Neurotransmitter receptors



A neurotransmitter receptor is a membrane receptor protein. A membrane protein interacts with the lipid 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 are particularly important in neuronal and glial (involved in neuronal transmission, but not technically neurons) cells, because they allow cells to communicate with one another through chemical signals. Neurotransmitter receptors send and receive signals that trigger an electrical signal that runs along the neuron and can be passed along a neural network, by regulating the activity of ion channels A neurotransmitter receptor can be paired directly with an ion channel, but most send signals indirectly though guanyl nucleotide-binding proteins or G proteins Interactions between neurotransmitters and neurotransmitter receptors are involved in a wide range of differing reactions from the cell receiving the signal, triggering anything from activation to inhibition.

Desensitization and ligand concentration
One additional characteristic of neurotransmitter receptors is that they are subject to ligand-induced desensitization: That is, they can become unresponsive upon prolonged exposure to their neurotransmitter. Neurotransmitter receptors are present on both postsynaptic neurons and presynaptic neurons with the former being used to receive neurotransmitters and the latter for the purpose of preventing further release of a given neurotransmitter. In addition to being found in neuron cells, neurotransmitter receptors are also found in various immune and muscle tissues. Many neurotransmitter receptors are categorized as a serpentine receptor or G protein-coupled receptor because they span the cell membrane not once, but seven times. Neurotransmitter receptors are known to become unresponsive to the type of neurotransmitter they receive when exposed for extended periods of time. This phenomenon is known as ligand-induced desensitization or downregulation.

Table of neurotransmitters
 Neurotransmitters  



Known neurotransmitter receptors (table2)
α1A, α1b, α1c, α1d α2a, α2b, α2c, α2d β1, β2, β3 D1, D2, D3, D4, D5 GABAA, GABAB1a, GABAB1δ, GABAB2, GABAC NMDA, AMPA kainate, mGluR1, mGluR2, mGluR3, mGluR4, mGluR5, mGluR6, mGluR7 H1, H2, H3 Muscarinic: M1, M2, M3, M4, M5  Nicotinic: muscle, neuronal (α-bungarotoxin-insensitive), neuronal (α-bungarotoxin-sensitive) μ, δ1, δ2, κ 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1E, 5-HT1F, 5-HT2A, 5-HT2B, 5-HT2C, 5-HT3, 5-HT4, 5-HT5, 5-HT6, 5-HT7 Glycine
 * Adrenergic
 * Dopaminergic
 * GABAergic
 * Glutaminergic
 * Histaminergic
 * Cholinergic
 * Opioid
 * Serotonergic
 * Glycinergic