Bio Balance and DSS Systems & Software Technologies Ltd. complete development of a prototype program that calculates the high and low affinities for Bio Balance's two-state, biophysical model for the initial receptor response.


The Prototype can assist researchers with the analyses of their dose-response data. This should be particularly useful for dose-response data that display desensitization or down-regulation in response to continued or prolonged application of a stimulating ligand, agonist or drug.


Prototype Download (6.7 MB - file type "*.exe" - download to a new folder labeled "Program_files" then run the installation program by double clicking on the setup file, which you downloaded. The download should take between 5-60 minutes depending on the speed of your connection and computer.)


The Prototype Program is designed to work with PC compatible computers running Excel 2000 or better. It is designed to take an Excel data sheet of dose-response type data and fit it to the equation for RH (see below).


The Prototype fits the KDH and KDL values to a set of dose-response data in an Excel data sheet. It allows the user to select starting values for the dissociation constants KDH and KDL. The initial high and low affinity receptor states, RH and RL, values are set arbitrarily to 100, but can also be changed by the user. After the program runs, it will display a plot of the fit to the data and a table of values for the fit.


To download an example of the Excel test data sheet for use with the Prototype use this link:




This is similar to most other two-state models with R and R* states corresponding to inactive and active receptor states except that this model relates the response to a fundamental equation for physical equilibrium, which can be solved for the net shift in the original equilibrium, RH,



Where RH and RL represent the amount of unperturbed receptor existing in initial high and low affinity states respectively, and  represents the concentration of the binding drug or ligand. With the dissociation constants, KDH and KDL, for the high and low affinity binding, this equation has been shown to accurately model the dose-response behaviors for agonists with and without antagonists in a wide variety of drug-receptor systems (see EXPERIMENTAL VERSUS CALCULATED DOSE-RESPONSE CURVES below).


To see the derivation of the equation for RH above, visit the following link to the Graphics section:


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