Flashcards in Lecture 38 Deck (55)
What are the two types of cholinergic drugs?
cholinergic agonists and cholinergic antagonists
What are the two types of cholinergic agonists?
direct acting- bind to and activate
indirect acting- inhibit
What are the direct effects of ACh on the cardiovascular system?
1. vasodilation (M3)
2. decrease in cardio rate (M2)
3. decrease in the rate of conduction by SA and AV nodes (M2)
4. decrease force in contraction (M2)
How does a low dose of ACh impact the cardiovascular system?
A fall in blood pressure, but tachycardia occurs in response
How does a high does of ACh impact the cardiovascular system?
leads to a fall in blood pressure (M3) and bradycardia (M2)
How does ACh impact the vasculature?
release of NO and vasodilation
How does ACh impact the eye?
How does ACh impact the ciliary muscle?
accommodation of lens to near vision
How does ACh impact glands?
how does ACh impact the bronchi?
how does ACh impact the heart?
decreased heart rate and conduction velocity
how does ACh impact the GI?
increased peristalic activity and relaxtion of sphincters
how does ACh impact the bladder?
Contraction of detrusor muscle; relaxation of
What does atropine do?
a muscarinic antagonist
If muscarinic effects are blocked by a muscarinic antagonist such as atropine, large doses of acetylcholine produce nicotinic effects:
Vasoconstriction and increase in blood pressure
What are the two kinds of direct-acting cholinergic agonists?
1. esters of choline
What are examples of choline esters?
About choline esters?
they are quaternary ammoniums
poorly absorbed and distributed into the CNS
ACh is very rapid hydorlyzed
meth and beth are more resistant to hydrolysis
A muscarinic receptor and nicotinic agonist
used to produce an miosis effect during cataract surgery or other procedures where miosis is needed
1. postoperative urinary retention
2. atony of the bladder
Diagnosis of bronchial airway hyperreactivity in
subjects who do not have clinically apparent
What are the natural alkaloids (direct acting)?
partial muscarinic agonist
stable to hydrolysis by ACh enzyme
dry mouth due to radiotherapy
what are the adverse effects of muscarinic agonists?
4. low bp
6. abdominal pain
agonist at nicotinic receptors
Depending on the dose, nicotine depolarizes
autonomic ganglia, resulting first in stimulation
and then in paralysis.
low nicotine dose?
ganglionic stimulation by depolarization
high nicotine dose?
ganglionic and neuromuscular blockade
to stop smoking
indirect-acting cholinergic agents?
mechanism of edrophonium?
binds reversibly to the active site
of the enzyme. The inhibition is short-lived.