Related Experiment Video
Updated: Aug 17, 2026
Local Application of Drugs to Study Nicotinic Acetylcholine Receptor Function in Mouse Brain Slices
Published on: October 29, 2012
Desensitization of the nicotinic acetylcholine receptor: molecular mechanisms and effect of modulators
E L Ochoa1, A Chattopadhyay, M G McNamee
1Department of Biochemistry and Biophysics, University of California, Davis 95616.
Abstract:
1. Loss of response after prolonged or repeated application of stimulus is generally termed desensitization. A wide variety of phenomena occurring in living organisms falls under this general definition of desensitization. There are two main types of desensitization processes: specific and non-specific. 2. Desensitization of the nicotinic acetylcholine receptor is triggered by prolonged or repeated exposure to agonists and results in inactivation of its ion channel. It is a case of specific desensitization and is an intrinsic molecular property of the receptor. 3. Desensitization of the nicotinic acetylcholine receptor at the neuromuscular junction was first reported by Katz and Thesleff in 1957. Desensitization of the receptor has been demonstrated by rapid kinetic techniques and also by the characteristic "burst kinetics" obtained from single-channel recordings of receptor activity in native as well as in reconstituted membranes. In spite of a number of studies, the detailed molecular mechanism of the nicotinic acetylcholine receptor desensitization is not known with certainty. The progress of desensitization is accompanied by an increase in affinity of the receptor for its agonist. This change in affinity is attributed to a conformational change of the receptor, as detected by spectroscopic and kinetic studies. A four-state general model is consistent with the major experimental observations. 4. Desensitization of the nicotinic acetylcholine receptor can be potentially modulated by exogenous and endogenous substances and by covalent modifications of the receptor structure. Modulators include the noncompetitive blockers, calcium, the thymic hormone peptides (thymopoietin and thymopentin), substance P, the calcitonin gene-related peptide, and receptor phosphorylation. Phosphorylation is an important posttranslational covalent modification that is correlated with the regulation and desensitization of the receptor through various protein kinases. 5. Although the physiological significance of desensitization of the nicotinic receptor is not yet fully understood, desensitization of receptors probably plays a significant role in the operation of the neuronal networks associated in memory and learning processes. Desensitization of the nicotinic receptor could also possibly be related to the neuromuscular disease, myasthenia gravis.
Insights
Desensitization, a loss of response to stimuli, affects nicotinic acetylcholine receptors. This specific process, crucial for neuronal function and potentially linked to diseases like myasthenia gravis, involves receptor inactivation and affinity changes.
Area of Science:
- Neuroscience
- Molecular Biology
- Pharmacology
Background:
- Desensitization is a general biological term for loss of response to stimuli.
- Specific desensitization of nicotinic acetylcholine receptors (nAChRs) involves ion channel inactivation.
- nAChR desensitization, first described in 1957, is an intrinsic receptor property.
Purpose of the Study:
- To review the mechanisms and modulators of nicotinic acetylcholine receptor desensitization.
- To discuss the potential physiological and pathological significance of nAChR desensitization.
Main Methods:
- Analysis of rapid kinetic techniques and single-channel recordings.
- Spectroscopic and kinetic studies to detect conformational changes.
- Review of literature on nAChR desensitization modulators and mechanisms.
Main Results:
- nAChR desensitization involves increased agonist affinity and conformational changes.
- A four-state model explains key experimental observations.
- Various substances and covalent modifications, like phosphorylation, can modulate nAChR desensitization.
Conclusions:
- The precise molecular mechanism of nAChR desensitization requires further elucidation.
- nAChR desensitization may play a role in memory, learning, and neuromuscular diseases such as myasthenia gravis.
More Related Videos
09:39Drug-induced Sensitization of Adenylyl Cyclase: Assay Streamlining and Miniaturization for Small Molecule and siRNA Screening Applications
Published on: January 27, 2014
10:48Probing Nicotinic Acetylcholine Receptor Function in Mouse Brain Slices via Laser Flash Photolysis of Photoactivatable Nicotine
Published on: January 25, 2019
Related Concept Videos
01:25Cholinergic Receptors: Muscarinic
The subtypes M1, M3, and M5 couple with the Gq subunit and activate the phospholipase C (PLC) activity, mobilizing intracellular Ca2+. Activation...
01:15Cholinergic Receptors: Nicotinic
There are two types of nicotinic receptors: neuromuscular (NM/NM/N1) and neuronal (NN/NN/N2). The two families differ based on their location and selectivity to...
01:22Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
The direct-acting...
00:59Direct-Acting Cholinergic Agonists: Pharmacological Actions
01:18Indirect-Acting Cholinergic Agonists: Mechanism of Action
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...
01:23Drugs Acting on Autonomic Ganglia: Stimulants
Ganglionic stimulants activate NM nicotinic receptors in autonomic ganglia, falling into two categories: nicotine mimetics [e.g., lobeline, dimethylpiperazine, tetramethylammonium] and muscarinic receptor agonists [e.g., muscarine, methacholine]. The first category's action is rapid and blocked by nicotinic receptor antagonists, while the second category's action is delayed and blocked by atropine-like agents. Nicotine, an alkaloid, affects the heart rate by stimulating sympathetic or...