Pharmacodynamics L3 PDF

Homework - Five important subjects for five volunteers…………………..5 Marks - Drugs act as signals, and their receptors act as signal detectors. -Second messenger or effector molecules are part of the cascade of events that translates agonist binding into a cellular response The term agonist refers to...

Homework - Five important subjects for five volunteers…………………..5 Marks - Drugs act as signals, and their receptors act as signal detectors. -Second messenger or effector molecules are part of the cascade of events that translates agonist binding into a cellular response The term agonist refers to a naturally occurring small molecule or a drug that binds to a site on a receptor protein and activates it. 1- Signal amplification A characteristic of G protein–linked and enzyme-linked receptors is the ability to amplify signal intensity and duration via the signal cascade effect. Because of this amplification, only a fraction of the total receptors for a specific ligand may need to be occupied to elicit a maximal response. Systems that exhibit this behavior are said to have spare receptors. 1- Signal amplification For instance, about 99% of insulin receptors are “spare,” providing an immense functional reserve that ensures that adequate amounts of glucose enter the cell. On the other hand, only about 5% to 10% of the total β adrenoceptors in the heart are spare.