Muscarinic Receptor Binding
Muscarinic Receptor Binding - Related Videos
01:25
Cholinergic Receptors: Muscarinic
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2023
The pharmacological actions of acetylcholine are elicited via its binding to two families of cholinergic receptors or cholinoceptors, namely, muscarinic and nicotinic receptors. Muscarinic receptors are G protein-coupled receptors and have five subtypes, M1–M5. All mAChR subtypes are activated by acetylcholine and blocked by the antagonist, atropine. The subtypes M1, M3, and M5 couple with the Gq subunit and activate the phospholipase C (PLC) activity, mobilizing intracellular Ca2+. Activation...
01:20
Antiasthma Drugs: Muscarinic Receptor Antagonists
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2024
Muscarinic receptor antagonists, also known as antimuscarinic agents, are a class of bronchodilators used to treat asthma, although they are more commonly used to treat COPD. They work by inhibiting the action of acetylcholine (ACh), a neurotransmitter, on muscarinic receptors found in the airways. Antimuscarinic agents compete with ACh for the same binding site on the muscarinic receptors. By binding to these receptors, they inhibit the downstream effects of ACh and block the parasympathetic...
07:09
Subcutaneous Administration of Muscarinic Antagonists and Triple-Immunostaining of the Levator Auris Longus Muscle in Mice
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Cited by 7 •
2011
We describe procedures for repeated administration of inhibitors of muscarinic signaling to the levator auris longus (LAL) muscle of young adult mice and for subsequent immunostaining of its neuromuscular junctions (NMJs) in wholemounts. The LAL muscle has unique advantages for revealing in vivo pharmacological effects on NMJs.
06:27
Competitive Binding Assay to Identify Compounds Disrupting Receptor-Ligand Interactions
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2025
In this video, we describe a flow cytometry-based competitive binding assay to detect the interactions between the CXC Chemokine Receptor 4 (CXCR4) and its fluorescently-labeled natural ligand CXC Chemokine Ligand 12 (CXCL12), in the presence of a CXCR4-targeting small molecule. Incubating CXCR4-expressing cells with lower small molecule concentrations allows CXCR4-CXCL12 binding to some extent, which progressively declines upon a gradual increase in small molecule concentrations.
10:13
Measuring G-protein-coupled Receptor Signaling via Radio-labeled GTP Binding
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Cited by 11 •
2017
Guanosine triphosphate (GTP) binding is one of the earliest events in G-Protein-Coupled Receptor (GPCR) activation. This protocol describes how to pharmacologically characterize specific GPCR-ligand interactions by monitoring the binding of the radio-labeled GTP analog, [35S]guanosine-5'-O-(3-thio)triphosphate ([35S]GTPγS), in response to a ligand of interest.
FAQs
The receptor subtype determines which intracellular signaling pathway is favored. M1, M3, and M5 receptors primarily couple to Gq and stimulate phospholipase C, whereas M2 and M4 receptors couple to Gi and inhibit adenylyl cyclase. This distinction helps explain why ligands acting at different muscarinic subtypes can produce different effects on parasympathetic functions.
Subtype selectivity links a ligand’s binding profile to its likely pharmacological effects. A compound that preferentially interacts with one receptor subtype may influence a particular signaling pathway more strongly than others, while broader binding may affect several responses. Comparing subtype interactions therefore helps distinguish potentially targeted actions from less selective muscarinic effects.
Affinity indicates how strongly a ligand interacts with muscarinic receptors, while receptor density reflects how many receptors are present in the tested system. Competitive inhibition assesses whether another compound can interfere with ligand binding. Together, these measurements distinguish the strength of an interaction from receptor abundance and reveal how competing ligands influence binding.
A ligand-binding assay evaluates interactions between muscarinic receptors and acetylcholine or a drug. Pharmacologists use the resulting binding data to determine affinity, selectivity, receptor density, and competitive inhibition. These measurements provide a quantitative basis for comparing ligands and for relating receptor interactions to the pharmacological properties of candidate compounds.
Researchers use these studies to evaluate compounds intended to activate or block muscarinic receptors. Binding results can show whether a candidate has the desired receptor interaction and whether it favors particular subtypes. This information supports development and assessment of muscarinic agonists and antimuscarinic drugs for neurological, cardiovascular, respiratory, and gastrointestinal conditions.
Binding data connect molecular drug interactions with receptor systems involved in heart rate, smooth-muscle activity, and glandular secretion. Because muscarinic signaling contributes to several parasympathetic functions, affinity and selectivity measurements help researchers compare drug actions across neurological, cardiovascular, respiratory, and gastrointestinal contexts. The findings guide interpretation of intended effects and possible differences among compounds.