Muscarinic acetylcholine receptor M3

Source: Wikipedia, the free encyclopedia.


CHRM3
Gene ontology
Molecular function
Cellular component
Biological process
Sources:Amigo / QuickGO
Ensembl
UniProt
RefSeq (mRNA)

NM_033269

RefSeq (protein)

NP_150372

Location (UCSC)Chr 1: 239.39 – 239.92 MbChr 13: 9.93 – 10.41 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

The muscarinic acetylcholine receptor, also known as cholinergic/acetylcholine receptor M3, or the muscarinic 3, is a muscarinic acetylcholine receptor encoded by the human gene CHRM3.[5]

The M3 muscarinic receptors are located at many places in the body, e.g., smooth muscles, the

emesis. Muscarinic M3 receptors are expressed in regions of the brain that regulate insulin homeostasis, such as the hypothalamus and dorsal vagal complex of the brainstem.[6] These receptors are highly expressed on pancreatic beta cells and are critical regulators of glucose homoestasis by modulating insulin secretion.[7] In general, they cause smooth muscle contraction and increased glandular secretions.[5]

They are unresponsive to PTX and CTX.

Mechanism

Like the

calcium function in vertebrates also involves activation of protein kinase C
and its effects.

Effects

Smooth muscle

Because the M3 receptor is Gq-coupled and mediates an increase in intracellular calcium, it typically causes constriction of smooth muscle, such as that observed during bronchoconstriction. However, with respect to vasculature, activation of M3 on vascular endothelial cells causes increased synthesis of nitric oxide, which diffuses to adjacent vascular smooth muscle cells and causes their relaxation and vasodilation, thereby explaining the paradoxical effect of parasympathomimetics on vascular tone and bronchiolar tone. Indeed, direct stimulation of vascular smooth muscle M3 mediates vasoconstriction in pathologies wherein the vascular endothelium is disrupted.[9]

Diabetes

The muscarinic M3 receptor regulates insulin secretion from the pancreas[7] and are an important target for understanding the mechanisms of type 2 diabetes mellitus.

Some antipsychotic drugs that are prescribed to treat schizophrenia and bipolar disorder (such as olanzapine and clozapine) have a high risk of diabetes side-effects. These drugs potently bind to and block the muscarinic M3 receptor, which causes insulin dysregulation that may precede diabetes.[6]

Other

The M3 receptors are also located in many glands, both endocrine and exocrine glands, and help to stimulate secretion in salivary glands and other glands of the body.

Other effects are:

  • increased secretions from stomach
  • eye accommodation

Agonists

No highly selective M3 agonists are yet available as of 2018, but a number of non-selective muscarinic agonists are active at M3.

Antagonists

Interactions

Muscarinic acetylcholine receptor M3 has been shown to pre-couple with Gq proteins. The polybasic c-tail of the receptor is necessary for the pre-coupling.

Arf6[13] and ARF1.[13]

See also

References

  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000133019Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000046159Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ a b "Entrez Gene: CHRM3 cholinergic receptor, muscarinic 3".
  6. ^
    S2CID 31739607
    .
  7. ^ .
  8. ^ .
  9. .
  10. ^ .
  11. .
  12. ^ Edwards Pharmaceuticals, Inc., Belcher Pharmaceuticals, Inc. (May 2010). "DailyMed". U.S. National Library of Medicine. Retrieved January 13, 2013.
  13. ^
    PMID 12799371
    .

Further reading

External links

This article incorporates text from the United States National Library of Medicine, which is in the public domain.