NT of the brain

Question 1

GABA

Answer 1

main INHBITORY NT in the brain (trace amounts in other tissue)

Question 2

Glycine

Answer 2

main INHIBTORY NT in the brainstem and spinal cord

Question 3

Glutmate

Answer 3

main EXCITATORY NT in the body

Question 4

two types of GABA which different receptors

Answer 4

GABAa

GABAb

Question 5

GABAa receptor

Answer 5

ligand gated chloride channels- hyperpolarization- reduces excitability

• allowing influx of cl- ins- taking the neurone further from its threshold potential

Question 6

GABAb

Answer 6

signals via Gi/Go

- inhibiting VOCCs and opens K+ channels= reducing excitability

Question 7

GABA is synthesised from

Answer 7

glutamate

Question 8

GABAergic neurones represent the sole output of the

Answer 8

cerebellar codex and plays a major role in basal ganglia pathways

Question 9

glycine have a similar mode of action to

Answer 9

GABAa

- opening ligand gated chloride channels- hyperpolarization

Question 10

both GABA and glycine are

Answer 10

used by many interneurones including those involved in regulation of muscle tone

Question 11

describe Gi/Go

Answer 11

1) ligand binds and beta/gamma complex dissociates
2) Gi protein inhibits adnelyl cycle
3) less cAMP produced
4) less pKA
Go part
1) excited GIRKs (gated INWARDLY rectifying potassium ) channel
2) causing influx of K+
3) hyperpolarisation

Question 12

Two types of receptors for glutamate

Answer 12

Ionotropic- ligand gated cations

Metabotropic- mGlu

Question 13

Glutamate inotropic receptors

Answer 13

NMDA
AMPA
Kainate

Question 14

NMDA glutamate receptors

Answer 14

calcium

- Magnesium block, therefore certain level of depolarisation needed

Question 15

AMPA and kainate glutamate receptors

Answer 15

Na+

Question 16

Metabotropic glutamte receptors

Answer 16

metabotropicGlu GPCR

- signal via Gaq

Question 17

mGlu and Gaq

Answer 17

1) glutamate binds
2) causes gabba/beta to dislocate from Gq
3) triggers PLC to hydrolyse IP3 to PIP2 and DAG
4) DAG- PKC
5) IP3- SR calcium release

Question 18

Glutamate and NMDA

Answer 18

NMDA has large proc so will allow larger cations through- has Mg2+ bock, will only be removed at certain potential

Question 19

Glutamate and AMPA and kainate

Answer 19

smaller pores so will only let Na thoguh- FAST

Question 20

catecholamines include

Answer 20

adrenaline
noradrenaline
dopamine

Question 21

what is the main precursor of catecholamines

Answer 21

tyrosine kinase

Question 22

where are noradrenaline and adrenal released from

Answer 22

adrenal medulla

Question 23

pathway of making catecholamines

Answer 23

1) phenylalanine - essential AA
2) tyrosine
3) DOPA
4) dopamine
5) noradrenaline
6) adrenaline

Question 24

dopamine

Answer 24

released in the brain to coordinate movement

• corpus striatum
• precursor is L-DOPA

Question 25

which enzyme converts L-DOPA

Answer 25

DOPAdecarboxylase

Question 26

Noradrenlaine

Answer 26

mostly release in the brainstem
-locus coerulues
0 mainly found in the brain where adrenergic neurones are found
-involved in behaviour arousal for threat or unfamiliar situations

Question 27

noradrenaline is stimulatory for

Answer 27

heart regulation (B1)
vasodilation in the lungs (B2)

Question 28

dopaminergic synapse

Answer 28

1) tyrosine diffuses into neurone
2) converted to DOPA
3) converted to Dopamine and stored in synaptic vesicle
4) impulse cause calcium to flood in and causes SNARE proteins to transport the vesicles the synapse
5) release int cleft and stimulate D1R and D2R
6) dopamine is recycled back tot he presynaptic membrane by dopamine transporter
7) converted to DOPAC by MAO

Question 29

adrenaline

Answer 29

Also known as epinephrine
Hormone, NT and medication
Produced by adrenal glands and certain neurones
Play an imporntant role in fight or flight repsosne by increasing blood flow to muscle, output of the hear, pupil dilation and blood sugar
Does this by binding to alpha and beta receptors

Question 30

serotonin

Answer 30

5-HT

• monamine NT
• contirbutor to feelings of well-being and happiness
• treamtent for depression

Question 31

serotonin strongly influences

Answer 31

the transmission of other NT, including dopamine and noradrenaline- reciprocal relationship

Question 32

D1R

Answer 32

direct- stimulatory

Question 33

D2R

Answer 33

indirect- inhibitory

Question 34

two pathways of Dopamine which control movement

Answer 34

• direct- stimulates cortex for movement

- indirect- inhibits context to stop movement

Question 35

Direct dopaminergic pathway

Answer 35

inhibitory neurone connecting the basal ganglia and thalamus are inactivated- therefore the thalamus can send excitatory input to motor cortex and movement can occur

Question 36

Indirect dopaminergic pathway

Answer 36

inhibiting neurones are activated. so movement is prevented

Question 37

why is the indirect pathway important

Answer 37

• allows us to stay at rest

- when we want to move the indirect pathway is tuned off and the direct pathway is turned on

Question 38

dopamine related forms the substantial nigra cells will

Answer 38

both activate and inactivate direct pathway

Question 39

Direct pathway detail

Answer 39

1. Cortex provides excitatory input to the striatum
2. The striatum then puts an inhibitory output to the GPI and SNR
3. Therefore inhibition the inhibitory neurones leading to the to the thalamus
4. This means the thalamus can send excitatory input to the cortex

Overall effect is to stimulate the cortex

Question 40

indirect pathways

Answer 40

1. Cortex provides excitatory input to the striatum
2. However, striatum then provides inhibitory input to the GPE
3. GPE, therefore sends inhibitory input to SNP- inhibits the thalamus
4. Preventing the thalamus from sending excitatory input to the cortex

Longer and less direct.