how do drugs work Flashcards
what is the plasma mebrane
a selectively permeable barrier between the extracellular environment and the cytosol
what are the components of the plasma membrane
Na+, K+, Ca2+, Cl-, Glucose
is there a similar amount of calcium inside and outside the cell
no
is there more calcium inside or outside the cell
outside
how do drugs work
once they arrive at the proper site of action, they bind to receptors
where are receptors usually located
on the outer membrane of cells
what does the binding of drugs to receptor do
it can sometimes trigger activation of enzymes located within the cell
what type of proteins are receptors usually
integral membrane proteins at the plasma membrane, can also be found inside the cell
what do receptors do
recognise and bind to specific chemicals which invokes response
can receptor numbers change
yes they can be increased (up-regulation) or decreased (down-regulation)
why would up regulation or down-regulation occur
in response to a chronically low or high concentration of the agonist to optimise sensitivity
what two properties do agonists have
- affinity - strength of binding to receptor
- efficacy - intrinsic activity
what does efficacy do
induces a conformational change in the receptor and activation of a response
what property does an antagonist have
has affinity
what does an antagonist do
blocks the receptor
why can’t antagonists activate a response
they don’t have efficacy
examples of antagonists
anti-histamines, beta-blockers
when does down-regulation occur
in response to chronically high concentration of ligand.
what does down-regulation do
decreases the sensitivity of the cell response to frequent or intense stimulation
