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Flashcards in WHOLE MODULE Deck (375)
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1
Q

What is the relationship between Kd and DR

A

Inverse

2
Q

What does an agonist have to be able to do in order to be classed as a full agonist

A

Induce the max repsonse of the tissue

3
Q

What can be said about the ion turnover of facilitated transport proteins

A

It is high

10^2 - 10^3 ions / s

4
Q

what is the name of the transporter which allows Na to enter TAL cells

A

NKCC2

5
Q

What type of cells are increase in rheu arth patients

A

Th1 cells

6
Q

Does Kd always equal EC50

A

No

7
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Difficult to incorporate ligand fue to high mass

A

Disad I 125

8
Q

What is occupancy dependent on

A

Drug concentration

9
Q

What is meant by aspiring being a suicide inhibitor

A

Permanently binds to XOZ

10
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Biological act of the ligand can be reduced

A

Disad I 125

11
Q

Act of macrophages as a result of autoimmune resp leads to synth of which two pro inf mediators

A

Interleukin-1 (IL-1) and tumor necrosis factor a (TNF-A)

12
Q

What occurs when calcineurin is activated

A

Activation leads to removal of phosphate groups and act of TF NFKB that promotes transcription of pro-inflam chem/cytokines

13
Q

NAPQI toxic intermediate A or P

A

Paracetamol

14
Q

What is meant by physiological antagonism

A

When two or more drugs interact with opposing actions - or act through different transduction machinery

15
Q

What is the difference between the nernst and goldman equations

A

Nernst used to calc eqbm pot wherease goldman used to calculate the membrane potential

16
Q

Define specificity

A

the attribute that a drug will preferentially bind to one type of receptor over another

17
Q

What can usually be said of the metabolism of a drug which is rapidly absorbed from the drug

A

Metabolism will be fast

18
Q

Describe how allosteric modifications aid in acid extrusion

A

Protons other than the one being transported bind to the NHE protein and cause a conformational change that results in an increased rate of transport at higher protein concentrations

19
Q

Give examples of medications given directly to the skin

A

Nicotine patches, chronic pain treatments such as fentinon

20
Q

Who developed the patch clamp technique

A

Nehr and Sakman

21
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

High specific activities can be obtained

A

Ad H3

22
Q

Would a drug with a higher Kd be more or less potent

A

Less

23
Q

How can we classify facilitated transport proteins

A

Uniporters, symporters and antiporters

24
Q

What is the benefit of biologicals in treatment of autoimmune disease and how can this cause problems

A

More longer lasting (longer half life) and fewer off site effects, but can dampen down the immune system so more susceptible to infection

25
Q

How many TM domains of VGKC

A

6

26
Q

How many transmembrane domains does a GPCR have

A

7

27
Q

Where is AE1 predominantly found - what is its main role

A

Red blood cells

Creates the Cl-/Hamberger shift

28
Q

Explain how particle size influences a drugs effectiveness

A

Larger particle sizes as are found in non-branded medication will more often be metabolised so less of that drug will have an effect. Smaller particles are more liekly to enter the blood stream

29
Q

What prevents an acid from being absorbed into cells once it is dissociated

A

Acid group will have a negative charge and the cell is also negatively charged so will be unable to cross the membrane

30
Q

What is the Cl/HCO3 exchanger primarily involved with

A

Involved in acid loading

31
Q

What is they symptom patter of expression in rheum arth

A

Symmetricle (both sides of body effected)

32
Q

By what mechanism is Ca kept low

A

Ca/Na exchanger and the CaATPase

33
Q

Give an example of a drug injected into the CSF and how is this benificial

A

Epidural - pain relife given during labour - means that the patient isnt required to be unconscious

34
Q

What would you see in the conc-resp curve for an agonist as you increase the conc of antagonist present in the system

A

Parallel rightward shift in the curve due to a higher concentration being required to elicit the same percentage response

35
Q

Give an example of physiological antagonism

A

NAdr raises arterial BP by acting on the heart and peripheral blood vesssles while histamine acts to reduce arterial BP by causing vasodilation

36
Q

How are some inflammatory mediatiors involved in homeostasis

A

PG A2 is a vasodilator, PGD2 inhibtis platelet agg and PG F2 is a bronchoconstrictor

37
Q

What approximation can be used when plotting B/F against specific binding

A

Free ligand, F is the same as the concentration of the added ligand

38
Q

Doubling the concentration of protons in solution would equate to a pH change of

A

0.3

39
Q

What does NHE rely on

A

Inward Na gradient

40
Q

How are some inflammatory mediatiors involved in the perception of pain

A

Some PGs increase the sensitivity of nociceptors to painful stimuli

41
Q

How many TM domains of a VGNC

A

24

42
Q

What is the preferred method for drug administration and why

A

Oral as tablets

Convenient

43
Q

Why is COX2 a desireable target for NSAIDS

A

Inhibiting its activity will have less impact on homeostasis, something which accounts for the side effects in COX1 inhibitors

44
Q

What type of transport protein has the highest turnover of ions

A

Channel proteins

45
Q

T/F
When combined with the gradient created by the Na/K ATPase the gradient created by the Ca/Na exchanger is equal to the Na gradient

A

True

46
Q

A or P - reduced risk of colon or rectal cancer

A

Aspirin

47
Q

What are NSAIS prescribed for genrally

A

Musculoskeltal pain

48
Q

What is the name of the molecule that is converted into inflammatory mediations
Where is this molecule found

A

Arachidonic acid is produced from phospholipids from the membrane of the cell by phospholipase A2

49
Q

What is the contribution of the Na/K ATPase to the Vm in MV

A

3mV

50
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Spec labs and equiptment required

A

3H disad

51
Q

What accounts for the differences between COX1 and CO2 isoforms

A

COX1 has a bulky isoleucine at a position the COX 2 has a smaller valine, so channel in COX2 is wider

52
Q

If only the K+ chanells are open why isnt Vm ~ Ek

A

Influence of other ions

K leak channels (let Na through also)

53
Q

What is the other name given to co-transporters

A

Symporters

54
Q

How can we manipulate compartment pH in overdose situations

A

To prevent absorption of drugs that are weak acids in patients that have overdosed NaHCO3 is administered to neutralise the pH

55
Q

Current measured in patch clamp technique is relative to

A

The ref electrode

56
Q

Example of a ligand gated ion channel

A

nAchR

57
Q

What happens once a drug that is a weak acid is absorped into the blood

A

pH of the blood is roughly neutral so more of the drug will dissociate

58
Q

EC [Cl]

A

150 mM

59
Q

What consituent forces make up the electrochemical gradient

A

Potential difference and concentration

60
Q

Define equillibium potential

A

The Vm where there is no net movement of ions across the membrane and thus no current is meaured

61
Q

What do microsomal enzymes act on

A

The inactive, uncharged drug once it has crossed the plasma membrane

62
Q

What are the active sites of COX enzymes

A

Peroxidase AS and cycloxygenase AS

63
Q

T or F Rheumatoid arthritus only presents around ages 40-60

A

F - can present in young adults and children too

64
Q

What is meant by effiacy

A

The ability of the drug receptor complex to form an active complex which can induce a response in the target cell

65
Q

IC [Ca]

A

2 mM

66
Q

T or F
Polar molecules can dissolve freely in lipids due to their ability to interact with charged groups on the molecules thus enabling them to penetrate cell membranes freely

A

False

Non polar/uncharged molecules can freely penentrate cell membranes, polar molecules can not

67
Q

Is an exchange protein synonomous with an antiporter

A

Yes - same thing

68
Q

IC [Na]

A

15 mM

69
Q

What is recovery in Ph in a buffered system due to

A

Acid loading and extrusions

70
Q

Other than B2 ad agons what is the most common asthma treatment

A

Glucocorticoids

71
Q

A or P only competivie inhib

A

Paracetamol

72
Q

How do NSAIDS prevent conversion of arachiodonaic acid to infl mediators

A

Block the channel in the COX enzyme preventing arachidonic acid entering

73
Q

Give an example of a non comp antagonist

A

Dihydropyridines bind to and block Ca channels rather than the receptor (which is activated by Nadr)

74
Q

What is the role of the chemoreceptor trigger zone in the brain and how can this lead to some side effects of drugs

A

CTZ is the area at the base of the brain responsible for nausea and the vomitting reflex
Some receptors can bind to these receptors and thus inappropriatly cause the this response

75
Q

Upon what principle does buffering rely on

A

Ability of amino acids to act as proton acceptors/recievers

76
Q

What three factors lead to est of the resting potential

A

Selectively permeable membrane
Unequal distribution of ions
Unequal distribution of physical forces (diffusion and electrochemical gradient)

77
Q

How many subunits to the Na/K ATPase

A

2 alpha and 2 beta

78
Q

3 As of NSAID effect

A

Anti-inflammatory, antipyretic, analgesic

79
Q

How do large molecules pass the cell memebrane

A

Endocytosis

80
Q

Agonists will have what degree of efficacy

A

High

81
Q

What molecules do NSAIDs prevent the synthesis of

A

Prostaglandins and thromboxanes

82
Q

How many IC domains does a nuclear recepotr have, why?

A

None

Found IC

83
Q

Define Ec50

A

The drug concentration at which the response is 50% of the maximal response

84
Q

What fluid compartment would contain the highest conc of PO4(2-)

A

ICF

85
Q

What ould be the expected efficacy value for a full agonist

A

1

86
Q

Explain how inverse agonists work

A

Some receptors can adopt an active conformation without the presence of an agonist - inverse agonists bind to these receptords and stabilise their structure reducing and constitutive activity

87
Q

How many ions can a channel protein hold at one time

A

Many

88
Q

What sort of pH stimulates NHE

A

Acidic

89
Q

Describe what happens in the induction phase of the immune response

A

APCs associate with CD4+ and CD8+ cells and act. Act CD8+ become Tc cells and kill cell. Act CD4+ begin to produce IL-1 leading to act and prolif of the Th1 cells. B cells also activated, transform to plasma cells and begin creating antibodies

90
Q

Non competitive antagonism?

A

Do not compete with the agonist but block some steps in the process between receptor and resposne

91
Q

Rate of excretion is INDEPENDENT OF _____ AND IS DETERMINED BY _____

A

Concentration

Metabolism

92
Q

What is the broad group of inhibitors of the Na/K ATPase

A

Cardiac glycosides

Ouabain digoxin

93
Q

How do small molecules and ions move into and out of the cell

A

Via facilitated diffusion through transport proteins

94
Q

How would the results of a radioligand binding assay what could be done

A

Bound ligand / Free ligand AGAINST specific biding

B/F against specific binding

95
Q

How do low and high concentrations of ryanodine influence one of these Ca channels

A

Low concnetrations activate

High concentrations inhibit

96
Q

Since NKCC2 relies on the inward gdt of Na what would occur if Nai was increased

A

Transepithelial osmotic gradient reduced/dissipated so Na and Cl reabsorption is inhibited

97
Q

What is meant by receptor reserve

A

More receptors present than the tissue needs to cause a maximal response

98
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Long half life

A

Advantage of 3H

99
Q

How does the Na/K ATPase contribute to the Vm

A

Directly and indirectly

100
Q

What affects drug absoption

A

Method of admin, size/Mr, lipid solubility, carrier mediated transport, pH/ionisation state

101
Q

What is the TAL reponsible for

A

reab of Na and CL

102
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Safer to use

A

Advanatage of I 125

103
Q

Where is the ligand binding site found in ligand gated ion channels

A

On EC surface at the amino terminal

104
Q

How is the issue of non specific binding overcome

A

Excess of cold ligand, added to second population of test tubes that will displace only selectively bound radioligands.
Comparision between the radiation readings of the displaced selectively bound ligands and the non displaced radioligand will give you the ammount of non selective binding

105
Q

What other factor influences the rate of transport by the Na/K ATPase

A

[ATP]

106
Q

How are some inflammatory mediators involved in the preception of pain

A

Some PGs increase the sensitivity of nociceptors to painful stimuli

107
Q

In what circumstances may rectal administration be favoured

A

In children who cant swallow tablets

In people who can swallow/vomitting

108
Q

What effect do NSAIDs have on BP

A

Increase

109
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Very high specific activities for aromatic hydroxyl groups

A

I 125

Advanatge

110
Q

What are the 7 methods of drug administration

A
Percutaneous 
IV
Intramuscular 
Intrathecal 
Oral 
Rectal 
Inhalation
111
Q

Name the NSAID with a higher selectivity for the COX2 isoorm

A

Diclofenac

112
Q

What are the two main factors which influence drug distribution in the body

A

Binding to plasma proteins e.g. albumin

Partition into specific tissues e.g. body fat, bones and teeth

113
Q

Define efficacy

A

Ability of the drug receptor complex to induce further signalling

114
Q

Define antagonists

A

Drug that prevents the aciton of an agonist

115
Q

If the curve plotted from data collected during a radioligand binding assay doesnt reach a saturation point, what can be inferred

A

Some non-specific binding is occuing

116
Q

What is another word for a primary active transport protein

A

Pump

117
Q

EC [Ca]

A

2x10^-4 mM

20 nM

118
Q

How can we measure pH in large cells

A

Two electodes, one to measure the potential of the entire cell, the othr measures the potential as a result of all ions except H+
This difference between the two values is proportional to the pH

119
Q

How many TM domains does the NHE have

A

12

120
Q

Which receptor family only has a single TM domain and all of its ligans are peptides

A

Kinase linked receptors

121
Q

What are 4 classes of allergen

A

Inhaled mat, injected mat, ingested mat and contacted mat

122
Q

What does NSAID stand for

A

Non sterioidal anti inflammatory drugs

123
Q

VGCC are found on _______________ cells and are activated by ________

A

electrically excitable cells

Depolarisation

124
Q

What does NSAID statnd for

A

Non-sterioidal anti inflamatory drug

125
Q

Give an example of a DMARd and how it works

A

Methotrexate - inhibits the activation of Th1 cells thus preventing inflammation

126
Q

What are the main types of triggers of asthma

A

Atopic (allergies) non-atopic (cold)

127
Q

What causes nausea and stomach pain as a reuslt of NSAID use

A

PGs inhiibit acid sec and protect gut mucosa - less production can lead to ulceration of GI tract

128
Q

[Na]o

A

145 mM

129
Q

What is the efficacy of an invrse agonist

A

Less than 0

130
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

More readily degraded

A

Disad of I 125

131
Q

By what mechanism do kinase-linked receptors work

A

Agonist binding activates the kinase carboxyl terminal or the acitvated receptors recruit and IC kinase

132
Q

What is plotted graphically in a Schild analysis

A

Log (DR-1) against log [antag]

133
Q

What factors does Ec50 depend on

A

Efficacy
Affinity
Number of receptors

134
Q

Is COX2 constit active

A

No is only activated in infalmmatory conditions

135
Q

[Ca]o

A

1 mM

136
Q

How can glucocorticoids be used in the treament of rheu arth

A

Glucocorticoids inhibit the action of TFs that usually promote the transcriptio of pro-inf cytokines

137
Q

T/F

Proteins act to puffer changes in pH which can result in a change of conformation and/or loss of functions

A

T

138
Q

[Ca]i

A

100 nM

139
Q

What are the four main ways drugs are eliminated from the body

A

Exhalation, excretion in the urine, binding to food stuff being excreted in faeces, and presence in sweat and milk

140
Q

EC [K]

A

5 mM

141
Q

What can be said about the DR for an antagonist with a high Kd

A

High Kd means a smaller DR

142
Q

What can be a problem of administering drugs directly to the lungs via inhalation

A

A large proportion of the drug is expired

143
Q

Explain how the _______________ achieves acidifcation

A

Cl/HCO3 exchanger
Inward movement of CL- in exchange for HCO3-
Removal of bicarbonate leaves protons produced by the reaction of water and CO2

144
Q

At rest what can be said about perm of the membrane to Na and K

A

Membrane more permeable to K than Na

145
Q

Act of Th1 cells causes release of which family of inflammatory mediators

A

Cytokines

146
Q

What TM domains of NHE are involved in Na transport

A

4 and 5

147
Q

What is sig about intrathecal drug elimination

A

Intrathecal fat soluble drugs are metabolised poorly - they must conjugate on order to get trapped and be excreted in the urine

148
Q

Composition of lipids in the membrane

A

42%

149
Q

How does the ammout of inhibition change with a irreversible antagonist over time

A

Increases (inhibition) over time

150
Q

Composition of proteins in the cell membrane

A

55%

151
Q

What are the four areas to consider in pharmacokinetics

A

Drug absorption, distribution, metabolism and excretion

152
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Short half life

A

I125 disad

153
Q

Is the resting membrane potential the same in all cells

A

The membrane potential is mainly negative but varies in magnitude

154
Q

IS the exchange of Cl and HCO3- independent of Na

A

YES

155
Q

What are the different types of Ca channels in store membrans

A

IP3 receptors and ryanodine receptors

156
Q

What do occupancy and efficacy span from

A

0 - 1

157
Q

Are more proteins found in the ECF than the ICF

A

Yes

158
Q

A or P COX3 selective

A

Paracetamol

159
Q

What does a high Kd indicate

A

Low affinity

160
Q

Explain how action of aspirin leads to the duration of its effects

A

As aspirin binds permamnetly its duration lasts until all new enzymes have been synthesied usually aorund 4 hours

161
Q

Where does the other 80% contribution of the Vm come from

A

K+ channels - movement of K out of the cell through K channels creating a negative charge inside of the cell and a potential difference between the two sides

162
Q

Well absorbed and metabolised by the liver A or P

A

Paracetamol

163
Q

Composition of carbohydrates in the membrane

A

3%

164
Q

Vm

A

-70 mn

165
Q

What is the function of ROMK in the TAL

A

K+ recycling across the membrane

166
Q

What diuretic will have an inhibitory effect on NHE - what concnetration

A

Low concentration of amiloride

167
Q

What is the name given to the class of small molecules used in rheu arth treatment

A

Disease modifying anti-rehumatic drugs

168
Q

A or P - Weak acid, rapid and efficient absorption

A

Aspirin

169
Q

What three properties determine the effect of a drug in a living system

A

Specificicty, affinity and efficacy

170
Q

How many ions are removed from the cell and how many brought in the the Na/K ATPase

A

3 Na O

2 K I

171
Q

What is the tunrover of active transporters

A

Low turnover

Less than 100 ions per second

172
Q

What is the name of the enzymes inhibited by NSAIDs `

A

Cyclooxygenase enzymes (COX)

173
Q

Are facillitated transport proteins selective

A

Yes - highly

174
Q

Other than the hamberger shift what is another role of AE1 in the red blood cell

A

Long c-terminus links to the cytoskeleton helping to stabilise the membrane

175
Q

How is it possible for EC50 to be lower than the concentration req to occupy 50% of the total receptors (Kd)

A

IC signalling cascades can amplify

Receptor reserve

176
Q

Through which recepotrs do Abs involved in the IR bind and where are they locates

A

IgEs bind to IgE Fc recepotrs on the surface of mast cells found in the skin and mucous membrane

177
Q

Can drugs be 100% specific

A

No drug absolutely specific, high enough concentrations of any drug will cause it to interact with other receptors

178
Q

What does the Na/K ATPase regulate

A

Intracellular ion concentratiosn

179
Q

Explain how the equiptment used in the measuring of pH using floourescence is calibrated

A

Membrane is permeabilised using a protein ionophore and the pH of the bath equated to IC pH

180
Q

Explain how cyclosporine can be used to treat autoimmune diseases

A

Cyclosporine bines to cyclophillin and inhibits calcineurin which prevents the act of NFKB TF and reduces the transcription of pro infl cyto/chemokines

181
Q

Explain how an increase in IC pH can be buffered

A

Dissociation of the carboxyl group on the amino acid is favoured releasing protons

182
Q

What will happen to drugs a low pHs such as the one in the stomach, why is this benificial

A

Dissociation eqbm will shift to the left favouring the reverse reaction leaving more of the drug in its associated deom - this is benificial as more of the drug will be absorbed

183
Q

What is equal at the equillibrium potential

A

Movement of ions due to potential gradient = movement of ions due to concnentration gradient

184
Q

What type of drugs are the majority of clinical useful drugs

A

Antagonists

185
Q

Define competive antaognism

A

Where an antagonist competes with an agonist for occupancy of a receptor

186
Q

Describe the passage of lipid soluble molecules across the membrane

A

Simple diffusion

187
Q

Give examples of lipid-soluble molecules that can cross the endothelial cells and enter the CNS easily

A

Ethanol and caffine

188
Q

What is an issue regarding some of the drug being lost for the oral route of admin

A

Lose some of the drug to to metabolism in the liver/kidney

189
Q

What is the chem name for aspirin

A

Acetylsalicylic acid

190
Q

Which type of transport protein requires either an electrochemical gradeint of a concentration gradient

A

Carrier proteins

191
Q

How are some inflammatory mediators involved in homeostatsis

A

PG A2 - vasodilator
PG D2 - platelet aggregation inhibitor
PG F2 is a bronchoconstrictor

192
Q

When does the Cl/HCO3- become inhibited and when does its rate increase

A

Inhib at a low Ph

Rate increases as it becomes more alkaline

193
Q

What are tissue samples kept at low temps during radioligand binding assays

A

To minimise the activity of hydrolytc enzymes on the cells/receptors

194
Q

When comparing multiple agonists on a conc-resp curve how can more potent agonists be distinguished

A

Conc-resp curve will be shifted to the left

195
Q

What TM domains of NHE are involved in H+ transport

A

6 and 7

196
Q

A or P Reduced risk of Alzheimers

A

Aspirin

197
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Labelling is expensive and difficult

A

Disadvantage 3H

198
Q

Do active transporters work without or against a driving force

A

Yes

199
Q

What type of molecuels is a radioligand binding asay useful for

A

Small molecules

200
Q

Describe the pathogenesis of asthma

A

Trigger –> inf cells to airways -> release inf med such as histamine –> bronchoconstriction

201
Q

What is the major concern with administering some drugs to patients of a high body fat

A

Drugs such as anaesthetics are highly lipid soluble and large ammounts of drug can be trapped in body fat
This means an increased dose of the anaesthetic is required in order to have the desired effect but also means the drug will remain in the body for longer

202
Q

What determines how quickly biologicals injected into muscles enter the blood stream

A

How well perfused the muscle is

203
Q

What is calcineurin

A

A phosphatase found inside T cells that is regulated by Ca

204
Q

How does the reanl exretion of penicillin and diazepan differ

A

Penicillin cleareed in one pass

Diazepan is extremely lipophilic and is thus cleared from the body slowly

205
Q

Is facilitated transport an example of a process which reaches saturation

A

yes

206
Q

How much of the Vm value comes from the action of the NA/K ATPase

A

20%

207
Q

What does the activity of NKCC2 rely on

A

Inward gdt of Na

208
Q

What is the Goldman equation

A

61/z log ((PnaO + PkO)/PNaI + PkI))

209
Q

Why is the movement of NA into cells generally through pathways with physiological significance

A

The ammount of energy required to establish this gradient initially is extremely high

210
Q

What can be said about the Ca gradient

A

1000 fold difference so gradient will favour Ca entry into the cell

211
Q

Is comp antag irreversibel?

A

No reversed by washing

212
Q

What is the most important determinant of the pharmacokinetic characteristics of a drug

A

Lipid solubility

213
Q

Are NSAIDs effective at treating chronic inflmmation

A

No is only activated in infalmmatory conditions

214
Q

What can the Vm vary between

A

-80 – -30mV

215
Q

What is converteed into PGs and thrombx, what is produced from, what enxyme

A

Arachidonic acid - produced from PLS at the membrane by PLA2

216
Q

Define occupancy

A

Total number of receptors occupied at a specific drug concentration over the total number of receptors present

217
Q

T or F People with a predisposition to an allergic phenotype are more likelt to develop allergies

A

Yes

218
Q

What is significant about the B/F against specific binding graph

A

Gradient is -1/Kd

219
Q

What are the four protein targets of drugs

A

Receptors, enzymes, transporters/carriers and ion channel

220
Q

How do pharmacokinetic antagonists work

A

Reduce the ammount of other drugs or alter drug metabolism

221
Q

What does a low Kd indicate

A

High affinity

222
Q

What is meant by electrogenic transport

A

Net movement of charge - charge creating

223
Q

What class of immunoglobins mediates the immune response

A

IgE

224
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Danerous to deal with

A

Disad - 3H

225
Q

Define dose ratio

A

The factor by which agonist conc is required to be increased by in order to elicit the same magnitude of response in the presence of an antagonist

226
Q

What is the strucutre of COX enzymes

A

Made up of two identical subunits wth two active sites

227
Q

What is the name for drugs which only become active once they have been ,etabolised and what is the advantage of this

A

Pro drugs
Slow release of drug and slower induction of effects
e.g. in sedatives and seizure controlling drugs

228
Q

Example of a co-transporter

A

Na/Glucose co transporter

229
Q

What is the equation that allows calculation of the total current carried by a population of ion channels

A

I = N . Po . g . (Vm - Ei)

230
Q

Movements between compartments usually involves penetration of lipid diffusion barriers T or F?

A

T

231
Q

What way do Ca/Na exchangers work in

A

Can work in both directions

232
Q

What can be said about the relative permeabilites of Na and K at rest

A

Membrane is around 50-75x more permeable to K+ than Na+

233
Q

How does excessive paracetamol lead to liver damage

A

Metabolism of paracetamol leads to production of NAPQi - hepatotoxic intermediate that is usually quickly converted but can build up in overdose situations

234
Q

What happens once a drug that is a weak acid gets to the kidneys

A

Basic pH of the Kidneys (~8) will mean that the equillibrium will shift to the right favouring dissociation of the drug. This will prevent it from being reabsorbed due to the negative charge of the undissociated drug preventing it from crossing the cell membrane and therefore causing its excretion in the urine

235
Q

Value of Eca

A

120 mV

236
Q

What can be used in the long term to treat asthma

A

Long actin B2 ags like almeterol delivered with corticosteroids. Glucocorticoid such as beclomastone or antichloinergics like tiotropium brmide that blocks effects of endogenous Ach

237
Q

What is ‘gated pore’ used to describe

A

Channel proteins

238
Q

Which method of drug administration is preferred for biologicals

A

Intramuscular

239
Q

By what two ways could Ca/Na exchanger be electrogenic

A

Ca is a 2+ ion and Na a 1+ ion

Also 3 Na in for every one Ca out

240
Q

What does the Na/K ATPase maintain

A

A low extracellular K concentration

241
Q

How can you create COX2 selective NSAIDS

A

NSAIDs with bulkier groups can only fit into and inhibit the COX2 enxyme due to its wider channel

242
Q

If a partial agonist has the same Ec50 as a full agonist what would happen to its efficacy

A

Efficacy would be lower

243
Q

What can be the negative effect of phase I metabolism of small drugs

A

Can lead to the production of a toxic intermediate e.g. in paracetamol –> NAPQI

244
Q

What is meant by drugs that exhibit zero order kinetics

A

Rate of elimination is constant and does not depend on or vary with the drug intake or plasma concentration of the drug

245
Q

[Na]i

A

15 mM

246
Q

What molecules do NSAIDS prevent synthesis of

A

Protsaglandins and thromboxanes

247
Q

What do antagonists have an efficacy of

A

0

248
Q

Why is COX3 a benificial target for NSAIDs

A

COX3 isnt expressed in the GI tract so its inhibition wont lead to gut irritation and stomach pain

249
Q

What is meant by the term biologicals

A

Peptides which have been engineered to bind with drug-binding proteins

250
Q

What is the most common type of assay used to determine the occupancy/affinity of a drug for its receptor

A

Radioligand binding assay

251
Q

Ena

A

+60 mv

252
Q

Define affinity

A

The ability of a ligand to bind to the receptor

253
Q

Give an example of another drug that is partititoned to a specific tissue

A

Tetracyclin - binds tightly to calcium and so ends up trapped in bone and teeth

254
Q

Give examples of some of the microsomal (IC) enzymes found in the liver that have roles in drug metabolism

A

Cytochrome P450, alcohol dehydrogenase, monoamine oxidase

255
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Easy and cheap in most labs

A

Advantage of I 125

256
Q

IC [Cl]

A

13 mM

257
Q

Approx Ena

A

=61 mV

258
Q

Give an example of a pharmacokinetic antagonist

A

Opiates can reduce absoption of other drugs by biding to gut opiate receptors and reducing gut motility

259
Q

What methods used to separate the unbound radiologand

A

Filtration or centrifugtion

260
Q

Explain how a decrease in IC ph can be buffered

A

Addition of protons to the amino group is favoured removing protons from the system

261
Q

What gene family and superfamily do the Ca/Na exchangers belong to

A

SLC8 gene family

CaCA superfamily

262
Q

What method of drug administration is useful for slow continuous drug administration

A

Percutaneous admin

263
Q

What can be said about buffers with regard to their ability to influence pH

A

Buffers act to minimise the magnitude of a change - but can’t reverse or prvent such change

264
Q

Binding of the Ig to its recepotr occurs after an allergen is detected T or F

A

F - IgE naturaly bound to receptor

265
Q

Drug dose intervals aim to achieve a constant level of the drug, how is this achieved

A

Balancing the rate of excretion with the rate of absoprtion to maintain effective levels

266
Q

What is aspirin and other NSAIDs prescribed for

A

Musculoskeletal pain

267
Q

How can antiobiotics act as pharmacokinetic antagonists

A

Some antibiotics increase the metabolism of drugs like warafarin reducing its effective concentration in the blood stream

268
Q

How is affinity measured

A

Dissociation constant

KD = (K-1) / (K+1)

269
Q

How many TMs of VG CFTR channel

A

12

270
Q

How would you tell the dif bet a drug with a higher Kd when plotted on the same hroup

A

The drug with the highest Kd will have its curve right shifted

271
Q

Why does paracetamol have less side effects than aspirin

A

COX3 not present in the gut thus its inhibition would lead to Gi irritation and stomach pain

272
Q

How does aceylsalicyclic acid prevent PG synth

A

Forms a permanent covalent bond with COX preventing arachidonic acid reaching the cyclooxygenase AS

273
Q

T/F

A high efficacy or affinity of an agonist will shift its concentration-resp curve to the right

A

F - will shift curve left

274
Q

Other than DMARD and calcineurin what other methods are there for treating autoimmune disease

A

Monoclonal ABS which bind to infl mediators such as TNF-A and prevent inflam

275
Q

Which ezymes does asprin show selectively for

A

COX1

276
Q

Example of a GPCR

A

mAchR

277
Q

Explain what the issue is with non specific binding

A

SOme of the radiologand will bind to i.e the test tube and will accouunt for some of the radioactivity reading

278
Q

What is the role Cl/HCO3 exchanger

A

Adds protons into the cell

279
Q

What happens to Na/H exchange at high pH

A

When pH rises above a setpoint NHE becomes inactive

280
Q

A or P A weak anti inflam

A

Paracetamol

281
Q

What can happen to the tight junctions between the capillary endothelium in the brain during inflamation

A

Can become leaky

282
Q

describe mechanism of action for the Na/K ATPase

A

Na IC binds to the channel
Hydrolysis of ATP leads to phosphorylation of the channel and conformational change in the protein
Exposes Na to the EC domain and releases
EC K binds to the channel
Dephosphorylation and conformational change reverting the pump to original confirmation
Exposes K to IC domain - release

283
Q

How can flouresence indicators be used to measure pH in cells

A

Lipid soluble inactive indicator introduced into cells which is then cleaved by naturally occuring IC enzymes. Indicator is then exicted with light of a specific wavelength and the ammount of emitted light of a second wavelength is measured where the ammount of flourescence is proportional to pH

284
Q

In which sex is rheumatoid arthritus more common, how many times

A

3x more common in female

285
Q

When plotted on a semi log graph - conc having a log scale describe the shapes of curved produced in a radioligand binding assay

A

Specific binding shows a sigmoidal curve - reaching point of saturation

Non specific level until very high concentrations where it begins to increase exponentially

286
Q

What structures prevent water soluble molecules from entering the CNS

A

Blood-brain barrier

287
Q

What can be said about the permeability of the mebrane to an ion if the Vm is close to the nernst of that ion

A

Membrane will be permeable

THE CLOSER THE VM IS TO EITHER Ek OR Ena THE MORE PERMEABLE THAT MEMBRANE IS TO THAT ION

288
Q

What happens in phase I of small drug metabolism

A

Modified by enzymes in the liver which carry out catabolic reations

289
Q

What are the units of affinity

A

Molarity

290
Q

Where is COX3 found, what is it and what is it a target of

A

In the CNS, COX1 splice variant, target of paracetamol

291
Q

CaM and PK-C bind to the ____________________________ of NHE to modulate the set point

A

Long intracellular c terminus

292
Q

ADVANTAGE/DISADVANTAGE
H3 OR I(125)

Indisting from native compound

A

Ad H3

293
Q

What three facotrs are involved in controlling IC pH

A

Buffering
Acid extrusion
Acid loading

294
Q

Rough [A-} IC valie

A

-65 mM

295
Q

What are some long term side effects of long term glucocortiocid use

A

Muscle wastage, necrosis of femoral head, inc abd fat, buffalos hump, poor wound healing, tendency to hyperglycamemia, cataracts ect.

296
Q

Come symptoms of rheumatoid arthritus

A

Joint pain, swelling, stiffness and poor sleep

297
Q

The Na/K ATPase is found in all cells but which

A

The red blood cell of the dog - this protein is ubiquitous

298
Q

What is the effect of transporting 3Na in to the cell for every Ca transported out

A

Cubes the Na concentration gradient

299
Q

State the Henderson-Hasselbalch equation

A

Pka = Ph + log (HA/A-)

300
Q

What is the orugh ph of the stomach

A

3

301
Q

Define chemical antagonism

A

Substances that chemically alter agonists resulting in loss of function of the active drug

302
Q

What is seen in first order clearance of a drug

A

Follows a mono-exponential decay model

303
Q

What is meant by an electrogenic transport protein

A

The movement that occurs as a result of the transport proteins results in a net movement of charge

304
Q

What class of enzymes are involved in drug metabolism and of which there are 57 genes for

A

Cytochrome P450 enxymes

305
Q

Which member of the anion exchnger family involved in acid loading

A

Cl/HCO3 exchnager

306
Q

How does the act of mast cells lead to an infla resp

A

Triggers Ca channel opening and iflux, causes degranulation and relase of histamine and tryptase and prod of PGS. Inc Ca –> act of NFkB transcribing pro infl genes

307
Q

T/F

Drugs for a particualr receptor can have the same EC50 but be unable to elicit a maximal response

A

T

308
Q

Which method of drug adminsitration is quickest and used in emergency treatment

A

Intravenous

309
Q

What activates store operated Ca channels

A

Depletion of Ca stores

310
Q

What must drugs cross in order to be metabolised

A

PM

311
Q

How do NSAIDS reduce oedema

A

PGs are vasodilators and so inhibit of PGs leads to decreased vasodilation and a decrease in BP reducing the hydrostatic pressure and fluid efflux from vessels

312
Q

What other methods are used during a radiligand binding assay to preserve the ligand and binding site

A

Intro of protease inhibitors

313
Q

Define pharmacokinetics

A

Study of how drugs are basorbed into the body, how they are distributed and eliminated

314
Q

What are many drugs

A

Weak acids/bases

315
Q

IC [HCO3-]

A

25 mM

316
Q

What two factors determine lipid solubility

A

Partition coefficient and diffusivity diffusion constant

317
Q

State nernst equation

A

61.54 log (ion-out / ion-in)

318
Q

What is the role of the Na/H exchanger

A

Removes protons from the cell

319
Q

Give an example of a kinase-linked receptor

A

Insulin receptor

320
Q

What are the different families of receptor

A

Ligand-gated ion channels, GPCRs, kinase linked receptors and nuclear receptors

321
Q

Mechanically operated Ca channles are found in many cells and respond to

A

Deformation

322
Q

What must be true for drugs given orally

A

They must be resistant to being broken down by the gut

323
Q

What is sig about the x intercept of a schild analysis

A

X-intercept is the affinity of the antagonist

324
Q

Which type of cells mediate the IR in asthma, how is this different to rhu arth

A

Th2 mediate in astham, Th1 in rheu arth

325
Q

Where might the ligand binding site of a GPCR be found

A

On EC surface - for peptides

In pockets created by TM domains

326
Q

Why are certain carriers referred to as secondary active

A

Facilitated transport protein that don’t use ATP hydrolysis for transport but do use the electrochemical gradient set up by ATPases

327
Q

Explain what is meant by enzyme induction and give an example

A

Expression of P450 enzymes for drugs can be influenced by other drugs as well as environmental factors
EG brussel sprouds - induce the expression of enzymes which increase alcohol metabolism

328
Q

What do NSAIDS inhibit

A

Cyclooxygenase enzymes

329
Q

Is the TAL perm to water and NH3

A

No impermeable to both

330
Q

What is the effect of increased agonist concentration in a system which contains an antagonist which is outcompeting the agonist

A

Inc [agonist] - antagonist being out competed and less antagonism

331
Q

What is transport of the Na/K ATPase a saturable function of

A

[Na]i

[K]e

332
Q

T/F - diffusion has a high uptake rate and no saturation point

A

F - it has a low uptake rate and no saturation point

333
Q

What is the chemical name for aspirin

A

Acetylsalicyliic acid

334
Q

Examples of medications taken via inhalation

A

Asthma med

General anasthetics

335
Q

Rough [A-] EC value

A

0 mM

336
Q

What can be used in the short term to treat asthma

A

Salbuatmol B2 ad ag leads to relaxation of the smooth muscle in the airway leading to an inc radius of airway and inc in flow rate

337
Q

Three types of Ca ATPases

A

Plasma membrane calcium pumps - pumps Ca out of the cell
Sarco/endoplasmic calcium pumps - Pump Ca out of the cytoplasm into organelles
Secretory pathway ca pumps - found on the golgi membrane - can also transport Mn2+

338
Q

What does agonist binding reuslt in

A

Stabilising of the receptor conformation that facilitates signalling

339
Q

What happens in phase II of small molecule drug metabolism

A

Enzymes carry out anabolic reactions that involve conjugation to produce an inactive product
Usuaully in large groups - i.e. sugar groups added to prevent absorption and further binding to receptors

340
Q

What is the realationship between Kd and dissociation consant

A

A drug with a high affinity will have a low Kd value

341
Q

What is significant about the drug conc which occupies 50% of the recepotrs

A

Equal to Kd

342
Q

What are the two configurations that can be used in the patch clamp technique

A

Cell attached - record a few ions within a sealed region

Whole-cell - ruptured cell membrane allows recording of all ion channels in cell membrane

343
Q

Example of a nuclear receptor

Examples of a ligand of a nucelar receptor

A

Steroid hormone R

Testosterone
Oestrogen

344
Q

What is meant by the humaisation of Abs before they can be used in humans

A

Mod of Fc domain so AB isnt percieved as foreign by IS

345
Q

pH equation

A

-log [H+]

346
Q

IC [K]

A

100 mM

347
Q

Is affinity a constant

A

Yes

348
Q

The higher the receptor reserve the …

A

Less drug required to cause the maximal response

349
Q

What contributes to airway hyperactivity in asthma

A

Increased backgroud para activity leads to inc in basal tone and inc contraction in response in response to irritants

350
Q

Main side effects of NSAIDS

A

Stomach pain, renal failulre, liver damage, bronchospasm

351
Q

What must be done to the ligand for a radioligand binding assay to be performed

A

Radioactive labelled by tritiation or iodination with I125

352
Q

How many TMDs does a ligand gated ion channel have

A

4

353
Q

How do irreversible antagonists work

A

Form a covalent bond with the receptor

354
Q

Which method of drug adminsitration is is often used for CNS drugs and how is this done

A

Intraethecal injection

Drug into the CSF

355
Q

What type of Ca signalling is found in secretory cells and nerve terminals and is activated by agonit bindning

A

Receptor operated ca channels

356
Q

Which class or drugs can be passively absorbed and why

A

Lipid soluble drugs passively absorbed by moving through the plasma membrane of cells down their concentration gradient

357
Q

A or P Suicide inhibitor

A

Aspirin

358
Q

Explain how aspriirnin is eliminated from the body

A

In phase I the methylester group is replaced by a hydroxyl group converting acetylsalicyclic acid to salicyclic acid
Then in phase II a sugar group is added in a conjugation reaction that produces a glucuronide product

359
Q

What is Na/H exchanger involved in

A

Acid extrusion

NHE removes protons in exhcnage for Na (in)

360
Q

What factors can influence the value of the set point to make the exchanger more active at a higher pH

A

Calcium calmodulin and protein kinase-C

361
Q

How is the resting pH achieved

A

Resting when the rate of acid extrusion equals the rate of acid loading

362
Q

What properties determine the effect of a drug in a living system

A

Efficacy affinity and specificity

363
Q

How is that antibiotics are effective in treating meningitiis despite not being able to cross the BBB in the meninges

A

In patients with meningitis the blood brain barrier becomes leaky allowing for antibiotics to cross over and treat the infection

364
Q

Approx Ek

A

-90mV

365
Q

What factor influences the ammount of time you can spend spearating the unbound ligand

A

Kd - smaller the value the longer needed separating the unbound (as affinity is higher)

366
Q

NAPQI

A

N-acetly-p-benzoquinone-imine

367
Q

What are the main types of transport proteins

A

Carriers, channels and pumps

368
Q

EC [HCO3-]

A

25 mM

369
Q

State the general equation for acid disociation

A

HA –> H+ + A-

370
Q

What is sig about COX1

A

Ubiquitously expressed and constitutively active

371
Q

What domain do nuclear receptors have, what does this achieve

A

DNA binding domain, allows influence of transcription of genes

372
Q

What is meant by the term ligand

A

Generic term for a small molecule or peptide that binds to a receptor and acts as an agonist or antagonist

373
Q

What is seen in patients with asthma

A

Hyperactive airways resulting in bronchoconstriction and decreased radius of the bronchi

374
Q

How is the equiptment used to measure pH in large cells calibrated

A

Electrodes and placed in pH standards and a graph of V against pH is plotted and gdt calculated

375
Q

What are the main issues RE radioligands

A

PURITY - chemically pure, enantiomers filtered out
DEGRADATION - resolved by anti-oxidants and free radical scavenger
LABELLING - high specific activity needed at low tracer concentrations