5.1 Cholinergic Flashcards
What receptor type is found only in nerves?
M1
What receptor is found in nerves, the hearts, and smooth muscle?
M2
What receptor type is found in glands, endothelium, and smooth muscle?
M3
What receptor is found only at the neuromuscular junctions?
Nm
What receptor is found in the CNS, Post-ganglionic cell body/dendrites?
Nn
How do muscarinic receptors get the signal into the cell?
G-membrane linked
How do nicotinic receptors get the signal into the cell?
Voltage-gated
In the CNS, what is the mechanism A2 receptors use for their effect?
Control Ca++ release
What catalyzes hydrolysis of ACh?
AChE
Butyryl-ChE (in plasma)
What are the cardiac effects of ACh?
Vasodilation
↓ HR (negative chronotropic effect)
↓ conduction velocity (negative dromotropic effect)
↓ force of cardiac contraction (negative inotropic effect)
What are the respiratory effects of ACh?
Regulating bronchomotor tone
Bronchoconstriction
↑ tracheobronchial secretion
What are the urinary effects of ACh?
Detrusor muscle contraction
↑ increase voiding pressure
Ureteral peristalsis
What are the GI effects of ACh?
↑ GI motility, tone
↑ amplitude of contractions
↑ secretory activity of stomach and intestine
What are the HEENT effects of ACh?
↑ lacrimation, nasopharyngeal, and sweat glands secretion
↑ salivary secretion
Contraction of pupillary sphincter muscle miosis
Contraction of ciliary muscle
What is a cholinomimetic?
Drug that mimics the actions of ACh
What is the mechanism of a direct agonist cholinomimetic?
Directly binds to ACh receptor
What is the mechanism of an indirect cholinomimetic agonist?
Affect metabolism of breakdown of ACh
= affects AChE
What type of cholinomimetic are Esters of choline and Alkaloids?
Direct cholinomimetic
What is the mechanism of Esters of choline?
Structure has charged quaternary ammonium group
Poor lipid soluble poorly absorbed poorly distributed into CNS
All hydrolyzed in GI – Less active
Differ in susceptibility to hydrolysis
What is Miochol-E used for?
Ester of choline
Cataract surgery– intraop only – induce miosis – intraoccular inj. Or topical
What is Methacholine (Provocholine) used for? Contraindications?
Mix powder w/ NS and inhale via neb
Diagnostic test – bronchial hyperresponsiveness
Asthma vs. COPD asthmatic pts produce intense bronchoconstriction
Contraindications: limited airflow; MI, stroke, uncontrolled HTN, and pregnancy
Emergency resuscitation, O2, Beta-2 agonist should be available during testing
What is Carbachol used for?
Catarac surgery – intraoccular inj or topical – induce miosis or prevent elevated IOP (intraoccular pressure)
Eye drop – no longer available in US – Open angle glaucoma
What is Bethanechol (Urecholine) used for? Contraindications?
Urinary tract – Increase detrusor muscle tone
Indications: urinary retention, inadequate emptying w/o obstruction, neurogenic bladder
Dose: 10-50mg PO TID – QID empty stomach to avoid vomiting
GI tract – stimulates peristalsis; motility; increase resting LES (lower esophageal sphincter) pressure
Indications: GERD, post-op abd distention, gastroparesis…
Caution: bradycardia, hypotension, seizure
Contraindications: Asthma, COPD, urinary or GI obstruction, CVD
Hyperthyroidism + muscarinic agonists a. Fib
