Pharmacology Flashcards
What is a receptor?
A molecule that binds to another molecule in order to initiate or modulate signalling or effector activity within a cell
What is a ligand?
A molecule that binds to a receptor
What is a binding site?
Area on a receptor that a ligand binds to
What are the categories of receptors?
Ligand-gated ion channel, G-protein coupled, kinase-linked, nuclear
How does a ligand-gated ion channel receptor function?
Binding of a ligand regulates the opening of the ion channel and thus the flow of ions in or out of the cell.
How does a G-protein coupled receptor function?
The receptor, consisting of 7 transmembrane segments, is bound to a G-protein. Binding of an agonist activates the G-protein, which then leads to various effector functions such as channel or second messenger cascade effects
How does a kinase-linked receptor function?
The receptor is dimerised by a ligand, activating its enzymatic properties. It is then able to phosphorylate selected proteins, which leads to changes in gene transcription and protein synthesis.
How does a nuclear receptor function?
A receptor is activated, often by dimerisation and two molecules of ligand, and alters gene transcription and protein synthesis
How does one determine the right dose of a drug?
Enough to do some good, and not enough to do much harm. The range of appropriate doses is termed the therapeutic wiindow
What can lead to a narrow therapeutic window?
If the benefits provided by the drug and the side effects act via the same mechanism. If they act via different mechanisms, the therapeutic window is much wider
What is the difference between a partial and a full agonist?
A full agonist stimulates a maximal response. In contrast, a partial agonist has a smaller pharmacological efficacy, produces a smaller maximal response
