Drug Receptor Interactions 2 Flashcards
What is the equation for the response?
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What are spare receptors?
The extra receptors if less than 100% of receptors are required to evoke a maximum response
What is efficacy?
Max response achievable from a drug. This can be obtained by occupying less than 100% of the receptors
What is the difference between efficacious drugs?
very efficacious drugs will require to occupy few receptors to give a response than less efficacious
What are some of the features of partial agonists?
- Low efficacy so never produce max response - They can decrease the response of a full agonist as they give a smaller response than if all full agonists were bound
What is a competitive antagonist?
A drug that binds reversibly with receptors to form a complex but this complex does not evoke a response
What is the equilibrium dissociation constant for an antagonist?
K(A). It is the concentration of antagonist that makes is necessary to add twice as much agonist to produce response
What direction is a Log-Dose response curve displaced by a competitive antagonist
To the right as more agonist is needed to required to produce max response, however the linear sections remain parallel
What is the Schild Equation
Where r is the ratio by which D must be increased to overcome competition by A
What is pA(2)
A way of comparing the affinity of an antagonist. It is equal to -log(base10) of K(A)
What are irreversible competitive antagonists?
The bind to the receptor site but dissociate so slowly that it is basically irreversible. Therefore the effects of these are not reversed by adding more agonist
Describe the effects of the irreversable competative antagonists on the log Dose-response curves and this effect over time
The curve is decreased. And over time this curve decreases more as agonists come on and off receptors this allows more antagonists to bind.
Describe some of the features of allosteric modulators
- Bind to allosteric sites which are regulatory - Modify efficacy or affinity - Potentiate or inhibit
Name an example of allosteric modulator
Non competitive antagonist. They work by blocking the access of the agonist to its binding site through steric hindrance
What is an inverse agonist?
This dampens the response. They bind to the active sire and cause a reduction in the activity of the drug
What are the effects of antagonist on an inverse agonist
