Cholinomimetics Flashcards
(24 cards)
Two natural Cholinomimetics
(1) Muscarine
(2) Pilocarpine
A sialogen that is a cholinomimetic
Pilocarpine
4 Synthetic Cholinergic Agents:
(1) Cevimeline
(2) Methacholine
(3) Bethanechol
(4) Carbachol
Cholinomimetic that’s susceptible to breakdown by esterases.
Methacholine
Cholinomimetic that has strong nicotinic receptor activity.
Carbachol
Contraindications to the use of Choline esters.
Peptic ulcers Asthma Hyperthyroid Coronary Insufficiency Organic obstruction in the bladder of the GI tract
Sarin and “Thios” are…
Irreversible acetylcholinesterase inhibitors
How do AchE’s age? And what happens when they age?
They age by losing alkyl groups.
They can no longer break down Ach once they’ve aged.
Reversible AchE Inhibitors
Edrophonium
Neostigmine
Physostigmine
IRReversible AchE Inhibitors
Sarin
Malathion
Parathion
Echothiophate
How to AchE inhibitors work chemically?
They covalently bind to the Serine-OH group at the esteratic binding site of the enzyme.
Two binding sites of AchE
1) Ionic binding site
2) Esteratic binding site
A reversible AchE Inhibitor that binds to the AchE ionic binding site, but not to the esteratic binding site.
Edrophonium
Phosphorylation of AchE enzyme causes what?
IRReversible INHIBITION
Reactivates phosphorylated AchE
Pralidoxime
BUT it only works if the enzyme hasn’t aged yet.
Carbamyl inhibitors of AchE
Stigmines:
Physostigmine
Neostigmine (N+)
Neostigmine (N+)
Doesn’t cross the blood brain barrier bc it’s charged.
Used to diagnose Myasthenia Gravis
Edrophonium
What is myasthenia gravis?
The body attacks the nicotinic receptors on muscle, causing muscle weakness.
Irreversible Organophosphate Inhibitors of AchE
All the THIOS!
Echothiophate (N+)
Sarin
Malathion
Parathion
Used to reduce intraocular pressure.
Pilocarpine
Echothiophate (N+)
Not broken down by insects
Milothion and Parathion
Used for pediculosis (lice)
Malathion
Respiratory paralysis is caused by….
Too much Ach at the Nm receptor site.
