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Flashcards in Neuropharmacology Deck (145)
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1
Q

What is a neurotransmitter?

A

released by presynaptic terminals and produce rapid excitatory or inhibitory responses in postsynaptic neurons

2
Q

Give examples of fast neurotransmitters?

A

glutamate; GABA

3
Q

What type of channel do fast neurotransmitters operate through?

A

ligan-gated ion channels

4
Q

What are neuromodulators?

A

released by neurons and by astrocytes, produce slower pre- or post-synaptic responses, indirectly modulate the probability of other ion channels opening in response to voltage changes

5
Q

What are neurotrophic factors?

A

released mainly by non-neuronal cells and act on tyrosine kinase-linked receptors that regulate gene expression and control neuronal growth and phenotypic characteristics

6
Q

How do slow neurotransmitters and neuromodulators work?

A

through GPCRs

7
Q

Give examples of agents which work as both neurotransmitter and modulator, using both ion channels and GPCRs?

A

glutamate; 5-HT; ACh

8
Q

What is a psychotropic drug?

A

drug that affects mood and behaviour

9
Q

What is the principal excitatory transmitter in the CNS?

A

L-glutamate

10
Q

What is the action of memantine?

A

NMDA-antagonist

11
Q

How is glutatmate in the CNS synthesised?

A

mainly from glucose via Kreb cycle or glutamine synthesised by glial cells

12
Q

What are hte main inhibitory amino acids?

A

GABA; glycine

13
Q

How are fast neurotransmitters stored?

A

synaptic vesicles

14
Q

How are neurotransmitters released from synaptic vesicles?

A

calcium dependent exocytosis

15
Q

What happens glutamate taken up by astrocytes

?

A

converted to glutamine

16
Q

Give an example of an ionotrophic receptor?

A

ligand-gated ion channel

17
Q

Give an example of a metabotrophic receptor?

A

GPCR

18
Q

What are the 3 types of glutamate receptor?

A

NMDA; AMPA and kainate

19
Q

How many types of subunit are NMDA receptors made from?

A

7

20
Q

What is the function of the dendrites of a neurone?

A

receive inputs from other neurones and convey graded electrical signals passively to the soma

21
Q

Where is the site of initiation of the AP in the neurone?

A

axon hillock and initial segment

22
Q

Give an example of a unipolar neurone?

A

peripheral autonomic neurone

23
Q

Give an example of a pseudounipolar neurone?

A

dorsal root ganglion neurone

24
Q

Give an example of a bipolar neurone?

A

retinal bipolar neurone

25
Q

Give an example of a multipolar neurone?

A

lower motor neurone

26
Q

What are the 4 functional regions of neurones?

A

input; integrative; conductile; output

27
Q

What defines the distance over which a current spreads thorugh the axon?

A

membrane resistance and axial resistance of the axoplasm

28
Q

What is the most common type of synapse?

A

axodendritic

29
Q

What is the least common type of synapse?

A

axoaxonic

30
Q

Where do vesciles containing neurotransmitter cluster presynaptically?

A

around the active zones

31
Q

Where are the neurotransmitter receptors found in greatest numbers postsynpatically?

A

postsynaptic density

32
Q

What effect does glutatmate release have on the post-synaptic terminal?

A

causes influx of sodium, resulting in an epsp

33
Q

What effect does GABA have on the postsynaptic cleft?

A

chloride release and an ipsp

34
Q

What is the difference between spatial and temporal summation in synaptic integration?

A

spatial: many inputs determine the output whereas temporal- AP frequency of one single input determines outpu

35
Q

What are peptides released from?

A

secretory vesicles

36
Q

Why is the synthesis of glycine and glutatmate different to GABA and amines?

A

glycine and glutamate are amino acids foudn in every cell whereas GABA and amines aren’t

37
Q

What type of receptor is GABAa?

A

ligand-gated ion channel

38
Q

What type of receptor is GABAb?

A

GPCR

39
Q

Where are GABAa receptors mainly located in the synapse?

A

post-synpatically

40
Q

How do GABAb receptors work?

A

inhibit voltage gated Ca channels to reduce trasmitter release and increase potassium conductance both pre- and post synaptically

41
Q

How do GABAa receptors work?

A

allow chloride into neurone, hyperpolarising it

42
Q

What is long term potentiation?

A

prolonged enhancement of synaptic transmission that occurs at various CNS synapses following a short burst of high-freq presynaptic stiulation

43
Q

What does activation of NMDA receptors require?

A

binding of both glutamate and glycine

44
Q

What is the general structure of ionotropic glutamate receptors?

A

tetramer

45
Q

What is the general difference between NMDA and AMPA receptors in terms of effector mechanism?

A

NMDA: slow kinetcs with high Ca permeability whereas AMPA have fast kinetics with low Ca permeability

46
Q

What ion blocks NMDA receptors?

A

Mg

47
Q

How do BZDs act on GABA receptors?

A

bind to an accessory site (BZD receptor) on GABAa

48
Q

What receptor does baclofen work on?

A

GABAb

49
Q

Where is glycine found in particularly high concentrations?

A

spinal cord

50
Q

What neurotransmitter is affected by tetanus toxin?

A

prevents glycine release at inhibitory interneurons resulting in excess reflex hyperexcitability and spasms

51
Q

How is GABA made?

A

from glutamate by glutaminc acid decarboxylase

52
Q

What are the principal amine transmitters?

A

5-HT; ACh; dopamine

53
Q

Where is the most prominent cluster of NA cell bodies?

A

locus coeruleus in the pons

54
Q

What type of receptor are adrenoceptors?

A

GPCR

55
Q

What are the functions of noradrenergic transmission?

A

arousal system; blood pressure regulation and control of mood

56
Q

Give examples of drugs which act of noradrenergic transmission in the CNS?

A

antidepressants; cocaine; amphetamine

57
Q

Where is dopamine foudn in the highest quantities in the brain?

A

corpus striatum

58
Q

What are the 4 main dopamine pathways in the brain?

A

1- nigrostriatal pathway
2-mesolimbic pathway
3-mesocortical pathway
4- tuberohypophyseal

59
Q

What is theanatomy nigrostriatal pathway?

A

cell bodes in the substantia nigra with axons terminating in the corpus striatum

60
Q

Where are the cell bodies for the medolimbic pathwya?

A

midbrain ventral tegmental area

61
Q

Where do neurones from the ventral tegmental area project to?

A

nucleus accumbens and amygala

62
Q

What is the anatomy of hte mesocortical pathway?

A

cell bodies in the ventral tegmental area projecting to the frontal cortex

63
Q

What is the tuberhypophyseal pathway?

A

hypothalamus to pituitary

64
Q

What are the two families of dopamine receptors?

A

D1 and D2

65
Q

Which receptors does D1 family include?

A

D1 and D5

66
Q

Which receptors does D2 family include?

A

D2,D3 and D4

67
Q

Which dopamine receptors are most abundant?

A

D1

68
Q

Where are D1 receptors found?

A

areas receiving dopamine innervation e.g striatum; limbic system; thalamus and hypothalamus

69
Q

Where are D2 receptors found?

A

same as D1 plus pituitary gland; act as inhibitory auto-regulators

70
Q

Where are D3 receptors found?

A

limbic system but not striatum

71
Q

What receptor is dopamine action in the periphery mediated by?

A

D1

72
Q

What type of dopamine receptor in found in the vomiting centre?

A

D2

73
Q

What other neurotransmitter does dopamine act as a precursor for?

A

NA

74
Q

What is the general function of the nigrostriatal pathway?

A

motor control

75
Q

What is the general function of dopamine in the mesolimbic pathway

A

emotion and drug-indicued reward

76
Q

Waht is the general function of the mesocortical pathway?

A

emotion

77
Q

What type of GPCR are D1 type receptors linked to?

A

Gs

78
Q

What does Gs activation cause?

A

activation of adenylyl cyclase

79
Q

What type of GPCR are D2 type receptors linked to?

A

Gi/G0

80
Q

What does Gi/G0 activation cause?

A

inhibits adenylyl cyclase; activates K channels, inhibits Ca channels and may activate phospholipase C

81
Q

What is the relationship of D1 and D2 type receptors to SZ?

A

D1: negative symptoms; D2: positive symptoms

82
Q

What is the degredation product of serotonin that is excreted in hte urine?

A

5-HIAA

83
Q

What are the raphe nuclei?

A

cell bodies of 5-HT which are grouped in the pons and upper medulla close to midline (raphe)

84
Q

What type of receptor are serotonin receptors?

A

GPCR except for 5-HT3 which is ion channel

85
Q

Give an example of a 5-HT1D receptor agonist?

A

sumatriptan

86
Q

Give an example of a 5-Ht3 receptor antagonist?

A

ondansteron

87
Q

What are the Gq coupled ACh receptors?

A

M1,M3 and M5

88
Q

What are the Gi/Go coupled ACh receptors?

A

M2 and M4

89
Q

What is the action of Gq coupled ACh receptors?

A

excitation thorugh blockade of M-type K channels

90
Q

What is the action of Gi/Go coupled ACh receptors?

A

inibitory thorugh activation of potassium channels and block Ca channels

91
Q

Where are nicotinic ACh receptors found usually in the CNS?

A

presynaptically

92
Q

What is the funciton of nACHRs

A

usually to facilitate the release of other transmitters

93
Q

Which type of ACH receptor (muscarinic or nicotinic) is more important in CNS function?

A

muscarinin

94
Q

What function do nACHRs mediate that mACHRs dont?

A

behavioural arousal

95
Q

What type of histamine receptor antagonist are anti-emetic?

A

H1

96
Q

What is the general function of adenosine?

A

inhibitory (caffeine is an antagonist of A2 receptors and increases wakefulness)

97
Q

What is misfolding?

A

abnormal conformations of proteins such that they tend to form large insoluble aggregates

98
Q

How does glutatmate cause excitotoxicity?

A

activates NMDA; AMPA and metabotropic receptors. Activation of AMPA depolarises the cell; unblocks NMDA receptors, permitting Ca entry. and opens Ca receptors, releasing more glutamate. metabotropic receptors cause release of intracellular Ca. Na entry causes more Ca entry. Depolarisation inhibits glutamate uptake- lots of glutamate in extracelllular space

99
Q

What ion is central to excititotoxicity?

A

calcium

100
Q

What are the functions of raised calcium?

A

increased glutamate release; activation of proteases and lipases which damage the membrane; activation of nitric oxide; increased arachidonic acid release

101
Q

What type of glutamate receptor is excitotoxicity mainly associated with?

A

NMDA

102
Q

What is found extracellularly in Alzhemiers?

A

amyloid plaques

103
Q

What is found within the neurones in Alzhemiers?

A

neurofibrillary tangles

104
Q

What are the amyloid plaques in Alzhemiers made of?

A

beta-amyloid protein

105
Q

What are the neurofibrillary tangles made of?

A

filaments of phosphorylated form of microtubule associated protein- Tau

106
Q

What is the precursor of amyloid protein?

A

amyloid precursor protein

107
Q

Which chromosome is amyloid precursor protein found on?

A

21

108
Q

What is the characteristic transmitter system loss in AD?

A

loss of cholinergic neurons in the basal forebrain nuclei

109
Q

Where do the mutations involved in familial AD lie?

A

in APP gene or presenillin gene (both increase beta-amyloid protein

110
Q

What condition is amantadine used to treat?

A

Parkinsons

111
Q

What is the action of amantadine?

A

act by releasing dopamine

112
Q

What are the slowly-developing side effects of levodopa?

A

dyskinesia (within 2 years of therapy); rapid fluctuations in clinical state

113
Q

What is the action of domperidone?

A

dopamine antagonist in the chemoreceptor trigger zone but doesnt access basal ganglia

114
Q

What other drug is given with levodopa and why?

A

inhibitor of peripheral dopa decarboxylase e.g carbidopa to reduce SE

115
Q

What amino acid is huntingtin composed of?

A

glutamine

116
Q

What is thought to be the cause of hyperactivity of dopaminergic synapses?

A

loss of GABA-mediated inhibition of the basal ganglia

117
Q

What is use-dependence, a feature of anti-epileptic drugs?

A

block preferentially the excitation of cells that are firing repetiively, and have higher block with higher frequency

118
Q

How does use-dependence arise?

A

preferential binding to channels in inactivated state ( just after depolarisation)

119
Q

What channel is thought to be invovled in absence seziures?

A

calcium channels

120
Q

What is antipyschotic potency realted to?

A

activity on D2 receptors

121
Q

What is the activity of tricyclic antidepressants?

A

block noradrenaline and 5-HT reuptake

122
Q

What controls the discharge of hypothalamic cells?

A

noradrenergic and 5-HT inputs

123
Q

What type of seizure are sodium channel blockers used in

A

partial and secondarily general seizures

124
Q

What are T-type calcium channels?

A

normally depolaried and inactive in the awake state

125
Q

What seizure are T type Ca channels implicated in?

A

absence seizures

126
Q

What is the function of voltage operated caclium channels?

A

control caclium entry into neuronal terminals and regulate neurotransmitter release

127
Q

What is the common side effect to sodium channel inhibitors?

A

SJS

128
Q

What are the side effects of lamotrigine?

A

sleep disturbances, hallucinations and occasioanl increases in seaizure frequeny

129
Q

What is the kinetics of phenytoin?

A

zero-order

130
Q

What is the mechanism of carbamazepine?

A

Na channel inactivation

131
Q

What is the actions of valproate?

A

sodium; T-Ca channels inactivation/ block and GABA channel activation

132
Q

What are the actions of lamotrigine?

A

Na channel and voltage Ca channel block

133
Q

What is the action of phenytoin?

A

sodium channel inavtication

134
Q

What are the actions of gabapentin?

A

voltage Ca channel block and glutamate channel inhibition

135
Q

What is the step that results in GPCR inactivation?

A

GTP hydrolysis

136
Q

What is the action of Gs receptors?

A

activate adenylyl cyclase

137
Q

what is the action of Gq receptors?

A

stimulates phospholipase C

138
Q

What is the action of Gi receptors?

A

inhibits adenylyl cyclase

139
Q

What is the function of adenylyl cyclase?

A

catalyses formation of cAMP

140
Q

What is the major effect of cAMP?

A

to activate protein kinase A

141
Q

How is cAMP broken down?

A

phosphodiesterase

142
Q

What is the action of phospholipase C?

A

cuts PIP2 to generate IP3 and DAG

143
Q

What is the function of IP3?

A

opens ligand gated Ca channels on the endoplasmic /sarcoplasmic reticulum

144
Q

What is the function of DAG?

A

activates protein kinase C

145
Q

What binds to GPCRs in desensitisation?

A

beta-arrestin