Overview of Techniques for Measuring Receptor-Agonist Interactions Through Their Physiological Effects
There are many ways to measure physiological effects of receptor-ligand interactions. Methods which may be employed for the measurement of physiological effects due to receptor-agonist interactions range from conscious live animals, through organ and tissue preparations at various levels of isolation, through cells in cultures and isolated membrane preparations, to isolated receptor-effector systems at the molecular level. Isolated organ and tissue preparations have been extensively used for measuring effects due to receptor-agonist interactions. Tissue slices, cell cultures, and membrane preparations further reduce potential problems with distribution and metabolic alteration of the agonist. For example, one might measure the increase in concentration of cyclic AMP in a cell culture preparation as compared with a change in behavior in a whole-animal preparation. Isolated receptor-effector systems can sometimes be analyzed at the molecular level. If one measures the activity of an isolated enzyme, which is regulated by calcium-calmodulin, one has a receptor-effector system fully at the molecular level.