SEARCH RESULTS FOR: Acetylcholinesterase-inhibitors

Acetylcholinesterase inhibitors

Authors: Trevor Low Sunny Fong Reviewers: Billy Sun* Melinda Davis* * MD at time of publication Overstimulation of nicotinic acetylcholine receptors Overstimulation of muscarinic acetylcholine receptors Involuntary muscle twitches ↑Activity of respiratory smooth muscle & glands Acetylcholinesterase inhibitors: Mechanism of action and side effects Administration of acetylcholinesterase inhibitor (e.g., neostigmine or pyridostigmine) Reversible inhibition of acetylcholinesterase activity Cholinergic effects ↓ Breakdown of acetylcholine in the synaptic cleft Acetylcholine accumulates in the synaptic cleft Excessive accumulation of acetylcholine in synapses Acetylcholine competitively displaces non-depolarizing neuromuscular blockers** from nicotinic receptors in the neuromuscular junction ↑ Acetylcholine binding to pre-synaptic nicotinic receptors on neurons ↑ acetylcholine binding to post-synaptic nicotinic receptors on muscles Pre-synaptic nicotinic receptor depolarizes terminal membrane Post-synaptic nicotinic receptor activation results in action potential in muscle ↑ Vesicular release of acetylcholine by voltage- gated calcium signaling Muscle contraction occurs via excitation- contraction coupling Legend: Neurotransmission is sustained during Reversal of neuromuscular block repeated stimulation **See corresponding Calgary Guide slide Mechanism ↑ Activation of muscarinic receptors in myocardium ↑ Activation of muscarinic receptors in endothelial tissue Endothelial cells release nitric oxide Acetylcholine- activated potassium channels open Nitrous oxide causes vascular smooth muscle relaxation Sinoatrial node of the heart becomes hyperpolarized Vasodilation ↓ Vascular resistance Bradycardia Hypotension Depolarization block of nicotinic receptors in muscles Flaccid skeletal muscle paralysis Respiratory muscle paralysis & failure Bronchospasm & excess secretions Prolonged period of inadequate respiration ↓ Oxygen saturation ↑ Carbon dioxide ↑ Activation of gastrointestinal muscarinic receptors Stimulation of gastrointestinal muscles Activation of salivary muscarinic receptors ↑ Amplitude & duration of gut peristalsis ↑ Activity of salivary glands Overstimulation of the enteric nervous system Nausea ± vomiting ↑ Salivation Pathophysiology Sign/Symptom/Lab Finding Complications Published May 31, 2025 on www.thecalgaryguide.com