Figure 8.

Relationship between agonist and antagonist tracer displacement (∆B _Ag and ∆B _An) and the fraction of receptors occupied by competing agonist drug or neurotransmitter. B _max is the total receptor density available at baseline, X _H is the fraction of receptors configured in the high‐affinity state, B _occ is the amount of receptors occupied as a result of the challenge. If B _occ < X _H B _max, that is, not all high‐affinity state receptors become occupied, the ratio of relative decreases of agonist and antagonist tracer binding is constant and equal to 1/X _H