Estimation of antagonist Kb from inhibition curves in functional experiments: alternatives to the Cheng-Prusoff equation

Trends Pharmacol Sci. 1993 Jun;14(6):237-9. doi: 10.1016/0165-6147(93)90018-f.


Recent Principles articles have considered procedures for the functional estimation of an antagonist's dissociation constant from the results of an antagonist inhibition curve in the presence of a fixed concentration of agonist. Leff and Dougall (TiPS 14, 110-112) have derived an equation, analogous to the (generally invalid) Cheng-Prusoff equation, which requires that the agonist concentration--effect curves have the form of a logistic function. In the final article of the series, Sebastian Lazareno and Nigel Birdsall consider this equation in the context of two related methods for analysing functional inhibition curves-a null method that makes no assumptions about the shapes of curves, and a curve-fitting method that provides an estimate of the antagonist Schild slope.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Drug Antagonism*
  • Kinetics