Cholinergics & Adrenergics Biology Flashcards
Muscarinic receptors bind to:
ACh, NE
Nicotinic receptors bind to
nicotine, ACh
What time of receptors are Nicotinic receptors? Muscarinic?
Na/K channels - activates and then deactivates. Muscarinic - GPCR - continual effect.
How would you treat cholinergic poisoning?
atropine (muscarinic antagonist)
How would you treat organophosphate poisoning?
pralidoxime
Why would you get paradoxical bradycardia with muscarinic receptor activation?
M receptor activation - get hypotension due to NO-mediated vasodilation, but also get paradoxical bradycardia because there are M receptors on the SA node.
What is the cholinergic syndrome?
DUMBBELSS Diarrhea Urination Miosis Bronchorrea/Bronchoconstriction Bradycardia Emesis Lacrimation Salivation Sweating
What 3 enzymes terminate ACh signaling?
True, Pseudo (blood), and RBC AChE
What are direct M. agonists?
pilocarpine (carbachol), methacoline, and bethanecol
What are indirect M agonists?
AChE inhibitors that increase ACh: Edrophoniium, Neostigmine, Pyridostigmine, Echothiophate
What happens with over-activation of N receptors? (5 things)
1) initial depolarizations, which lead to muscle fasciculations/spasms
2) prolonged occupancy of the receptor with ligand –> paradoxical flaccid paralysis
3) activation of mesolimbic reward system/dopamine secretion
4) net K efflux from muscle –> hyperkalemia + cardiac effects (arrhythmias)
What are short, intermediate, and long-acting cholinesterase inhibitors? What do they do?
potentiates ACh by preventing its degradation
short: edrophonium
Intermediate: neostigmine, physostigmine
long: echothiophate
What happens if you OD on ACh?
1) respiratory suppression due to paralysis of the diaphragm + intercostals (due to nicotinic activation)
* respiratory support is IMPT*
2) increase bronchial secretions/bronchoconstriction (due to nicotinic activation)
What are carbamates?
intermediate acting cholinesterase inhibitors (neostigmine, physostigmine)
What are organophosphates?
long acting cholinesterase inhibitors (echothiophate)