BIOM 3090 Lecture Notes - Lecture 14: Muscarinic Agonist, Muscarinic Acetylcholine Receptor M3, Pilocarpine
9 Jun 2018
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AChE inhibitors
- for most tissues
o SNS: increase ACh at ganglia
o PSNS: increase ACh at ganglia + increase ACh at effector cells
o Increase ACh at ganglia an tissue = PSNS DOMINANT
What response will be observed in the cardiovascular system after systemic
exposure to the following? (understand what these drugs do, what transmitters
released and what receptors are present)
- Pilocarpine:
o Activates M2 receptors in heart and decrease rate and force of
contraction
o Activates M3 and M5 receptors on endothelial cells - increase EDRF in
endothelial cells —> EDRF diffuses into smooth muscle —> dilation of
blood vessels
o muscarinic receptor agonist so binds to muscarinic in heart —>
decrease heart rate
- Nicotine
o Activates Nn at PSNS and SNS ganglia
o Blood vessels - SNS only - increase NE and epinephrine: alpha 1 →
vasoconstriction (organs and skin)+ beta2 vasodilation (skeletal
muscle)
o Increase heart rate and force of contraction
- Physostigmine
o Inhibits AChE —> increase in ACh at ganglia - activates Nn —>
stimulates SNS and PSNS
o Blood vessels - SNS only - alpha 1 —> vasoconstriction (organs and
skin) -B2 —> vasodilation (skeletal muscle)
o Heart increase SNS and PSNS input and increase ACh in heart due to
AChE inhibition and decrease rate and force of contraction
Toxicities associated with cholinomimetics
- muscarinic agonists
o Mushrooms: genus inocybe contain high levels of muscarine,
Pilocarpine overdose
- Ingestion → symptoms of muscarinic excess
o Activation of muscarinic receptors in:
▪ Tissues/organs innervated by PSNS
▪ Sweat glands + blood vessels (EDRF)
▪ CNS (excitation)
- Symptoms of muscarinic excess (DUMBBELS)
o Diarrhea
o Urination
o Miosis
o Brachycardia → slows HR
o Bronchoconstriction → bronchi constricts bronchioles b/c M3
receptors on SM
o Excitation (CNS) → M3 receptors
find more resources at oneclass.com
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Document Summary
Ache inhibitors for most tissues: sns: increase ach at ganglia, psns: increase ach at ganglia + increase ach at effector cells, increase ach at ganglia an tissue = psns dominant. What response will be observed in the cardiovascular system after systemic exposure to the following? (understand what these drugs do, what transmitters released and what receptors are present) Nicotine: activates nn at psns and sns ganglia, blood vessels - sns only - increase ne and epinephrine: alpha 1 vasoconstriction (organs and skin)+ beta2 vasodilation (skeletal muscle) Ache inhibition and decrease rate and force of contraction. Muscarinic agonists: mushrooms: genus inocybe contain high levels of muscarine, Ingestion symptoms of muscarinic excess: activation of muscarinic receptors in, tissues/organs innervated by psns, sweat glands + blood vessels (edrf, cns (excitation) Neuromuscular blockers: trimethaphan: can be used for hypersensitive crisis or dissecting aortic aneurysm rarely used clinically, only if other drugs ineffective, d-tubocurarine: used in surgical procedure to reduce skeletal muscle contraction.
