Muscarinic acetylcholine receptor M5
protein-coding gene in the species Homo sapiens
The human muscarinic acetylcholine receptor M5, encoded by the CHRM5 gene, is a member of the G protein-coupled receptor superfamily of integral membrane proteins. It is coupled to Gq protein. Binding of the endogenous ligand acetylcholine to the M5 receptor triggers a number of cellular responses such as adenylate cyclase inhibition, phosphoinositide degradation, and potassium channel modulation. Muscarinic receptors mediate many of the effects of acetylcholine in the central and peripheral nervous system. The clinical implications of this receptor have not been fully explored; however, stimulation of this receptor is known to effectively decrease cyclic AMP levels and downregulate the activity of protein kinase A (PKA).
Ligands
No highly selective agonists or antagonists for the M5 receptor have been discovered as of 2018, but several non-selective muscarinic agonists and antagonists have significant affinity for M5.
The lack of selective M5 receptor ligands is one of the main reasons that the medical community has such a limited understanding of the M5 receptors effects as the possibility that any and/or all effects of non-selective ligands may be due to interactions with other receptors can not be ruled out. Some data may be obtained by observing which effects are common among semi-selective ligands (ex. a ligand of M1 and M5, a ligand of M2 and M5, and a ligand of M3 and M5), but until both a selective agonist and a selective antagonist of the M5 receptor are developed this data must be considered merely theoretical.
Agonists
Acetylcholine
Bethanechol
Methacholine
Milameline ((E)-1,2,5,6-Tetrahydro-1-methyl-3-pyridinecarboxaldehyde-O-methyloxime, CAS# 139886-32-1)
Pilocarpine
Positive allosteric modulators
ML-380
ML-326
VU-0238429: EC50 = 1.16 μM; >30-fold selectivity versus M1 and M3, inactive at M2 and M4.
This brief starts where responsible research should: with the source description of “Muscarinic acetylcholine receptor M5” as protein-coding gene in the species Homo sapiens. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the science & nature register because the source frames it as protein-coding gene in the species Homo sapiens. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Oct 20, 2025. The linked authority identifier is Q15333405. None of the 0 selected statements returned an explicit reference. The first chronological checks are 2018.
Scientific names, classifications and consensus can change while older terminology persists in catalogues and historical literature. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Check terminology, classification and the date of the cited evidence. Scientific names and technical consensus can change while older records retain historical value.
- Current terminology
- Classification context
- Finding cited technical literature
Primary datasets, specimen catalogues, standards bodies and the most recent peer-reviewed literature.
Three-step research path
- Establish the record: confirm the title “Muscarinic acetylcholine receptor M5”, its source revision and the description used here.
- Expand the search: follow Muscarinic acetylcholine receptor M5 primary sources, Muscarinic acetylcholine receptor M5 archive and Muscarinic research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Muscarinic acetylcholine receptor M5”?
- Is the terminology current, historical or disputed?
- Which observation, specimen, dataset or publication supports the account?
Search terms from this dossier
This entry incorporates text from “Muscarinic acetylcholine receptor M5” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.