Wed20October0612PM 4

Concerning drug dose and response:

True / False

Partial agonism implies low receptor affinity Correct

Intrinsic activity determines maximal response Correct

A plot of % response against drug concentration gives a sigmoid shape Incorrect answer selected

Maximal response occurs only when all receptor sites are occupied Correct

Antagonists must have a higher receptor affinity than agonists Correct

Explanation

Dose response curves are normally plotted as % response against LOG drug concentration. The resultant graph is sigmoid shaped.

A drug with high affinity and high intrinsic activity is an agonist. A drug with high affinity but no intrinsic activity will act as an antagonist, however, displacement of an agonist also depends on the relative concentrations of the two drugs at the receptor sites.

A maximal response may be achieved by activation of a small proportion of receptor sites (e.g. the neuromuscular junction).

Answer Statistics

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Average score: 67.38%

Times answered: 233