[Inverse agonist: a novel discovery in receptor research]

There is a part of unligated receptors in a state of activity (R*). The active (R*) and inactive (R) receptors exist in equilibrium. Some antagonists have a higher affinity with R as compared with R*, resulting in a decrease in the proportion of R* in the equilibrium, and inducing a biological response opposite to those of agonist. These antagonists are termed inverse agonists. In some diseases caused by receptor mutation or over expression, the therapeatic benefits of inverse agonist encourage further exploration.