Pharmacodynamics Flashcards
What is the many type of drug target in the body
Enzymes then GPCRs
What unit is used to measure drug concentration
Molarity
What must a ligand posses in order to bind to a receptor
Affinity
What is intrinsic efficacy
The ability to activate a receptor by causing a conformational change
What type of ligand results in an intrinsic efficacy
Agonist
What is efficacy
The ability of a ligand to cause a response
Why don’t antagonists cause a response
They possess no intrinsic efficacy
How is drug receptor binding measured
Using radio ligands
What is Kd
The drug concentration at 50% bound receptors
What is Kd a measure of
Affinity
Why is it good for drugs to have a high affinity for receptors
Can use smaller tablets
What graph shape do log[drug] vs bound receptors show
Sigmoidal
What is EC 50
Effective concentration giving 50% response
Define concentration
Known concentration of drugs at a site of action
Define dose
Concentration at site of action unknown
What is potency
Concentration giving 50% of the maximal response
What does potency depend on
Affinity and intrinsic efficacy
What allows for a maximal response without 100% of receptors bound
Spare receptors
Why are there spare receptors
Due to application of signal transduction pathway
Why do we have spare receptors
Increase sensitivity (increase/decrease coco of ligand that causes a response) so allows for responses at low drug concentration
How do receptor numbers change with low activity
Increase (up regulation)
How do receptor number change with high activity
Decrease (down regulation)
What is a partial agonist
Agonists with lower intrinsic efficacious so can’t result in a full response
When can partial agonists act as a antagonist
When there are high levels of full agonist
