Cholinergic Receptors and Agents Acting at the NMJ Flashcards
Two types of nicotinic cholinergic receptors
Muscle type (neuromuscular) and neuronal (ganglional)
Acetylcholine synthesis: rate-limiting step
Choline enters a neuron via carrier-mediated transport
Tubocurarine: site of drug action
Nicotinic receptor antagonist
Alpha-bungarotoxin: site of action
blocks postsynaptic nicotinic receptor
Beta-bungarotoxin: site of action
blocks presynaptic RELEASE of neurotransmitters
RECALL CHOLINOMIMETIC DRUGS DIAGRAM
RECALL!!!!!!!
Direct-acting cholinoceptor agents [2]
Choline esters
Alkaloids
Bethanechol, Carbachol: PK features
promotes micturition, B-methyl group present
Bethanechol is muscarinic, carbachol is muscarinic and nicotinic
Pilocarpine: PK features
good lipid solubility, for glaucoma
acts on muscarinic receptor
Nicotine: PK features
acts on nicotinic, similar to pilocarpine
Varenicline: PK features
partial agonist at nicotinic receptors, high lipid solubility, used in nicotine patches
[T/F] Site of drug action of peripherally-acting cholinesterases inhibitors is via degradation.
T.
They inhibit Achesterase and buterylcholinesterase to cause increase in concentration of Ach, which enhances cholinergic transmission
Anticholinesterase: Edrophonium
short-acting, binds reversibly to anionic site of enzyme, mainly for diagnostic purposes
Anticholinesterase: Neostigmine, Pyridostigmine, Physostigmine
medium-duration, maintenance drug for myasthenia gravis
Anticholinesterase: Organophosphates
irreversible, permanently binds to and deactivates Achesterase
Pralidoxime
a cholinesterase regenerator, antidote to organophosphate toxicity
Toxicity of indirect-acting agents: Signs and symptoms
DUMBELS: Diarrhea Urination Myosis Bronchocostriction Excitation Lacrimation Salivation
[T/F] Centrally-acting cholinesterase inhibitors are used in the symptomatic treatment of Alzheimer’s disease and dementia.
T
RECALL CHOLINOCEPTOR BLOCKERS AND CHOLINESTERASE REGENERATORS DIAGRAM
RECALL!!!!!!!!
Cholinoceptor blockers: MOA
Inhibition of choline uptake
Inhibition of Ach release
Blocking of postsynaptic receptors or ion channels
Persistent postsynaptic depolarization
Muscarinic antagonists examples
Atropine, Scopolamine
Hemocholinium: site of action
Reuptake, blocks transport of choline
Triethylcholine: site of action
Synthesis of NT, block transport of choline forms false NT
Aminoglycoside antibiotics: site of action
blocks RELEASE of Ach
