Pharmacology

Question 1

pharmacodynamics

Answer 1

what a drug does to the body

Question 2

pharmacokinetics

Answer 2

what the body does to a drug

Question 3

what is selectivity?

Answer 3

the ability of a drug to distinguish between different molecular targets within the body

Question 4

what do targets generally include?

Answer 4

targets that are unique to invaders and are not on eukaryotic human cells

Question 5

what regulatory proteins do drugs bind to to modify their function?

Answer 5

enzymes, carrier molecules, ion channels, receptors

Question 6

what does an agonist do

Answer 6

binds to a receptor to produce a cellular response

Question 7

what does an antagonist do?

Answer 7

a drug that reduces or blocks the actions of an agonist by binding to the same receptor

Question 8

what is selectivity dependant on?

Answer 8

the dose of a drug

Question 9

what are receptors made of?

Answer 9

protein, or glycoprotein, macromoles

Question 10

what are ligand-gated ion channels targeted by?

Answer 10

hydrophilic signalling molecules (fast neurotransmitters such as acetyl choline)

Question 11

what are G protein-coupled receptors also know as?

Answer 11

metabotropic receptors

Question 12

what are G protein-coupled receptors targeted by?

Answer 12

hydrophilic signal molecules (slow neurotransmitters such as acetyl choline, amino acids, peptide hormones)

Question 13

what forms ion channels?

Answer 13

glycoproteins

Question 14

what can ion channels be gated by?

Answer 14

chemical signals (ligand-gated), transmembrane voltage (voltage-gated) and physical stimuli (thermal and mechanical energy)

Question 15

classic example of ligand-gated ion channels?

Answer 15

the nicotinic acetylcholine receptor of skeletal muscle and neurones

Question 16

what does the nicotinic acetylcholine receptor look like?

Answer 16

consists of separate glycoprotein subunits that form a central ion conducting channel

Question 17

most cell surface receptors signal via what?

Answer 17

second messenger systems

Question 18

structure of G protein-coupled receptors? chemical

Answer 18

single polypeptide with extracellular NH2 and intracellular COOH termini

Question 19

what does the G protein-coupled receptor contain?

Answer 19

seven transmembrane a-helical spans joined by 3 intracellular loops

Question 20

what type of protein is a G protein? think location

Answer 20

peripheral membrane protein

Question 21

what does a G protein consist of?

Answer 21

3 polypeptide subunits (alpha, beta and gamma)

Question 22

what binding site does the G protein have and what does it allow?

Answer 22

a guanine nucleotide binding site in the alpha subunit that can hold guanine triphosphate or guanine diphosphate

Question 23

how are G proteins activated?

Answer 23

they are activated via agonist binding to the GPCR to which they preferentially couple

Question 24

what occupies the guanine nucleotide binding side in the non-active state of the G protein?

Answer 24

GDP

Question 25

what occupies the guanine nucleotide binding side in the active state of the G protein?

Answer 25

GTP. The alpha and beta subunits dissociate from each other

Question 26

what does the activation of the GPCR activate?

Answer 26

A G protein

Question 27

example of signalling that uses receptor kinases

Answer 27

insulin sigalling

Question 28

example of signalling that uses ligand-gated transcription factors

Answer 28

nuclear receptors and steroid hormones

Question 29

what is drug metabolism?

Answer 29

drug transformation by metabolism by the liver and other tissues

Question 30

what can drugs be excreted by?

Answer 30

in urine, faeces or bile

Question 31

what is bulk flow?

Answer 31

the movement of drugs around the body via the circulatory system

Question 32

what type of drugs are more likely to diffuse across the lipid bilayer?

Answer 32

lipid soluble drugs

Question 33

what are aqueous pores formed by?

Answer 33

aquaporin

Question 34

what type of drugs cross the cell membrane via passive diffusion?

Answer 34

lipid soluble drugs

Question 35

how do small molecules cross the cell membrane by facilitated diffusion?

Answer 35

via specialised carrier proteins. The binding of the drug on the protein causes a conformational change which allows the drug to diffuse across the membrane

Question 36

how do small molecules travel with active transport

Answer 36

via specialised carrier proteins

Question 37

what does saturation kinetics mean?

Answer 37

any process that has a limiting factor (limited number of specialised carrier)

Question 38

what are the principle sites of carrier mediated drug transport? (facilitated dissuion and active transport) 5

Answer 38

blood brain barrier, gastrointestinal tract, placenta, renal tubule and binary tract

Question 39

what type of drug is endocytosis used for?

Answer 39

transporting large drugs across the cell membrane (vitamin B12)

Question 40

what is the pKa?

Answer 40

the pH at which 50% of the drug is ionised and 50% of the drug is un-ionised

Question 41

can the non-ionised form of a drug permeate the membrane?

Answer 41

for many drugs, yes

Question 42

what compartments do weak bases accumulate in?

Answer 42

compartments with low pH

Question 43

what compartments do weak acids accumulate in?

Answer 43

compartments with high pH

Question 44

what type of pH do weak acids need to be absorbed?

Answer 44

low pH

Question 45

what type of pH do weak acids need to be absorbed?

Answer 45

high pH

Question 46

where does most oral drug absorption occur?

Answer 46

in the small intestine due to the large surface area

Question 47

what is the apparent volume of distribution? Vd

Answer 47

The extent to which a drug partitions between the plasma and tissue compartments

Question 48

what is the equation for volume of distribution?

Answer 48

Vd = Dose/ [drug]plasma

Question 49

what type of drugs find it more difficult to cross membranes and what does this do to the Vd?

Answer 49

hydrophilic and ionised drugs, Vd is closer to total body volume of water (41L)

Question 50

what type of drugs easily cross membranes and what does this do to the Vd?

Answer 50

lipophilic drugs. Vd is generally greater than total body volume (41L)

Question 51

what does a large Ka mean?

Answer 51

acid is strong

Question 52

what is the most abundant plasma protein?

Answer 52

albumin

Question 53

what is the effect of plasma protein binding on drug affinity?

Answer 53

it reduces the availability of the drug for diffusion to the drug target organ

Question 54

define drug metabolism ?

Answer 54

enzymatic conversion of the drug to another chemical entity

Question 55

what is the most important drug metabolising organ

Answer 55

the liver | but also the kidney, gut mucosa, lungs and skin

Question 56

when administered by the enteral (oral) route, metabolism in the liver...

Answer 56

REDUCES THE BIOAVAILABILITY OF DRUGS

Question 57

what is the bioavailability of the drug?

Answer 57

the systemic circulation of drug that is available

Question 58

where do the two phases of drug metabolism happen?

Answer 58

primarily in the liver

Question 59

where are hepatic drug-metabolising enzymes found?

Answer 59

embedded in the smooth endoplasmic reticulum of liver hepatocyes

Question 60

what changes in the drug can happen in phase 1

Answer 60

oxidation (most common), reduction or hydrolysis

Question 61

what do phase 1 metabolism reactions usually produce?

Answer 61

chemically reactive metabolites that can be pharmacologically active and or toxic

Question 62

what happens when people lack P450 activity?

Answer 62

higher drug plasma levels (adverse reactions)

Question 63

what happens when people have too much P450 activity?

Answer 63

lower drug plasma levels which reduces drug action

Question 64

what happens during phase 2 metabolism reactions?

Answer 64

drug combines with one of several polar molecules to form a water-soluble metabolite that can be readily excreted via the kidney

Question 65

what are the principal organs for drug elimination?

Answer 65

the kindneys, by renal filtration of blood plasma

Question 66

during renal filtration, what is reabsorbed into blood circulation by renal tubules?

Answer 66

water and most electrolytes

Question 67

what drug things are rendered polar by phase 2 metabolism and excreted in the urine?

Answer 67

drug metabolites that are not reabsorbed

Question 68

what is clearance? (CL)

Answer 68

an expression for the elimination