approximately 68%.〔 In addition, minor variations in each receptor have been identified. Cannabinoids bind reversibly and stereo-selectively to the cannabinoid receptors. Subtype selective cannabinoids have been developed which theoretically may have advantages for treatment of certain diseases such as obesity. ==CB1== (詳細はexpressed G protein-coupled receptors in the brain. This is due to endocannabinoid-mediated depolarization-induced suppression of inhibition, a very common form of short-term plasticity in which the depolarization of a single neuron induces a reduction in GABA-mediated neurotransmission. Endocannabinoids released from the depolarized post-synaptic neuron bind to CB1 receptors in the pre-synaptic neuron and cause a reduction in GABA release. They are also found in other parts of the body. For instance, in the liver, activation of the CB1 receptor is known to increase de novo lipogenesis.〔 A 2004 study suggested that the endocannabinoids and their cannabinoid receptors play a major role during pre- and postnatal development.〔("The endocannabinoid-CB1 receptor system in pre- and postnatal life" - Ester Fride, "European Journal of Pharmacology" (Volume 500, Issues 1–3, 1 October 2004, Pages 289–297) )〕〔(The Endocannabinoid-CB Receptor System: Importance for development and in pediatric disease ) Neuroendocrinology Letters Nos.1/2, Feb-Apr Vol.25, 2004.〕 In another recent study a group of researchers combined stochastic optical reconstruction microscopy (STORM) and patch clamp in order to see CB1 distribution on a nano scale with incredible resolution.〔Cannabinoids take the brain by STORM (Summary in (SciGuru Science News ))〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cannabinoid receptor」の詳細全文を読む スポンサード リンク
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