Fig. (1).

A sampling of the many possible effects allosteric modulators may have on the concentration-response curve to an agonist. Independent increases or decreases in the location parameter and maximal abscissae of these curves as well as incomplete saturable effects (limited shifts of the curve or changes in maxima) are possible. In effect, the allosteric modulator theoretically can create a completely new receptor with unique responsiveness to various probes such as agonists and/or radioligands.