  A fundamental mistake in receptor theory has led to an enduring
misunderstanding of how to estimate the affinity and efficacy of an agonist.
These properties are inextricably linked and cannot be easily separated in any
case where the binding of a ligand induces a conformation change in its
receptor. Consequently, binding curves and concentration-response relationships
for receptor agonists have no straightforward interpretation. This problem, the
affinity-efficacy problem, remains overlooked and misunderstood despite it
being recognised in 1987. To avoid the further propagation of this
misunderstanding, we propose that the affinity-efficacy problem should be
included in the core curricula for pharmacology undergraduates proposed by the
British Pharmacological Society and IUPHAR.
