Pharmacology

Question 1

what is pharmacodynamics?

Answer 1

what a drug does to the body

Question 2

what is pharmacokinetics?

Answer 2

what the body does to a drug

Question 3

What do agonists do?

Answer 3

bind to a receptor to produce a cellular response

Question 4

what do agonists possess?

Answer 4

affinity and efficacy

Question 5

what do antagonists do?

Answer 5

bind to receptors and block activation by agonists

Question 6

what do antagonists possess?

Answer 6

affinity

Question 7

four processes that occur in drug disposition?

Answer 7

absorption
distribution
metabolism
excretion

Question 8

what form of drug readily diffuses?

Answer 8

unionised forms

Question 9

what is oral availability?

Answer 9

the fraction of drug that reaches the systemic circulation after oral ingestion

Question 10

what is systemic availability?

Answer 10

this is the fraction that reaches the systemic circulation after absorption (IV drugs have 100% systemic availability)

Question 11

factors affecting drug absorption?

Answer 11

solubility
chemical stability
lipid to water partition coefficient
degree of ionisation

Question 12

factors affecting GI absorption?

Answer 12

GI motility 
pH
blood flow
physicochemical interactions 
transporters present in membranes

Question 13

when is Css (steady state concentration) reached?

Answer 13

after 5 half lives

Question 14

what is steady state?

Answer 14

when drug administration is equal to drug elimination

Question 15

what is a loading dose and when is it given?

Answer 15

a loading dose is an initial higher dose of a drug, given at the start of treatment so it decreases the time taken to reach steady state

Question 16

what three reaction types occur in Phase 1 drug metabolism?

Answer 16

oxidation
reduction
hydrolysis

Question 17

what does Phase 1 drug metabolism aim to do?

Answer 17

make the drug more polar and add a chemically reactive group, so conjugation (phase 2) can occur

Question 18

what family of proteins mediate Phase 1 drug metabolism?

Answer 18

cytochrome P450 Monooxygenases

Question 19

what happens in the monooxygenase P450 cycle?

Answer 19

drug (RH) enters and joins with P450
drug combines with one O of Oxygen, to produce ROH
other oxygen combines with H+ to form H20

Question 20

what does Phase 2 drug metabolism aim to do ?

Answer 20

add an endogenous product, which is called conjugation, and inactivate the drug

Question 21

what is glucoronidation?

Answer 21

transfer of glucoronic acid to the substrate

Question 22

what drugs can be excreted by glomerular filtration?

Answer 22

unbound drugs

Question 23

what facilitates tubular secretion?

Answer 23

organic anion transporter (against electrochemical)

organic cation transporter (with electrochem)

Question 24

in tubular secretion, what influences drug excretion?

Answer 24

concentration (pH) of urine

Question 25

what pH of urine favours excretion of acids/bases?

Answer 25

alkaline favours excretion of acids | acidic favours excretion of bases

Question 26

direction of Na concentration and electrochemical gradient

Answer 26

IN | IN

Question 27

direction of K concentration and electrochemical gradient

Answer 27

OUT | IN

Question 28

what is the equilibrium potential for EK?

Answer 28

- 100mV

Question 29

what is the equilibrium potential for ENa?

Answer 29

+60mV

Question 30

positive feedback is shown by what channels?

Answer 30

sodium

Question 31

negative feedback is shown by what channels?

Answer 31

potassium

Question 32

what causes the refractory period?

Answer 32

Na+ channels enter a non conducting state when maintained depolarisation occurs

Question 33

where is sympathetic outflow from and what is it called?

Answer 33

T1-L2, thoracolumbar

Question 34

where is parasympathetic outflow from and what is it called?

Answer 34

CN 3, 7, 9 and 10 | craniosacral

Question 35

in sympathetic, what are the two neurotransmitters and the receptors they work on?

Answer 35

acetylcholine (cholinergic) | Noradrenaline (adrenergic)

Question 36

in parasympathetic, what is the neurotransmitters and the receptors it works on?

Answer 36

acetylcholine (cholinergic)

Question 37

what type of channels are activated in effector cells, in the sympathetic? what activates them?

Answer 37

g protein coupled adrenoreceptors, noradrenaline

Question 38

what type of channels are activated in effector cells, in the parasympathetic? what activates them?

Answer 38

g protein coupled muscarinic acetylcholine receptors, acetylcholine

Question 39

in g protein coupled receptors, what does the receptor consist of?

Answer 39

7 transmembrane spans, joined by 3 extracellular and 3 intracellular loops

Question 40

in g protein coupled receptors, what does the g protein consist of?

Answer 40

alpha, beta and gamma subunits | a guanine nucleotide binding site for GTP/GDP

Question 41

how do g protein coupled receptors work?

Answer 41

- alpha subunit binds to GDP - agonist binds to the receptor, causing the g protein to also - GDP->GTP in the guanine nucleotide binding subunit - g protein dissociated to alpha and beta/gamma subunits, with the alpha combining to the effector (with GTP attached) - this modifies the effector TO INACTIVATE.. - alpha subunit catalyses GTP->GDP +Pi, so the signal is turned off - g protein detaches from the effector and reassembles

Question 42

steps of cholinergic transmission and degradation

Answer 42

- choline is uptaken - ACh is synthesised, via CAT, which is then stored in vesicles - depolarisation via an AP occurs - Ca2+ influx, causing release of ACh - ACh acts on receptors to cause a cellular response degradation of ACh - ACh -> choline and acetate by AChE - choline is re uptaken and reused

Question 43

what receptors does ACh act on?

Answer 43

nicotinic ACh receptors (ligand gated ion channels) | g protein couples muscarinic ACh receptors

Question 44

3 types of g protein couples muscarinic ACh receptors and their effects

Answer 44

M1 Gq - stimulation of phospholipase C, causes increased acid secretion in the stomach M2 Gi - inhibits adenylyl cyclase, decreases HR M3 Gq - stimulation of phospholipase C, relaxes vascular smooth muscle and increases saliva production

Question 45

steps of noradrenergic transmission and degradation

Answer 45

- synthesis of NA and storage in vesicles - depolarisation via an AP - Ca2+ influx, which causes release of NA - activation of G protein couples adrenoreceptors - reuptake of NA

Question 46

in presynaptic, what happens to NA?

Answer 46

U1 uptakes it | metabolised to MAO

Question 47

in postsynaptic, what happens to NA?

Answer 47

U2 uptakes it | metabolised to COMT

Question 48

4 types of G protein coupled adrenoreceptors and their effects

Answer 48

beta 1 Gs - stimulates adenylyl cyclase, increases HR and force beta 2 Gs - stimulates adenylyl cyclase, relaxes bronchial and vascular smooth muscle alpha 1 Gq - stimulates phospholipase C, contracts vascular smooth muscle alpha 2 Gi - inhibits adenylyl cyclase, inhibits NA release

Question 49

what do presynaptic autoreceptors do?

Answer 49

act as a negative feedback system increased neurotransmitter in the synaptic cleft is sensed by autoreceptors they halt Ca2+ influx into the cell

Question 50

effects of agonist and antagonist on function of presynaptic autoreceptors?

Answer 50

agonist decrease release by autoreceptor (more neurotransmitter) antagonist increase release by autoreceptor (less neurotransmitter)