autonomic nervous system Flashcards
List down pharmacological actions of cholinergic drugs
heart: refactory period of av bundle and purkinji fibres reduced
force of atrial contraction is reduced bradycardia rate of impulse generation is reduced
blood vessels dilate blushing in areas of cholinergic innervation that is areas of skin and face
smooth muscles contraction increases
perilstalsis in gi tract increases
evacuation of bowel
detrusor muscle contract and the bladder is emptied
constriction of bronchial muscles
contraction of ciliary muscle reduced intraocular tension
does not penetrate the blood brain barrier but if directly injected into the brain it produces stimulation and depression
define and classify anticholinesterase
anti cholinesterase are agents that prevent the hydrolysis, produce cholinergic effects and potentiate the release of ach
reversible carbamates: physostigmine, neostigmine
irrerversible
organophosphates : dyflos, parathion , malathion
crbamates :carbaryl
pharmacological effects of pharmacokinetics of anticholinesterase
lipid soluble like organophosphates, physostigmine more muscarinic effects more effect on cns less on skeletal muscle, sympathetic ganglia is stimulated
lipid insoluble: stimulate ganglia no CNS effects stimilate ganglia direct action on muscle end plate due to action of anti ach the ach released by a single nerve dosent get destroyed, instead it rebibds to the same receptor , gets diffused to neighbouring receptors, actiavtes pre junctional fibres ,teiching and fasiculations are followed huger doses neuromuscular transmission blockade, paralysis .
uses of cholinergic, /anticholinesterase
tretament of glaucome , reduce intraocular tension pilocarpine and physostigmine are mitotics
to prevent adhesions between iris and lens
myastenia gravis
post-operatve decurarization reverse the effectsof muscle relaxants
to antagonize the currane-like action of cobra neurotoxin
alzeimers due to deficiency of ach, doenpezil, tacrine may give some symptomatic drug for symptomatic relief
for atropine posioning physostigmine is the drug of choice.
anti cholinesterase poisoning treament
termintion of further exposure to poison
maintain airway
maintain bp
atropine but it does not reverse nicotinic action ie peripheral muscular paralysis
cholieesterase reactivators
pralidoxime
