Autonomic Cholinergic Pharmacology Flashcards
Where does acetylcholine act?
autonomic ganglia, parasympathetic neuroeffector junctions, somatic neuromuscular junctions, adrenal medulla, and central nervous system
What are cholinergic or cholinomimetic drugs?
drugs that produce ACh-like effects
What are direct-acting cholinergic or choliinomimetic drugs?
agonists at the muscarinic ACh receptors
What are cholinesterase inhibitors?
blockers of the acetylcholinesterases that degrade endogenous ACh
What are parasympatholytic drugs?
drugs that block or inhibit ACh-like effects at parasympathetic neuroeffector nunctions (mAChR antagonists)
Generally, how do cholinergic receptor agonists act on the heart?
they are inhibitory - decrease SA rate, decrease contractile strength of the atria, decrease conduction velocity of the AV node
How do cholinergic receptor agonists act on the lungs?
contraction of the bronchial muscle and stimulation of the bronchial glands
How do cholinergic receptor agonists work on the gastrointestinal tract?
increased motility
How do cholinergic receptor agonists act on the bladder?
detrussor contraction and trigone/spinchter relaxation (peeing)
How do cholinergic receptor agonists act on the glands?
secretion
What muscarinic receptors primarily mediate the gastrointestinal tract?
M1 receptors
What muscarinic receptors primarily mediate the cardiovascular system?
M2 receptors
What muscarinic receptors primarily mediate everything else (urinary bladder, the eye)?
M3 receptors
What are cholinomimetic alkaloids?
naturally occurring alkaloids that act like acetylcholine
What are the cholinomimetic alkaloids that we discussed in class?
pilocarpine, arecoline, muscarine
What choline esters were discussed in class?
acetylcholine, methacholine, carbachol, and bethanechol
What is bethanecol used for?
stimulating GI motility in horses with ileus and stimulating the urinary bladder
What is pilocarpine used to treat?
glaucoma and KCS
How does pilocarpine treat glaucoma?
Direct stimulation of the muscarinic receptors on the pupil to constrict it, change the geometry of the eye, and promote aqueous humor flow
How does polocarpine treat KCS (dry eye)?
it stimulates the muscarinic receptors on the lacrimal gland which will thus stimulate tear production
What are the adverse effects of parasympathomimetics?
Slowing of heart rate and AV block, increased airway resistance (dyspnea), hypotension, and SLUD syndrome
What does ‘SLUD’ stand for?
salivation, lacrimation, urination, and defecation
What happens with using higher concentrations of carbachol or other muscarinic targeted drugs?
There are nicotinic effects - stimulation of sympathetic ganglia, catecholamine release from the adrenal gland, skeletal muscle fasiculations
What does acetylcholinesterase do?
terminates the action of endogenous ACh at just about every site where ACh is released
What reversible cholinesterase inhibitors did we discuss in class?
physostigmine, neostigmine, edrophonium, pyridostigmine
What is edrophonium used for?
the diagnosis of myasthenia gravis
What is pyridostigmine used for?
for treatment of myasthenia gravis
What are the irreversible cholinesterase inhibitors that we discussed in class?
Organophosphates - malathion, parathion, dichlorvos, sarin, tabun, and soman (nerve gas)
What does mild exposure to organophosphate toxicity cause?
pupillary constriction, tightness in the chest, watery discharge from the nose, wheezing
What does severe exposure to organophosphate toxicity cause?
DUMBLES - diarrhea, urination, miosis, bronchoconstriction, excitation of skeletal muscle, lacrimation, and salivation and sweating
What type of drugs are atropine and glycopyrrolate?
They are muscarinic receptor antagonists
What are the physiological effects of atropine?
tachycardia, relaxes the gastrointestinal system and decreases secretion, bronchodilation and decreased secretion, and dry oral mucosa
