Pharmacodynamics Flashcards
What is a receptor?
a macromolecule whose biological function changes when a drug binds to it
What is often the deciding factor of what binds to a receptor?
The specific shape of a receptor and drug
What are the strongest and weakest bonds between a drug and a receptor?
Covalent and van der Waals forces
What are the four types of receptors?
Ion channel
G coupled Receptor
Coupled to enzymes
Intracellular
How do ion channel receptors work and what is an example of one?
Receptor binds drug and allows for ion to flow through-fastest acting-acetylcholine
How do G-protein coupled receptors work and what is an example of one?
Once ligand binds to receptor, G-proteins send cascade of signals down (or inhibits signalling)-most common type of receptor-e.x. epinephrine
How do coupled to enzyme receptors work and give an example?
when the ligand binds, the receptors dimerize and then give signal, e.x. anti cancer drugs or insulin
What is the meaning of affinity?
attraction b/w drug and receptor
What is Kd?
the concentration of the drug that occupies 50% of receptors at equilibrium
What does a low Kd mean?
The drug won’t release as readily
What is an agonist?
affinity and intrinsic activity for the endogenous ligand, reversible
What is an example of an agonist?
Epinephrine, makes heart beat faster, when more is bound, the heart beats faster
What is an antagonist?
has affinity but no intrinsic activity, blocks endogenous ligands from binding, irreversible or reversible
How can antagonists be overcome?
Adding more agonists
What are spare receptors?
not all receptors are bound but max effect is produced
What is allosteric binding?
changes shape of receptors by binding to separate site
What is a partial agonist?
has affinity but not full intrinsic effect
What is an inverse agonist?
binds to a receptor but deactivates it
How is tolerance achieved?
decreased number of receptors or signal becomes reduced
What is upregulation?
block receptors and body makes receptors, this is why you can’t quit some drugs cold turkey
What is the rebound effect?
Too many receptors, body goes into overdrive the next time the body is exposed, happens with upregulation
What causes side effects>
continuation of drug action, acts of receptor in wrong organ or binds other receptors
What is a graded dose response curve?
Shows the percentage of a response at a certain drug concentration
What is the difference between potency and efficacy?
Potency: how much is required to elicit a response
Efficacy: response produced by a drug
