color pdf

BIMM118
Cholinergic System - Antagonists
Nicotinic Parasympatholytics
Two classes (both act as neuromuscular blockers => muscle relaxants):
• Competitive antagonists = Nondepolarizing blockers
– Act by competing with AcCh for binding to the N receptors
– Prevent depolarization of the endplate
– Action can be reversed by increasing AcCh concentrations (e.g. via AcCh-esterase inhibitors)
• Agonists = Depolarizing blockers
– AcCh mimetics that are not hydrolyzed by AcCh-esterase (but hydrolyzed by plasma esterases)
– Act by triggering a sustained depolarization of the neuromuscular endplate
– No new action potential can be generated
– Can NOT be reversed increasing AcCh concentrations (would cause further depolarization)