Pharmacodynamics

seminar 4

what is pharmacodynamics

what the drug does to the body

what does the drug act on

receptors

what do receptors send to tell the cells what to do

signal transduction

what are the 4 types of receptors

\-ligand gated ion channels

\-g protein coupled receptors

\-enzyme linked receptors

\-intracellular receptors

when a ligand binds to a channel what happens to it

opens to allow ions to pass through the membrane

what is g protein coupled receptor also known as and why

seven transmembrane because it passes through the membrane 7 times

what are the subunits in g protein receptors

alpha beta and gamma

what is bound to the alpha subunit

GDP

when a ligand binds to a g protein receptor what happens at the subunit alpha

alpha goes to bind to GTP and beta and gamma left behind

what are the 3 types of g proteins

GS,GI,GQ

what does Gs stimulate

adenyl cyclase which turns into cAMP

What does Gi inhibit

adenyl cyclase so lowers cAMP

what does Gq stimulate

phospolipase C

What are the secondary messangers of plc

dag, ips

what does ip3 increase

ca2+

in enzyme linked receptors what is present

tyrosine

in enzyme linked receptors what happens when a ligand binds

conformation change which joins both receptors together then tyrosine regions get activated and converts ATP to ADP

What does the tyrosine pick up when ATP turns to ADP

phosphate

what attaches to the tyrosine phosphate

enzymes

what is intraceullar receptor located

completely inside the cell

what does the ligand have to cross before binding to intraceullar receptor

membrane

what do cells do when there is too much stimulation at the receptors

they can take the receptors out of the membrane

what happens if cells get weak signals

put more receptors in the membrane

what is ec50

concentration of the drug that causes 50% of the effect

if a drug has low ec50 what does it mean

it is more potent

what does a drug being efficaous mean

efficient so all recpetors full off drugs

what does anagonist do

blocks receptors

what happens to potency when there is an agonist as well as a comptetitive antagonist

reduced

what does and allosteric antagonist do

binds to another site of receptor and changes its active site so agonist cant bind to it

what is theraputic index

measure relative safety of a drug

what is the equation for theraputic index

dose of a drug that produces toxity in 50% population/efficiency of drug in 50% of population