Which of the following is true for receptor action of the drug: (A) An antagonist has both an intrinsic activity and affinity for receptor, (B) An antagonist has the affinity but no intrinsic activity for the receptor, (C) A paial antagonist has no affinity or intrinsic activity for the receptor, (D) Intrinsic action and affinity are not impotant for drug action
Answer is B. Ref-KDT 6/e p41 Intrinsic activity is a measure of the ability of a drug that is bound to the receptor to generate an activating stimulus and produce a change in cellular activity. Both agonists and antagonists can bind to a receptor.