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A neurotransmitter receptor (also known as a neuroreceptor) is a membrane receptor protein that is activated by a neurotransmitter. A membrane protein interacts with the phospholipid bilayer that encloses the cell and a membrane receptor protein interacts with a chemical in the cells external environment, which binds to the cell.〔 Membrane receptor proteins, in neuronal and glial cells, allow cells to communicate with one another through chemical signals. In postsynaptic cells, neurotransmitter receptors receive signals that trigger an electrical signal, by regulating the activity of ion channels. The binding of neurotransmitters to specific receptors can change the membrane potential of a neuron. This can result in a signal that runs along the axon and can be passed along a neural network〔 (see action potential). On presynaptic cells the binding of a neurotransmitter to a specific receptor provides feedback and mediates excessive neurotransmitter release.〔(【引用サイトリンク】title= Neurotransmitter Receptors, Transporters, & Ion Channels )〕 There are two types of neurotransmitter receptors: ligand-gated receptors or ''ionotropic'' receptors and G protein-coupled receptors or ''metabotropic'' receptors.〔〔(【引用サイトリンク】title=3. Neurotransmitter Postsynaptic Receptors )〕 Ligand-gated receptors can be excited by neurotransmitters (ligands) like glutamate and aspartate. These receptors can also be inhibited by neurotransmitters like GABA and glycine. Conversely, G protein-coupled receptors are neither excitatory nor inhibitory. Rather, they modulate the actions of excitatory and inhibitory neurotransmitters.〔 Most neurotransmitters receptors are G-protein coupled.〔 ==Ionotropic receptors: neurotransmitter-gated ion channels== Ligand-gated ion channels (LGICs) are one type of ionotropic receptor or channel-linked receptor. They are a group of transmembrane ion channels that are opened or closed in response to the binding of a chemical messenger (i.e., a ligand), such as a neurotransmitter. The binding site of endogenous ligands on LGICs protein complexes are normally located on a different portion of the protein (an 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 receptors, which use second messengers. LGICs are also different from voltage-gated ion channels (which open and close depending on membrane potential), and stretch-activated ion channels (which open and close depending on mechanical deformation of the cell membrane).〔 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「neurotransmitter receptor」の詳細全文を読む スポンサード リンク
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