Muscarinic Agonists Flashcards
Characteristics of ACETYLCHOLINE:
muscarinic (and nicotinic), cholinergic, POSITIVE CHARGE, poor lipid solubility (does not cross BBB)
Why does acetylcholine have a short duration of action?
butyrylcholineterase (BuEt)
Is acetylcholine selective or non-selective?
is it non-selective action for M and Nn
What are the vascular effects acetylcholine has? and how does it occur?
vasoDILATOR; stimulation of M3 receptors on endothelium cells; stimulation of M3 receptors causes release of NO, which diffuses into smooth muscle causing dilation/relaxation
The negative chronotropic effects of acetylcholine are mediated by?
M2 receptors
How are negative inotropic effects produced by acetylcholine?
by decreases in intracellular Ca2+
T/F. Acetylcholine results in decreased conduction velocity of SA and AV nodes.
TRUE.
In the presence of atropine, ACh-induced stimulation of sympathetic ganglia can be observed, what does this do to blood vessels and heart rate?
vasoCONSTRICTS and increases HR.
What is the most common use of acetylcholine?
eyes (ophthalmic use); rapid and complete mitosis; stimulate muscarinic receptor in sphincter muscle
Ciliary muscle contraction by acetylcholine allows what?
opens trabecular meshwork, increasing outflow of aqueous humor, reducing intraocular pressure
What is the prototype ester?
bethanechol
What is the prototype alkaloid?
pilocarpine
Which drug is resistant to hydrolysis by cholinesterases and what does this result in?
bethanchol; and prolongs action
What effect does bethancehol have on smooth muscle?
increases smooth muscle CONTRACTION of urinary bladder and GI tract
What are the therapeutic uses of bethanechol?
postop and postpartum urinary retention, and GERD and gastric atony (increase tone of smooth muscle)
