Unit 4: Cholinergic Agonists Flashcards
2 targets of drug action for cholinergic agonists
- Postsynaptic receptor
2. Acetylcholinesterase enzyme
Acetylcholinesterase does what?
Breaks down acetylcholine
Where are nicotinic and muscarunic receptors found?
- All autonomic ganglia have nicotinic receptors
- All neuromuscular junction receptors are nicotinic
- All parasympathetic target organs have muscarunic receptors
Cholinergic agonists are divided into the following 2 groups
- Choline esters
2. Alkaloids
The alkaloids are ______ derivatives. What is important to note regarding alkaloids and cholinesterases?
Plant
Cholinesterases do not metabolize alkaloids
BETHANECHOL indication
Urinary retention
Nicotine does what to nicotinic receptors?
It is a direct agonist
Nicotine indications
Used therapeutically to help patients stop smoking
Cholinergic agonists generally have what effects?
Muscarinic
Cholinesterase inhibitors are broken into what 2 groups? How are these groups related to solubility?
Reversible (water soluble)
Irreversible (lipid soluble)
The REVERSIBLE INHIBITORS are used to treat what diseases?
- Myasthenia gravis
2. Alzheimer’s dementia
The reversible cholinesterase inhibitors tend to end with what?
- STIGMINE
- NIUM
The irreversible cholinesterase inhibitors are referred to as
Nerve gases
What effect do cholinesterase inhibitors have on acetylcholine?
They increase acetylcholine
Activation of MUSCARINIC RECEPTORS:
Effect on the EYE
Miosis (constriction of pupil)
Activation of MUSCARINIC RECEPTORS:
Effect on the CV SYSTEM
Decrease heart rate
Activation of MUSCARINIC RECEPTORS:
Effect on the RESPIRATORY SYSTEM
Bronchial constriction, increased secretions
Activation of MUSCARINIC RECEPTORS:
Effect on the GI SYSTEM
Increased motility
Sphincter relaxation
Activation of MUSCARINIC RECEPTORS:
Effect on the GU SYSTEM
Relaxation of sphincters
Bladder wall contraction
Activation of MUSCARINIC RECEPTORS:
Effect on the GLANDS
Increased secretions
Cholinergic agonists act on:
Postsynaptic receptor—some on the muscarinic one, some on the nicotinic one
Cholinesterase inhibitors act on:
Breaking down cholinesterase and therefore increasing acetylcholine
Choline esters have what in their name?
-CHOL-
What is important to note about the lipid soluble cholinesterase inhibitors?
They rapidly cross all membranes, including the blood brain barrier
