2016 self-assessment Treatment Lecture 2 PDF

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2016 self-assessment Treatment Lecture 2...

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Self-Assessment Questions (Lecture 2) Q1. Explain the difference between a receptor agonist and a receptor (competitive) antagonist and provide an example of each and the receptor with which they interact?

Q2. Theoretically, in the absence of other tissue influences, the proportion of receptors occupied by an agonist drug will depend on agonist concentration and its affinity for its receptor (strength of bonds formed): provide an equation for occupancy based on these factors?

Q3. In the context of agonist drug-receptor interactions which one or more of the following statements about the equilibrium (dissociation) constant KA for agonist drug A is (are) true: (a) as the numerical value of KA increases the proportion of occupied receptors at a given agonist concentration decreases (b) KA is numerically equal to the concentration of agonist when all the receptors are occupied (c) an agonist drug with a very small KA value (less than 10-9 M) has very high affinity for its receptor (d) when KA is a very small value, occupancy tends towards 100% (e) when applied at the same concentration an agonist with a smaller KA reaches a higher level of occupancy than one with a higher KA

Q4. Draw a graph to show the relationship between concentration (log value) of an agonist drug and size of response. What is the term used to define the potency of an agonist drug?

Q5. Which five factors influence the size of the actual response of a cell or tissue to an agonist drug? Provide a theoretical equation linking these factors together?

Q6 Which of the following statements about partial agonists is (are) true: (a) at a maximum concentration elicit the maximum response of which the tissue is capable in response to stimulation of the receptor population at which they act (b) reduce the response to a large concentration of a full agonist when given simultaneously (c) always possess lower efficacy than a competitive antagonist at the same receptor (d) always possess lower affinity than a full agonist at the same receptor (e) activate the same signal transduction mechanism as a full agonist at the same receptor Q7. Provide an example of a partial agonist drug and the receptor at which it interacts?

Q8. Which of the following statements is (are) true? The magnitude of the response of a tissue to a given concentration of an agonist drug: (a) depends on the number of receptors present (b) is the same for a full agonist as for a partial agonist (c) depends on the signal transduction mechanism to which the agonist’s receptor is coupled (d) depends on the equilibrium (dissociation) constant of the agonist drug (e) may be smaller in elderly subjects than in young adults Q9. Which one or more of the following statement(s) may account for desensitisation of response on chronic exposure to an agonist drug? (a) (b) (c) (d) (e)

reduction in the activity of enzymes responsible for metabolism of the drug increased number of cell surface receptors decreased affinity of the drug for the receptor enhanced activity of signal transduction mechanisms associated with the receptor enhanced activity of opposing physiological pathways

Q10 Which agonist drug is the most potent in the graph below, A, B or C and why?...