Biogenic amine receptor

Last updated October 04, 2019

Biogenic amine receptor are a variety of neurotransmitter receptors that are sensitive to biogenic amine neurotransmitters. They mostly belong to the G protein-coupled receptor (GPCR) family of transmembrane receptors, specifically within GPCR "Family A" (Rhodopsin-like receptors).^[1] A notable exception is the serotonin 5-HT₃ receptor, which is a ligand-gated ion channel. The biogenic amine receptors include the monoamine receptors.

Neurotransmitters are endogenous chemicals that enable neurotransmission. It is a type of chemical messenger which transmits signals across a chemical synapse, such as a neuromuscular junction, from one neuron to another "target" neuron, muscle cell, or gland cell. Neurotransmitters are released from synaptic vesicles in synapses into the synaptic cleft, where they are received by neurotransmitter receptors on the target cells. Many neurotransmitters are synthesized from simple and plentiful precursors such as amino acids, which are readily available from the diet and only require a small number of biosynthetic steps for conversion. Neurotransmitters play a major role in shaping everyday life and functions. Their exact numbers are unknown, but more than 200 chemical messengers have been uniquely identified.

A biogenic amine is a biogenic substance with one or more amine groups. They are basic nitrogenous compounds formed mainly by decarboxylation of amino acids or by amination and transamination of aldehydes and ketones. Biogenic amines are organic bases with low molecular weight and are synthesized by microbial, vegetable and animal metabolisms. In food and beverages they are formed by the enzymes of raw material or are generated by microbial decarboxylation of amino acids.

G protein-coupled receptor a large protein family of receptors that detect molecules outside the cell and activate internal signal transduction pathways and cellular responses

G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein–linked receptors (GPLR), constitute a large protein family of receptors that detect molecules outside the cell and activate internal signal transduction pathways and, ultimately, cellular responses. Coupling with G proteins, they are called seven-transmembrane receptors because they pass through the cell membrane seven times.

Related Research Articles

Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group connected to an aromatic ring by a two-carbon chain (such as -CH₂-CH₂-). Examples are dopamine, serotonin and epinephrine.

A neurotransmitter receptor is a membrane receptor protein that is activated by a neurotransmitter. Chemicals on the outside of the cell, such as a neurotransmitter, can bump into the cell's membrane and along the membrane we can find receptors. If a neurotransmitter bumps into its corresponding receptor, they will bind and can trigger other events to occur inside the cell. Therefore, a membrane receptor is part of the molecular machinery that allows cells to communicate with one another. A neurotransmitter receptor is a class of receptors that specifically binds with neurotransmitters as opposed to other molecules.

An autoreceptor is a type of receptor located in the membranes of presynaptic nerve cells. It serves as part of a negative feedback loop in signal transduction. It is only sensitive to the neurotransmitters or hormones released by the neuron on which the autoreceptor sits. Similarly, a heteroreceptor is sensitive to neurotransmitters and hormones that are not released by the cell on which it sits. A given receptor can act as either an autoreceptor or a heteroreceptor, depending upon the type of transmitter released by the cell on which it is embedded.

Trace amines are an endogenous group of trace amine-associated receptor 1 (TAAR1) agonists – and hence, monoaminergic neuromodulators – that are structurally and metabolically related to classical monoamine neurotransmitters. Compared to the classical monoamines, they are present in trace concentrations. They are distributed heterogeneously throughout the mammalian brain and peripheral nervous tissues and exhibit high rates of metabolism. Although they can be synthesized within parent monoamine neurotransmitter systems, there is evidence that suggests that some of them may comprise their own independent neurotransmitter systems.

Trace amine-associated receptors (TAARs), sometimes referred to as trace amine receptors, are a class of G protein-coupled receptors that were discovered in 2001. TAAR1, the first of six functional human TAARs, has gained considerable interest in academic and proprietary pharmaceutical research due to its role as the endogenous receptor for the trace amines phenylethylamine, tyramine, and tryptamine – metabolic derivatives of the amino acids phenylalanine, tyrosine and tryptophan, respectively – ephedrine, as well as the synthetic psychostimulants, amphetamine, methamphetamine and methylenedioxymethamphetamine. In 2004, it was shown that mammalian TAAR1 is also a receptor for thyronamines, decarboxylated and deiodinated relatives of thyroid hormones. TAAR2–TAAR9 function as olfactory receptors for volatile amine odorants in vertebrates.

The G_s alpha subunit is a subunit of the heterotrimeric G protein G_s that stimulates the cAMP-dependent pathway by activating adenylyl cyclase. G_sα is a GTPase that functions as a cellular signaling protein. G_sα is the founding member of one of the four families of heterotrimeric G proteins, defined by the alpha subunits they contain: the G_αs family, G_αi/G_αo family, G_αq family, and G_α12/G_α13 family. The Gs-family has only two members: the other member is G_olf, named for its predominant expression in the olfactory system. In humans, G_sα is encoded by the GNAS complex locus, while G_olfα is encoded by the GNAL gene.

G_q protein alpha subunit is a family of heterotrimeric G protein alpha subunits. This family is also commonly called the G_q/11 (G_q/G₁₁) family or G_q/11/14/15 family to include closely related family members. G alpha subunits may be referred to as G_q alpha, G_αq, or G_qα. G_q proteins couple to G protein-coupled receptors to activate beta-type phospholipase C (PLC-β) enzymes. PLC-β in turn hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP₂) to diacyl glycerol (DAG) and inositol trisphosphate (IP₃). IP₃ acts as a second messenger to release stored calcium into the cytoplasm, while DAG acts as a second messenger that activates protein kinase C (PKC).

Trace amine associated receptor 6, also known as TAAR6, is a protein which in humans is encoded by the TAAR6 gene.

Trace amine-associated receptor 1 (TAAR1) is a trace amine-associated receptor (TAAR) protein that in humans is encoded by the TAAR1 gene. TAAR1 is an intracellular amine-activated G_s-coupled and G_q-coupled G protein-coupled receptor (GPCR) that is primarily expressed in several peripheral organs and cells, astrocytes, and in the intracellular milieu within the presynaptic plasma membrane of monoamine neurons in the central nervous system (CNS). TAAR1 was discovered in 2001 by two independent groups of investigators, Borowski et al. and Bunzow et al. TAAR1 is one of six functional human trace amine-associated receptors, which are so named for their ability to bind endogenous amines that occur in tissues at trace concentrations. TAAR1 plays a significant role in regulating neurotransmission in dopamine, norepinephrine, and serotonin neurons in the CNS; it also affects immune system and neuroimmune system function through different mechanisms.

Trace amine-associated receptor 9 is a protein that in humans is encoded by the TAAR9 gene.

Olfactory receptor 2T12 is a protein that in humans is encoded by the OR2T12 gene.

Probable G-protein coupled receptor 61 is a protein that in humans is encoded by the GPR61 gene.

3-Methoxytyramine (3-MT), also known as 3-methoxy-4-hydroxyphenethylamine, is a human trace amine that occurs as a metabolite of the neurotransmitter dopamine. It is formed by the introduction of a methyl group to dopamine by the enzyme catechol-O-methyl transferase (COMT). 3-MT can be further metabolized by the enzyme monoamine oxidase (MAO) to form homovanillic acid (HVA), which is then typically excreted in the urine.

A monoamine releasing agent (MRA), or simply monoamine releaser, is a drug that induces the release of a monoamine neurotransmitter from the presynaptic neuron into the synapse, leading to an increase in the extracellular concentrations of the neurotransmitter. Many drugs induce their effects in the body and/or brain via the release of monoamine neurotransmitters, e.g., trace amines, many substituted amphetamines, and related compounds.

Reverse transport, or transporter reversal, is a phenomenon in which the substrates of a membrane transport protein are moved in the opposite direction to that of their typical movement by the transporter. Transporter reversal typically occurs when a membrane transport protein is phosphorylated by a particular protein kinase, which is an enzyme that adds a phosphate group to proteins.

2-Methoxyamphetamine (2-MA), also known as ortho-methoxyamphetamine (OMA), is a drug of the amphetamine class. It is substantially weaker in inhibiting the reuptake of and inducing the release of the monoamine neurotransmitters compared to related agents such as amphetamine, MMA, and PMA, and may instead act as a β-adrenergic receptor agonist similarly to its N-methylated analogue methoxyphenamine.

Octopamine is an organic chemical closely related to norepinephrine, and synthesized biologically by a homologous pathway. Its name derives from the fact that it was first identified in the salivary glands of the octopus.

References

↑ Lawrence I. Gilbert (18 September 2009). Insect development: morphogenesis, molting and metamorphosis. Academic Press. pp. 644–. ISBN 978-0-12-375136-2 . Retrieved 28 November 2010.

External links

"Biogenic amines in neural signaling". Institute for Biological Information Processing. Archived from the original on 2006-07-15. Retrieved 2006-12-05.

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[Gilbert2009-1] Lawrence I. Gilbert (18 September 2009). Insect development: morphogenesis, molting and metamorphosis. Academic Press. pp. 644–. ISBN 978-0-12-375136-2 . Retrieved 28 November 2010.