Ligand efficacy

Fig. 3. Ligand efficacy. The effect of different classes of drugs on a GPCR that has some detectable basal activity.

Griffin G, Wray EJ, Rorrer WK, Crocker PJ, Ryan WJ, Saha B, Razdan RK, Martin BR, Abood ME (1999) An investigation into the structural determinants of cannabinoid receptor ligand efficacy. Br J Pharmacol 126 1575-1584... 

After the formation of an RL eomplex, a functional response to receptor activation can be related to the concentration of the ligand present (Fig. 10.1a). Occupancy theory, developed by Clark in 1926 (22), is based on a dose/ concentration-response relationship. This theory has undergone eontinuous refinement based on experimental data to aid in further delineating the increasingly complex coneept of ligand efficacy (23) and to accommodate allosteric site modulation of receptor function (21,24,25), ternary complex models, (26,27) and their extension to constitutively active re-... 

In recent years, many functional assays have been developed to quantify the effect of ligands on CKR function. Concentration-response curves, in which the functional response of a ligand is plotted as a function of its concentration (Fig. 9A), provide information on ligand efficacy and... 

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