Investigation of cooperativity in the binding of ligands to the D-2 dopamine receptor

Vivo, M., Lin, H. and Strange, P.G. (2005) Investigation of cooperativity in the binding of ligands to the D-2 dopamine receptor. Molecular Pharmacology, 69 (1). pp. 226-235. ISSN 0026-895X doi: 10.1124/mol.105.012443

Abstract/Summary

The D 2 dopamine receptor exists as dimers or as higher-order oligomers, as determined from data from physical experiments. In this study, we sought evidence that this oligomerization leads to cooperativity by examining the binding of three radioligands ([H-3] nemonapride, [H-3] raclopride, and [H-3] spiperone) to D 2 dopamine receptors expressed in membranes of Sf9 cells. In saturation binding experiments, the three radioligands exhibited different B-max values, and the B-max values could be altered by the addition of sodium ions to assays. Despite labeling different numbers of sites, the different ligands were able to achieve full inhibition in competition experiments. Some ligand pairs also exhibited complex inhibition curves in these experiments. In radioligand dissociation experiments, the rate of dissociation of [H-3] nemonapride or [H-3] spiperone depended on the sodium ion concentration but was independent of the competing ligand. Although some of the data in this study are consistent with the behavior of a cooperative oligomeric receptor, not all of the data are in agreement with this model. It may, therefore, be necessary to consider more complex models for the behavior of this receptor.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/13621
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > School of Pharmacy
Uncontrolled Keywords	PROTEIN-COUPLED RECEPTORS, CARDIAC MUSCARINIC RECEPTORS, NEGATIVE COOPERATIVITY, AGONIST REGULATION, H-3 RACLOPRIDE, SF9 CELLS, SITES, STATES, MODEL, RAT
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