Neurotransmitter receptor

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Postsynaptic receptor
)
Figure 1. The seven transmembrane α-helix structure of a G-protein-coupled receptor.

A neurotransmitter receptor (also known as a neuroreceptor) is a membrane

communicate
with one another. A neurotransmitter receptor is a class of receptors that specifically binds with neurotransmitters as opposed to other molecules.

In

presynaptic cells, there are receptors known as autoreceptors that are specific to the neurotransmitters released by that cell, which provide feedback and mediate excessive neurotransmitter release from it.[3]

There are two major types of neurotransmitter receptors: ionotropic and metabotropic.

ligand-gated ion channels and they can be activated by neurotransmitters (ligands) like glutamate and GABA, which then allow specific ions through the membrane. Sodium ions (that are, for example, allowed passage by the glutamate receptor) excite the post-synaptic cell, while chloride ions (that are, for example, allowed passage by the GABA receptor) inhibit the post-synaptic cell. Inhibition reduces the chance that an action potential will occur, while excitation increases the chance. Conversely, G-protein-coupled receptors are neither excitatory nor inhibitory. Rather, they can have a broad number of functions such as modulating the actions of excitatory and inhibitory ion channels or triggering a signalling cascade that releases calcium from stores inside the cell.[2] Most neurotransmitters receptors are G-protein coupled.[1]

Localization

Neurotransmitter (NT) receptors are located on the surface of neuronal and glial cells. At a synapse, one neuron sends messages to the other neuron via neurotransmitters. Therefore, the postsynaptic neuron, the one receiving the message, clusters NT receptors at this specific place in its membrane. NT receptors can be inserted into any region of the neuron's membrane such as dendrites, axons, and the cell body.[5] Receptors can be located in different parts of the body to act as either an inhibitor or an excitatory receptor for a specific Neurotransmitter [6] An example of this are the receptors for the neurotransmitter Acetylcholine (ACh), one receptor is located at the neuromuscular junction in skeletal muscle to facilitate muscle contraction (excitation), while the other receptor is located in the heart to slow down heart rate (inhibitory) [6]

Ionotropic receptors: neurotransmitter-gated ion channels

Ligand-gated ion channel

transmembrane ion channels that are opened or closed in response to the binding of a chemical messenger (i.e., a ligand),[7] such as a neurotransmitter.[8]

The binding site of

stretch-activated ion channels (which open and close depending on mechanical deformation of the cell membrane).[8][9]

Metabotropic receptors: G-protein coupled receptors

A mu-opioid G-protein-coupled receptor with its agonist

transmembrane receptors that sense molecules outside the cell and activate inside signal transduction pathways and, ultimately, cellular responses. G protein-coupled receptors are found only in eukaryotes, including yeast, choanoflagellates,[10] and animals. The ligands that bind and activate these receptors include light-sensitive compounds, odors, pheromones, hormones, and neurotransmitters, and vary in size from small molecules to peptides to large proteins. G protein-coupled receptors are involved in many diseases, and are also the target of approximately 30% of all modern medicinal drugs.[11][12]

There are two principal signal transduction pathways involving the G protein-coupled receptors: the

: 1160 

Desensitization and neurotransmitter concentration

Neurotransmitter receptors are subject to ligand-induced desensitization: That is, they can become unresponsive upon prolonged exposure to their neurotransmitter. Neurotransmitter receptors are present on both

downregulation
.

Example neurotransmitter receptors

The following are some major classes of neurotransmitter receptors:[16]

See also

Notes and references

  1. ^ a b c Levitan, Irwin B.; Leonard K. Kaczmarek (2002). The Neuron (Third pg. 285 ed.). Oxford University Press.
  2. ^ a b c "Neurological Control - Neurotransmitters". Brain Explorer. 2011-12-20. Retrieved 2012-11-04.
  3. ^ "Neurotransmitter Receptors, Transporters, & Ion Channels". www.rndsystems.com.
  4. ^ "3. Neurotransmitter Postsynaptic Receptors". Web.williams.edu. Retrieved 2012-11-04.
  5. OCLC 62509134.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  6. ^ a b Goldman, B. (2010, November 17). New imaging method developed at Stanford reveals stunning details of brain connections. In Stanford medicine news center. Retrieved from https://med.stanford.edu/news/all-news/2010/11/new-imaging-method-developed-at-stanford-reveals-stunning-details-of-brain-connections.html.
  7. ^ "ligand-gated channel" at Dorland's Medical Dictionary
  8. ^
    ISBN 978-0-87893-697-7.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  9. .
  10. .
  11. ^ Filmore, David (2004). "It's a GPCR world". Modern Drug Discovery. 2004 (November): 24–28.
  12. S2CID 11979420
    .
  13. .
  14. .
  15. ^ a b "THE Medical Biochemistry Page". Web.indstate.edu. Archived from the original on 2019-01-10. Retrieved 2012-11-04.
  16. ^ ed. Kebabain, J. W. & Neumeyer, J. L. (1994). "RBI Handbook of Receptor Classification"

External links