Cholinergics Flashcards
Nicotinic receptors are located where?
Brain
Autonomic ganglia
Skeletal muscle
What receptor in the brain is associated with memory?
M1
The secondary mechanism by which M2 receptors slow heart rate is what?
M2 receptors inhibit norepinephrine release which lowers the sympathetic stimulation
Stimulation of M3 receptors in the heart can cause what effect?
Coronary vasodilation
THIS IS NOT PARASYMPATHETIC!!!! Nitric oxide is released from endothelial cells which causes local vasodilation
Pre-op, scopolamine can be used for what side effects?
dry up secretions
sedation and amnesia
anti nausea
When is Echothiophate used?
Occasionally for narrow angle glaucoma
The top 4 side effects for muscarinic agonists
Diarrhea
Abdominal cramps
Salivation
Sweating
Cardiovascular effects of cholinesterase inhibitors
Mostly like parasympathetics
Bradycardia, lower contractile force, lower CO
Decreased sympathetic stimulation from desensitized nicotinic receptors
Contraindications for muscarinic agonists.
Peptic ulcer
Bowel obstruction
Asthma
Coronary insufficiency
Do carbamates cross the BBB?
Physostigmine is tertiary and DOES
Neostigmine and pyridostigmine are quarternary and do NOT
Direct-acting cholinergic agonists bind to ____ receptors while cholinesterase inhibitors indirectly stimulate _____ receptors
Muscarinic
Muscarinic AND nicotinic
Main 2 uses for Bethanechol (urecholine)
Stimulate GI peristalsis
Encourage urinary voiding
In what 2 ways does Varenicline (Chantix) work to aid smoking cessation?
- Causes just enough dopamine release to curb the craving for nicotine
- If the person does smoke, the Chantix blocks the nicotine receptors so the smoking is less pleasurable
What is myasthenia gravis?
Muscle weakness due to antibodies attacking nicotinic receptors on the neuromuscular endplates
Does ACh cross the BBB?
Nope
It’s quartenary
Cevimeline (Evoxac) stimulates what receptors? It causes less ____ than pilocarpine
M1 and M3
Sweating
What is the only systemic use for physostigmine? How does it work to help this?
Muscarininc antagonist poisoning
It increases ACh duration to overcome the CNS effects of the antagonist
Apart from SLUDGE, what are some other signs of cholinesterase inhibitors?
Muscarinic manifestations!
Miosis, sweating, bronchoconstriction, nausea/vomiting, diarrhea
Echnothiophate forms a (reversible/irreversible) bond with AChE
Irreversible
Long-lasting effect
Peripherally, nicotine effects may be similar to what?
BOTH parasympathetic and sympathetic neuron discharge
Muscarinic antagonist poisoning: what kind of toxicity and what can be used to help treat it?
CNS toxicity
Physostigmine (bc no good muscarinic agonists enter CNS)
What are the 2 nerve agents we learned?
Sarin
Soman
Would you want to use carbamates orally?
Only physostigmine
After ACh is released and it diffuses to the skeletal muscle, what happens?
Nicotinic receptors are stimulated