Pittaluga Anna
Department of Pharmacy, Pharmacology and Toxicology Section, School of Medical and Pharmaceutical Sciences, University of GenoaGenoa, Italy; Center of Excellence for Biomedical Research, University of GenoaGenoa, Italy.
Front Pharmacol. 2016 Aug 31;7:295. doi: 10.3389/fphar.2016.00295. eCollection 2016.
Group I metabotropic glutamate (mGlu) receptors consists of mGlu1 and mGlu5 receptor subtypes. These receptors are widely distributed in the central nervous system (CNS), where they preferentially mediate facilitatory signaling in neurones and glial cells, mainly by favoring phospholipase (PLC) translocation. Based on the literature so far available, group I Metabotropic glutamate receptors (mGluRs) are preferentially expressed at the postsynaptic side of chemical synapsis, where they participate in the progression of the chemical stimulus. Studies, however, have shown the presence of these receptors also at the presynaptic level, where they exert several functions, including the modulation of transmitter exocytosis. Presynaptic Group I mGluRs can be both autoreceptors regulating release of glutamate and heteroreceptors regulating the release of various transmitters, including GABA, dopamine, noradrenaline, and acetylcholine. While the existence of presynaptic release-regulating mGlu5 receptors is largely recognized, the possibility that mGlu1 receptors also are present at this level has been a matter of discussion for a long time. A large body of evidence published in the last decade, however, supports this notion. This review aims at revisiting the data from in vitro studies concerning the existence and the role of release-regulating mGlu1 receptors presynaptically located in nerve terminals isolated from selected regions of the CNS. The functional interaction linking mGlu5 and mGlu1 receptor subtypes at nerve terminals and their relative contributions as modulators of central transmission will also be discussed. We apologize in advance for omission in our coverage of the existing literature.
I 型代谢型谷氨酸（mGlu）受体由 mGlu1 和 mGlu5 受体亚型组成。这些受体广泛分布于中枢神经系统（CNS），在神经元和神经胶质细胞中，它们主要通过促进磷脂酶（PLC）易位，优先介导兴奋性信号传导。根据目前可得的文献，I 型代谢型谷氨酸受体（mGluRs）优先表达于化学突触的突触后侧，参与化学刺激的传导过程。然而，研究表明这些受体在突触前水平也有存在，在那里它们发挥多种功能，包括调节递质的胞吐作用。突触前 I 型 mGluRs 既可以是调节谷氨酸释放的自身受体，也可以是调节包括γ-氨基丁酸（GABA）、多巴胺、去甲肾上腺素和乙酰胆碱等多种递质释放的异源受体。虽然突触前释放调节性 mGlu5 受体的存在已得到广泛认可，但 mGlu1 受体在该水平是否也存在，长期以来一直是个有争议的问题。然而，过去十年发表的大量证据支持了这一观点。本综述旨在回顾来自体外研究的数据，这些数据涉及位于从中枢神经系统选定区域分离的神经末梢突触前的释放调节性 mGlu1 受体的存在及其作用。还将讨论神经末梢处 mGlu5 和 mGlu1 受体亚型之间的功能相互作用，以及它们作为中枢传递调节剂的相对贡献。对于我们在现有文献覆盖方面的遗漏，我们在此预先表示歉意。
