Synthesis of Acetylcholine

-Acetylcholine synthesis is the rate limiting step
-Choline is the rate limiting factor in the synthesis of acetylcholine
-Inactivation occurs by degradation, then reuptake

Muscarinic ACh Receptors

-Antagonists: Atropine. Symptoms: Dry as a stone, red as a beat, mad as a hatter, Constipation, tachycardia, fever, mydriasis etc.
-Trihexiphenidyl is M1 blocker used in PD for tremor
    Ipratropium is M3 blockers used in asthma/COPD
-Agonists: Bethanecol, carbachol etc. Rarely used in ileus, atonic bladder.