mAChR

links: Acetylcholine Receptor reference: 9-18-2021

Muscarinic Acetylcholine Receptor (mAChR) #

• 5 Types:
  • M1 AChR (Gq excitatory) found in CNS, salivary glands, gastric glands. Mediates excitation, salivation, and sweating.
  • M2 AChR (Gi)
    • Heart: Mediates contracticle force, like parasympathetic decreases in heart rate
  • M3 AChR (Gq)
    • Exocrine glands: Lacrimation, salivation
    • This is why vaping can cause the shits for some people - it contracts the smooth muscle.
    • Lungs: bronchoconstriction
    • Eyes: miosis
    • GI tract: found in smooth muscles, it stimulates motility.
    • Blood vessels: found in endothelial cells; plays a role in nitric oxide synthesis
    • Contracts the bladder, giving the sensation of “small bladder syndrome” and increases the urge to urinate. Too little acetylcholine can lead to urine buildup and reduced the urge to urinate, which can actually contribute to bladder inflammation.
  • M4 AChR (Gi)
    • CNS
  • M5 (Gq)
    • CNS. Obscure. Unestablished function. All five mAChR genes are expressed in hippocampus R.