Cholinergic agonist Flashcards
Exam 4
1
Q
Classifying Ach receptor agonist
A
- direct acting agonist: bind and activate ACh receptors and facilitate ACh signal transduction
- indirect acting agonist: increase synaptic concentration of ACH by inhibiting cholinesterase
2
Q
Direct acting Ach receptor agonist
A
- Bethanechol (M): GI & urinary stimulation (3 Bs - bethanechol, bowel, bladder)
- Carbachol (N &M): constricts pupil and relieves IOP in glaucoma
- Methacholine (M): challenge test for asthma (diagnoistic procedure ONLY)
- Pilocarpine (M): glaucoma, xerostomia
- Cevimeline (M): xerostomia
3
Q
ACh effect on eye
A
- contraction of iris sphincter causes miosis (constriction of pupil)
- contraction of ciliary body which controls accommodation ( decrease IOP)
- combination of those effects drains anterior chamber of eye to help glaucoma.
4
Q
Cardiovascular effect of ACh
A
- heart depends on homeostatic mechanisms and dose
- heart wants to decrease HR and cardiac output and decrease BP
- clinically don’t use drugs with these effects in heart disease
- cardiac side effects occur when muscarinic drugs are given for other reasons
5
Q
Respiratory effect of ACh
A
- BRONCHOCONSTRICTION: makes it harder to breath
- stimulates secretion of mucus in tracheobronchial tree: fills airways with mucus - makes harder to breath
- clinically: not used for the effect - avoid with asthma and obstructive lung disease
6
Q
GI effects on ACh
A
- increase secretion of GI tract: salivary glands and gastric glands
- peristalsis of intestine are increase and sphincters are released
7
Q
GU effects of ACh
A
- ACh stimulate the bladder muscle (contraction) and relaxes the sphincter
- promotes emptying of bladder
- Clinically: use if nerves to bladder are not working
- high doses of these agonist can produce urinary incontinence
8
Q
Additional effects on glands of ACh
A
-increase sweat, lacrimal, and nasopharyngeal glands secretion
9
Q
Nicotine organ effects
A
- prototype for drugs that just stimulate the nicotinic receptor
- nicotinic receptors are present in CNS, ganglion in PNS, SNS, and neuromuscular junction so a lot happens when they get activated
10
Q
CNS effects of Nicotine
A
- low does increases alertness
- higher doses cause tremor, emesis, increase respiration and coma
- addiction results from receptor stimulation in certain brain areas
11
Q
Ganglion effects of nicotine
A
- initially looks like stimulating PNS and SNS at the same time and the effect that occurs depends on which on wins out
- cardiac effects: SNS response usually wins so get increased HR and BP
- GI and GU: PNS ususally wins so get n/v/d and urination
12
Q
Skeletal neuromuscular junction effects of nicotine
A
- initally voluntary muscles contract, but the nicotine keeps stimulating the receptor so the muscle never recovers b/c constantly stimulated - paralysis
- clinically: muscle paralysis during anesthesia for surgery
13
Q
Adverse reactions of ACh receptors
A
- Muscarinic: SLUDGE M (salivation, lacrimation, urination, defecation, gastric emptying, emesis, miosis)
- Nicotinic: MTWTF (muscle cramps, tachycardia, weakness, twitching, fasciculation)
14
Q
Indirect acting ACh receptor agonist
A
- cholinesterase inhibitors
- divided into 2 groups: reversible and irreversible
15
Q
Reversible cholinesterase inhibitors
A
- quaternary compounds
- Donepezil, galantamine, rivastigmine: Alzheimer’s
- Neostigmine: myasthenia gravis, reversal of anesthetics
- Physostigmine: antidote for anticholinergic toxicity
- Pyridostigmine: myasthenia gravis, reversal of anesthetics
