Chemical signalling

Question 1

what are the two main amino acid neurotransmitters?

Answer 1

glutamate and GABA

Question 2

where do glutamate and GABA act?

Answer 2

CNS (brain and spinal cord)

Question 3

describe the process of glutamate synthesis and storage and reuptake

Answer 3

1. synthesized from glutamine
2. loaded and stored in vesicles by vesicular glutamate transporters
3. removed from synapse by excitatory amino acid transporters

Question 4

what is glutamate excitotoxicity?

Answer 4

when there is too much glutamate stimulation (not removed from synapse) - damages neurons

Question 5

what are agonists and antagonists?

Answer 5

agonist - a drug that binds with receptor and produces a reaction
antagonist - a drug that binds with a receptor that reduces or blocks the reaction

Question 6

what is kinetics?

Answer 6

the rate of transmitter binding and channel gating determines the duration of effects

Question 7

what are the 2 main glutamate ionotropic receptors?

Answer 7

NMDA and AMPA receptors

Question 8

describe the NMDA receptor

Answer 8

• glutamate ionotropic receptor
• for calcium channel to open, glutamate and glycine must both bind
• APV blocks glutamate from binding (antagonist)

Question 9

describe AMPA receptor

Answer 9

• glutamate ionotropic receptor

- controls opening of sodium channels

Question 10

describe the process of GABA synthesis and storage and reuptake

Answer 10

1. synthesized from glutamate
2. loaded and stored into vesicles by GABA transporter
3. removed from synapse by GABA transporters

Question 11

what happens when there is too much GABA?

Answer 11

sedation or a coma

Question 12

describe GABA A receptors

Answer 12

• GABA ionotropic receptors
• controls chloride channels
• muscimol = agonist
• bicuculine = antagonist

Question 13

what are drugs that reduce GABA activity called? give some examples

Answer 13

anxiolytic e.g benzodiazepines, barbituates

Question 14

what is neuromodulation?

Answer 14

affecting the response properties of a neuron, but don’t carry primary information themselves. e.g dopamine, serotonin

Question 15

where are the dopamine neurons located?

Answer 15

in the midbrain: ventral tegmenta area (VTA) & substantia nigra (SN)

Question 16

what does the nigrostriatal system play a role in?

Answer 16

movement

Question 17

what system plays a role in reinforcement?

Answer 17

mesolimbic system

Question 18

what does the mesocortical system play a role in?

Answer 18

functions such as working memory and planning

Question 19

describe the process of dopamine synthesis

Answer 19

1. Dopamine is synthesised from tyrosine by tyrosine hydroxylase(TH)
2. this becomes L-Dopa, which becomes dopamine when catalyzed by DOPA decarboxylase

Question 20

what group of neurotransmitters is dopamine part of?

Answer 20

monoamines

Question 21

what drug prevents storage of monoamines?

Answer 21

reserpine

Question 22

describe the process of serotonin synthesis

Answer 22

1. made from tryptophan by tryptophan hydroxylase
2. this produces 5-HTP
3. this produces serotonin when catalyxed by 5-HTP decarbyoxylase

Question 23

what is fluoxetine?

Answer 23

a drug that blocks serotonin reuptake (anti-depressant)

Question 24

describe the cholinergic system

Answer 24

• primarily acts in the PNS

- uses the neurotransmitter Acetylcholine

Question 25

describe acetylcholine synthesis, storage and release

Answer 25

1. made from choline 2. stored in vesicles 3. calcium dependent exocytosis

Question 26

what drug blocks the breakdown of ACh?

Answer 26

acetylcholinesterase inhibitors

Question 27

what drug prevents the release of ACh?

Answer 27

botulinum toxin (botox)