Drug Receptor Interactions 1 Flashcards
What is a receptor?
A specialised, localised protein whose role is to recognise stimulants and translate this event into an activation of the cell
Define an agonist
A molecule that binds to a receptor causing a conformation change eliciting a response
Define an antagonist
A molecule that binds to a receptor, doesn’t cause a conformation change so doesn’t elicit a response
What are the proteins that are commonly given the term receptors
Enzymes, Carrier Molecules (transporters), Ion channels, Neurotransmitters, hormone or local hormone receptors
What is the Law of Mass Action
The rate of the forward reaction is proportional to the rate of the reverse reaction
K2/K1 is what?
Estimate of the affinity
What is the equation for the Law of mass action applied to pharmacology
What does the equilibrium dissociation constant K(D) - small D represent
Represents the concentration of drug required to occupy 50% of the receptors at equilibrium. So it is a measure of the affinity of a drug for a receptor
What is the purpose of plotting a specifically bound graph in log
It allows for easy manipulation of data
What is the difference between specifically bound and non-specifically bount
Specifically bound will have a higher affinity and be harder to displace while the non-specifically bound will have a lower affinity.
What is the Hill Langmuir equation? and why is it used?
It is used to determine the concentration of drug needed to occupy a certain proportion of receptors.
What is another way to express the equilibrium dissociation constant K(D) and what is it?
pD2, It is the -log10 of drug that occupies 50% of the receptors at equilibrium.
If the pD2 is big or the KD is big, what does this mean?
Greater the pD2 then it has a greater affinity however if KD is great then it has a lower affinity.
