L11.1 Pharmacology Flashcards
explain the difference between pharmacodynamics and pharmacokinetics
pharmacodynamics: how drugs affect the body (affects receptors, enzyme targets, cell signalling, membrane channels)
pharmacokinetics: how the body effects drugs (the body absorbs, distributes, metabolises, excretes)
what is an agonist?
a substance that promotes a receptor-mediated biological response, often by competing with another substance at the same receptor
what is a receptor?
a molecular structure or site on the surface or interior of a cell that binds with substances such as hormones, antigens, drugs or neurotransmitters with specificity
on the molecular level, ____ bind to ____
on the molecular level, AGONISTS bind to RECEPTORS
explain what happens at a relatively low concentration of agonist
agonist binds to its receptors, causing physiological changes in the targeted cell.
obviously if there are no receptors on cells and tissues, there is no effect.
explain what happens at a higher concentration of agonist
many more of the receptors may be occupied at any given time, leading to a greater physiological effect.
there will be a concentration range that results in the optimal effect for your patient.
explain what happens when drugs are antagonists
drugs that are antagonists can also bind but do not activate the receptor. notice that, in this case (see ppt), the antagonist binds to the same area on the receptor as the agonist did earlier = this is called a ‘competitive antagonist’ for the receptor (competing with a natural agonist)
what are irreversible competitive antagonists?
a few drugs are irreversible competitive antagonists in which some of the receptors become permanently bound to receptors, at the same site as where the agonist binds.
when the agonists is applied, the maximum number of receptors available is less than 100% as some of them are permanently occupied by the antagonist.
how do G protein coupled receptors signal?
- receptor sitting vacant, G protein complex sitting inside the cell
- agonist binds to receptors activates it so it can interact with the G protein and it disassociates it, you have a unit that comes off B and Y stays and GTP is converted to GDP
- activation of other messengers
- GTP hydrolysis
(see lecture for more notes)
(see lecture for more notes)
T/F: some drugs can act without binding to a receptor
F
T/F: efficacy is the amount of drug needed to produce an effect
F
T/F: affinity is the attraction measured between two drug molecules
F
T/F: agonists are drugs which may bind to receptors to cause a physiological response
T
T/F: partial agonists have affinity for receptors, but partial efficacy
T
