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2011-01-22 17:00:32
chapter two attractive forces between drugs receptors

week one
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  1. when a drug molecule moves so close to its receptor that the attractive force between them becomes great enough to overcome the random motion of the drug molecule, the drug binds to the receptor.
  2. the affinity of a drug for a particular receptor and the type of binding that occurs ins intimately related to the drug's what?
    chemical structure
  3. because 2 drug molecules cannot occupy the same receptor site at the same time, the drug with the _______ _______ will bind more readily to the receptor
    greater affinity
  4. affinity is expressed by its __________ ________ (___) which is the concentration of a drug required in solution to achieve ___% occupancy of its receptors
    • dissociation constant
    • KD
    • 50
  5. What happens when 2 drugs of equal concentrations are competing for the same receptor population?
    the drug with the greater affinity will bind with more receptors (and stimulate the receptor to cause an action) at any given instant; and a lower concentration of that drug will produce the same level of pharmacologic effect
  6. drugs with good affinity have greater _____ and require a _________ dose to cause a specific effect
    • potency
    • smaller
  7. _________ is related to the affinity of a drug
  8. drugs that have direct stimulatory effects on receptors are called what?
  9. a strong againist produces a significant physiologic response when a relatively _______ number of receptors are occupied
  10. the ability of an agonist to interact with a receptor and initiate a response is the function of its what?
    intrinsic activity
  11. when a small dose of a drug (agonist) produces a desired effect, the drug has good _____ and good _________
    • affinity
    • intrinsic activity
  12. true or false. a weak agonist must be bound to many more receptors to produce the same affect, so a musch larger dose of a weak agonist will be required to produce the desired affect. the drug has a lower affinity and/or lower intrinsic activity
    both statements are true
  13. a _______ ________ has affinity for the receptor, but very low intrinsic activity, and will never produce the same effect as a strong agonist or weak agonist even when all receptors are occupied.
    partial agonist
  14. the maximum response produced by a drug
  15. concept stating; a state of optimal receptor occupancy by the drug molecules; additional doses would produce no further beneficial effect
    ceiling dose
  16. as seen with the affinity of a drug for a particular receptor, the efficacy of a drug is also related to its ________________
    chemical structure
  17. The lowest dose of a drug that will produce a measureable response is called the what?
    threshold dose
  18. What is an example of a drug that reaches a plateau, efficacy, or maximal effect?
    acetaminophen, which has a ceiling dose of 1,000 mg for pain reliev, taking more will not produce greater pain relief, and may lead to toxicity
  19. the relative pharmacologic activity of a dose of a compound compared with a dose of a different agent producing the same effect
  20. __________ is related to the affinity of a drugy to its receptor, whereas _______ is related to the intrinsic activity of that drug once a drug receptor comlex is formed
    • potency
    • efficacy
  21. _________ is used to compare the effect of 2 drugs with affinity for the same receptor, to produce a given effect as a function of dose
  22. a drug that interferes with the action of an agonist but has no effect in the absence of an agonist and can be classified as receptor or nonreceptor _______
  23. ________ _________ prevent binding of agonist
    receptor antagonists
  24. What are 2 ways that a receptor antagonist can prevent agonists from doing their job?
    • they can bind at the active site (or binding domain) and prevent the binding of the agonist
    • they may bind to an adjacent site (overlapping with the agonist binding domain) and prevent the donfomational change required for receptor activation by an agonist
  25. true or false. Receptor antagonism can be reversible (competetive) or irreversible (noncompetetive)
  26. competetive receptor antagonism
    noncompetetive receptor antagonism
    • reversible
    • irreversible
  27. binds reversibly to the active site of tha agonist and maintains the receptor in its active conformation; it has affinity for a receptor, but no efficacy (cannot cause an effect)
    competetive antagonist
  28. how can the effect of a competetive antagonist be overcome?
    increasing the dose of the agonist
  29. the presence of a competitive antagonist reduces the ________ of the agonist
  30. binds to either the active site or to an allosteric (adjacent) site of the receptor and binds to the active site either covalently or with very high affinity, both of which are effectively irreversible
    noncompetetive antagonist
  31. true or false. an allosteric noncompetitive antagonist prevents the receptor from being activated even when the agonist is bound to the active site.
  32. the presence of a noncompetitive antagonist reduces the ________ of the agonist
  33. what is an example of a noncompetitive antagonist?