cholinoceptor-activating and cholinesterase inhibiting drugs Flashcards
acetylcholine
rapidly hydrolyzed by cholinesterase (ChE)
duration 5-30 sec
poor lipid solubility
bethanechol (and carbachol)
M receptors: increases DAG, IP3 -bladder and bowel atony resistant to ChE orally active poor lipid solubility duration 30 mins-2 hours
pilocarpine
M receptors: increases DAG, IP3
-Sjogrens syndrome (increases salivation), glaucoma (causes myosis, cyclospasm)
good lipid solubility
-30-2 hours
nicotine
N receptors: opens Na-K ion channels in ganglia and skeletal NME plates
like pilocarpine
-duration of 1-6 hours
high lipid solubility
varenicline
N receptors partial agonist at N receptors -smoking cessation high lipid solubility duration 12-24 hours
indirect acting drugs
edrophonium neostigmine physostigmine pyridostigmine echothiophate parathion
edrophonium
inhibitor of cholinesterase, amplifier of acetylcholine
-reversal of Nm blocker, diagnosis of MA gravis
alcohol
quaternary amine
poor lipid solubility, used IV
NOT ORALLY ACTIVE
dur. 5-15 mins
neostigmine
like edrophonium, reversal of Nm blocker, carbamate quaternary amine poor lipid solubility (LS) ORALLY ACTIVE dur. 30mins-2 hours
physostigmine
like edrophonium -reversal of severe atropine poisoning carbamate tertiary amine good LS orally active dur. 30min-2 hours
pyridostigmine
like edrophonium carbamate -treat MA gravis like neo dur 4-8 hours
echothiophate
organophosphate
moderate LS
2-7 days
parathion
organophosphate
high LS
7-30 days
muscarinic MOA: M1 and M3
Gq coupled receptors to phospholipase C-> second messangers DAG and IP3
DAG-> protein kinase C
IP3-> release of Ca
muscarinic MOA: M2
coupled to adenylyl cyclase through Gi
carbamates and organophosphates inhibitors
bind to cholinesterase and undergo prompt hydrolysis
-prevents binding and hydrolysis of acetylcholine
AMPLIFY ACETYLHCHOLINE EFFECTS
