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Pharmacodynamics I
KYCOM Block 9
29
Pharmacology
Graduate
08/06/2013

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Cards

Term
what is the qualification of a drug that binds to a receptor
Definition
it must induce a biological response
Term
what drugs dont use receptors
Definition
diuretics and anesthetics
Term
where are drug receptors located
Definition
membrane proteins, cytoplasmic enzymes, extracellular enzymes, nucleic acids
Term
why are drugs/receptors specific
Definition
differnet tissues have receptors with different conformations that will only accept certian drugs
Term
what is the purpose of innert binding sites
Definition
drug binds a non-regulatory molecule (most commonly plasma membrane) and causes no changes but hitches a ride because it is lipid soluble and cannot travel in the blood
Term
how does innert binding sites affect drug effects
Definition
they ability or need of a drug to bind to them effects distribution and amount of the drug availiable
Term
explain the role of ionization in drug binding to receptor, what is the down side of needing to be ionized for bonding
Definition
when drug nears receptor various ionic bonds form but to participate the drug needs to be ionized first.

some drugs are already ionized

pH will alter non-ionized drugs
Term
what is the down side of a pre-ionized drug, what is the up side
Definition
it is water solube and will not distribute as well in the body because it cant get through membranes well (so no BBB or placenta crossing)

pH will not alter these as much
Term
where are nicotinic ACh receptors located
Definition
neuromuscular junction muscle end plate

autonomic ganglic

CNS
Term
what type of receptors are nicotinic ACh receptors
Definition
ligand gated ion channels
Term
what is the general function of a nicotinic ACh receptor, how does it work
Definition
depolarization of a cell

2ACh bind to 2 alpha subunts on recpetor and electrically open Na or K channels causing depolarization
Term
what is the down side of using nicotinic ACh receptors as a drug target, why
Definition
they can become desensitized if they have prolonged ACh exposure because the conformation of the receptor is altered so even if ACh binds there is no depolarization
Term
where are sodium channels located
Definition
excitable tisses like nerve, cardiac, skeletal muscle
Term
what type of channel are sodium channels, how do they work
Definition
voltage gated ion channels

resting state channel is closed and intracellular Na is low due to Na/K pump. depolarization of the membrane opens the channel allowing Na into the cell
Term
what drugs target Na channels, why
Definition
anesthetics to block nerve transmission by stopping Na influx
Term
where are g-protein coupled receptors located, describe their general structure
Definition
on almost all cells

heterotrimetric receptor with 7 transmembrane domains
Term
explain the process of a Gs or Gi protein once a ligand binds them
Definition
alpha subunit catalizes exchange of GDP to GTP and releases from beta and gamma creating alpha-GTP

alpha-GTP activates adenylyl cyclase then hydrolyzes GTP back to GDP

adenylyl cyclase converts ATP to cAMP

cAMP activates protein kinase A
Term
explain the process of a Gq protein once a ligand binds them
Definition
alpha subunit catalizes exchange of GDP to GTP and releases from beta and gamma creating alpha-GTP

alpha-GTP activates phospholipase C then hydrolyzes GTP back to GDP

phospholipase C releases IP3 and DAG from the phosphatidylinositol in the plasma membrane

IP3 activates Ca and calmodulin dependent kinase

DAG activates protein kinase C
Term
give examples of receptors Gs proteins are on
Definition
b-adrenergic

H2 histamine
Term
give examples of receptors Gi proteins are on
Definition
M2 muscrinic
a2 adrenergic
D2 dopamine
Term
give examples of receptors Gq proteins are on
Definition
a2 adrenergic
M2 and M3 muscerinic
5HT2 serotonin
Term
what agonists can activate a tyrosine kinase receptor
Definition
insulin, EGF, PDGF, HGF, ANF, TGF-beta
Term
describe the structure of a tyrosine kinase receptor
Definition
extracellular ligand binding domain

single transmembrane domain

intracellular binding domain with an INTRINSIC tyrosine kinase (means it is not activated by the receptor, it is ON the receptor)
Term
explain how a tyrosine kinase receptor works
Definition
ligand binds the extracellular domain, receptor dimerizes, tyrosine kinase signals within the cell
Term
what agonists can activate a cytokine receptor
Definition
growth hormone, erythropoetin, interferons
Term
explain how a cytokine receptor works
Definition
ligand binds, receptor dimerizes

JAK activates STATs

STATs signal transcription of genes
Term
agonists to intracellular receptors (6)
Definition
corticosteroids, mineralcorticoids, sex steroids, thyroid hormones, vitamin D, NO
Term
how does a steroid agonist activate a receptor
Definition
agonist goes through cell membrane to intracellular cytoplasmic receptor, receptor ligand complex travels to nucleus and signals transcription of genes
Term
explain how NO activates the receptor and changes within the cell
Definition
NO is generated in endothelial cells and diffuses into smooth muscle cells and reacts with gyanylyl cyclase which stimulates cGMP which activates protein kinase G which phosphorlyates to relax smooth muscle
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