Lecture 53 - pharmacodynamics Flashcards
How do drugs produce effects in the body?
*big concept
biochemically and physiologically
summarize 3 ways a drug produces changes
- drug binds to a target molecule
- change in physical property
- chemical or metabolic change
T/F: drugs do not create new cell effects/actions
TRUE
define ligand
something that binds a receptor
where are drug receptors located
on or within cell surface/cytoplasm
Describe ionotropic receptors
ion channel for Na+, K+, Cl-
fast-acting
voltage- or ligand-gated
describe metabotropic receptors
no pore/channel
secondary messengers (G-coupled)
slow
what are the 4 major receptor types
- ion channel
- G-protein coupled receptors
- enzyme-linked
- intracellular
What receptors are the target of over 50% of drugs
G-protein coupled receptors
describe Gs
- activate adenylyl cyclase
- increase cAMP
- generate response
describe Gi
- decrease AC and cAMP
- inhibit ion channels
describe Gq
- activate PLC
describe enzyme-linked receptors
- extracellular binding sites
- receptor autophosphorylates
- EX: insulin. growth factors
summarize how intracellular receptors work in 5 steps
- steroid hormone diffuses through plasma membrane and binds receptor
- receptor-hormone complex enters nucleus
- receptor-hormone complex binds specific DNA region
- binding initiates transcription of bound gene
- mRNA directs protein synthesis
define drug activity (intrinsic efficacy)
ability of a drug to have a response
define drug affinity
force of attraction between drug and receptor
define drug selectivity
drug’s ability to affect a particular receptor population in preference to others
define agonist
binds to a receptor and causes a response
“mimetic”
define partial agonist
binds and activates the receptor
results in partial response
define antagonist
binds to receptor and does not cause a response
“blocker”
what is a competitive antagonist
It looks like the drug and binds at the same site
what is a non-competitive antagonist
binds somewhere else and changes conformation so agonist cannot bind
why is is preferred to take a highly selective drug
binding to only one receptor decreases chance of side effects
define potency
amount of drug needed to produce a response
dose-response relationship
the more drug you give, the more response you get
T/F: a high-potency drug will have the desired response when greater concentrations are achieved
FALSE
what is the therapeutic index?
the relative safety of a drug
