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Title: Radioligand  
Author: World Heritage Encyclopedia
Language: English
Subject: Positron emission tomography, Autoradiograph, McN5652, MPPF, Setoperone
Publisher: World Heritage Encyclopedia


A radioligand is a radioactive biochemical substance (in particular, a ligand) that is used for diagnosis or for research-oriented study of the receptor systems of the body.

In a neuroimaging application the radioligand is injected into the pertinent tissue, or infused into the bloodstream. It binds to its receptor. When the radioactive isotope in the ligand decays it can be measured by positron emission tomography (PET) or single photon emission computed tomography (SPECT). In in vivo systems it is often used to quantify the binding of a test molecule to the binding site of radioligand. The higher the affinity of the molecule the more radioligand is displaced from the binding site and the increasing radioactive decay can be measured by scintillography. This assay is commonly used to calculate binding constant of molecules to receptors.

The transport of the radioligand is described by receptor kinetics.


  • History 1
  • Radioactive isotopes commonly used 2
  • List of radioligands 3
  • See also 4
  • References 5
    • Further reading 5.1


Radioligands are credited with making possible the study of biomolecular behaviour, a previously mysterious area of research that had evaded researchers.[1] With this capacity radioligand techniques enabled researchers to identify receptor devices within cells.

Radioactive isotopes commonly used

In PET the isotopes fluorine-18, carbon-11, and copper-64 are often used in molecular imaging.

List of radioligands

Radioligands may be constructed to bind selectively to a particular neuroreceptor or a particular neurotransmitter transporter. Examples of radioligands include:

See also


  1. ^  
  2. ^ Wong, Dean F.; Lever, John R.; Hartig, Paul R.; Dannals, Robert F.; Villemagne, Victor; Hoffman, Beth J.; Wilson, Alan A.; Ravert, Hayden T.; Links, Jonathan M. (1987). "Localization of serotonin 5-HT2 receptors in living human brain by positron emission tomography using N1-([11C]-methyl)-2-bromo-LSD".  
  3. ^ Karen H. Adams,  
  4. ^ J. C. Baron, Y. Samson, D. Comar, C. Crouzel, P. Deniker, Y. Agid (1985). "Etude in vivo des recepteurs serotoninergiques centraux chez l'homme par tomographie a positions. [In vivo study of central serotoninergic receptors in man using positron tomography]".  
  5. ^ Reimold M, Smolka MN, Zimmer A, et al. (2007). "Reduced availability of serotonin transporters in obsessive-compulsive disorder correlates with symptom severity - a [11C]DASB PET study". J Neural Transm 114 (12): 1603–9.  
  6. ^ Pertwee RG (1999). "Pharmacology of cannabinoid receptor ligands". Curr. Med. Chem. 6 (8): 635–64.  
  7. ^  
  8. ^ Seeman P, Ulpian C, Larsen RD, Anderson PS (August 1993). "Dopamine receptors labelled by PHNO". Synapse 14 (4): 254–262.  
  9. ^ Volkow ND, Wang GJ, Fowler JS, Logan J, Franceschi D, Maynard L, Ding YS, Gatley SJ, Gifford A, Zhu W, Swanson JM. (March 2002). "Relationship between blockade of dopamine transporters by oral methylphenidate and the increases in extracellular dopamine: therapeutic implications". Synapse 43 (3): 181–187.  

Further reading

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