Instructions: Look at the dose‐response plots below and interpret which scenario is most likely for each. Learning Goals: To gain experience analyzing dose‐response relationships and determining how different types of ligands affect dose‐response graphs. Please complete the online exercise. OPTIONAL‐Please participate in the online discussion forum.
5.3 Occupancy Theory The pros and cons of the Clark model video Please watch the online video (8 minutes 42 seconds). A condensed summary of this video can be found in the Video summary page. OPTIONAL‐Please participate in the online discussion forum.
Determining an EC50 value Background: The EC50 value for an agonist occurs at the inflection point of a sigmoidal curve. Instructions: Read the passage below on the easiest method for determining an EC50 from a set of experimental data. Then, use the data points to estimate the EC50 value of the ligand. Learning Goals: To understand how to manipulate ligand‐response data and gain quantitative information on the ligand. Data points fitting a sigmoidal relationship are much more difficult to manipulate than linear data. Unfortunately, software packages that best handle sigmoidal data are not freely available. In the absence of a commercial data processing software package, linearizing ligand‐response data is a viable option. Because Clark's occupancy theory can be modeled with what is essentially the Michaelis‐Menten equation, the ligand‐response data for many receptors can be linearized with what amounts to the Lineweaver‐Burk equation. The linearized, double‐reciprocal version of Clark's equation is shown below.