UNIT 1.33 In Vitro Muscarinic Receptor Radioligand-Binding Assays

  1. Tod Steinfeld,
  2. M. Teresa Pulido-Rios,
  3. Scott Armstrong,
  4. Sharath S. Hegde

Published Online: 1 MAR 2010

DOI: 10.1002/0471141755.ph0133s48

Current Protocols in Pharmacology

Current Protocols in Pharmacology

How to Cite

Steinfeld, T., Pulido-Rios, M. T., Armstrong, S. and Hegde, S. S. 2010. In Vitro Muscarinic Receptor Radioligand-Binding Assays. Current Protocols in Pharmacology. 48:1.33:1.33.1–1.33.18.

Author Information

  1. Theravance, South San Francisco, California

Publication History

  1. Published Online: 1 MAR 2010
  2. Published Print: MAR 2010


G-protein-coupled muscarinic receptors (mAChRs), of which there are five subtypes (M1-M5), are attractive drug targets for a number of disorders. Described in this unit are radioligand-binding assays for defining the selectivity and affinity of chemical agents at the five mAChR subtypes. Detailed methodologies and troubleshooting strategies are provided for saturation-binding studies, to estimate KD and Bmax values, and for competition-binding studies to estimate Ki values. Emphasis is placed on experimental details that are critical for executing a robust and reliable assay. Curr. Protoc. Pharmacol. 48:1.33.1-1.33.18. © 2010 by John Wiley & Sons, Inc.


  • muscarinic;
  • acetylcholine;
  • radioligand;
  • binding