Essential Pharmacology Flashcards
Can the same receptor on a cell be coupled to different responses?
Yes
What should the ligand be in order to bind to an intracellular receptor?
Hydrophobic/lipid soluble
Give an example of a ligand that is lipid soluble…
Steroid hormones
What do intracellular receptors often regulate?
Rate of transcription, often known as transcription factors
What are the 4 types of plasma receptors?
- Ones with ion channels (ionotropic) - ligand gated channels
- Receptors that act and enzymes
- Receptors that regulate enzymes
- G protein coupled
So what is the point of receptors?
They enable the specificity of the action of different transmitters and hormones
What is the largest class of plasma receptors?
G protein coupled
What happens when a G-protein receptor is coupled to adenylyl cyclase
It increases cAMP which activates PKA (if unbound will do the opposite)
What happens when a G-protein receptor is couples to Phospholipase C?
Produces DAG which activates PKC
AND
IP3 which releases Ca2+ ions
What are PKA and PKC used for?
For phosphorylation - therefore regulate a host of cell proteins
How do drugs act?
By interacting with a binding site - a receptor
What happens the more drugs that bind to the receptors?
There is a bigger response until all of the receptors are filled and then increasing drug level doesn’t do anything…
What is efficacy?
Determines how good a drug is at activating a receptor - drugs can partially activate receptors
What is affinity?
How well the drug binds to the receptor
What is the affinity and efficacy of a full agonist?
High affinity
High efficacy
What is the affinity and efficacy of a partial agonist?
High affinity
Low efficacy
What is the affinity and efficacy of an antagonist?
High affinity
Little to no efficacy
Can one transmitter act on many receptor sub types? Give examples, do they always act like this?
Yes
Ach - agonist acts on all cholinergic receptors like nicotinic and muscarnic
Noradrenaline - agonist acting on all adrenergic receptors - alpha 1 an 2 and beta 1 an 2
But transmitters can also be selective
