Editing Neurotransmitter receptor (section)

==Ionotropic receptors: neurotransmitter-gated ion channels==

[[Image:LGIC.png|thumb|Ligand-gated ion channel]]

'''[[Ligand-gated ion channels]]''' ('''LGICs''') are one type of ionotropic receptor or [[Ion channel linked receptors|channel-linked receptor]].  They are a group of [[transmembrane]] [[ion channel]]s that are opened or closed in response to the binding of a chemical messenger (i.e., a [[ligand (biochemistry)|ligand]]),<ref>{{DorlandsDict|two/000019817|ligand-gated channel}}</ref> such as a [[neurotransmitter]].<ref name="Purves" >{{cite book | author = Purves, Dale, George J. Augustine, David Fitzpatrick, William C. Hall, Anthony-Samuel LaMantia, James O. McNamara, and Leonard E. White | title = Neuroscience. 4th ed. | publisher = Sinauer Associates | pages = 156–7 | year = 2008 | isbn = 978-0-87893-697-7}}</ref>

The binding site of [[Endogeny#Biology|endogenous]] ligands on LGICs protein complexes are normally located on a different portion of the protein (an [[allosteric regulation|allosteric]] binding site) compared to where the ion conduction pore is located. The direct link between ligand binding and opening or closing of the ion channel, which is characteristic of ligand-gated ion channels, is contrasted with the indirect function of [[metabotropic receptor]]s, which use [[Second messenger system|second messenger]]s. LGICs are also different from [[voltage-gated ion channel]]s (which open and close depending on [[membrane potential]]), and [[stretch-activated ion channel]]s (which open and close depending on mechanical deformation of the [[cell membrane]]).<ref name="Purves" /><ref name="pmid15157178">{{cite journal |vauthors=Connolly CN, Wafford KA | title = The Cys-loop superfamily of ligand-gated ion channels: the impact of receptor structure on function | journal = Biochem. Soc. Trans. | volume = 32 | issue = Pt3 | pages = 529–34 | year = 2004 | pmid = 15157178 | doi = 10.1042/BST0320529 | s2cid = 9115777 }}</ref>