Neurotransmitters in the CNS

Question 1

Characteristics of amino acid neurotransmitters

Answer 1

Possess a NH3 and COOH group

Question 2

Examples of amino acid neurotransmitters

Answer 2

Glutamate, GABA, glycine

Question 3

Is glutamate excitatory or inhibitory?

Answer 3

Excitatory

Question 4

Is GABA inhibitory or excitatory?

Answer 4

Inhibitory

Question 5

Examples of monoamine neurotransmitters

Answer 5

Catecholamines (benzene + 2x hydroxyl groups)

Question 6

Examples of catecholamines

Answer 6

Dopamine, epinephrine, norepinephrine

Question 7

Function of ligand gated ion channels

Answer 7

Moves ions in or out of the cell to make it more positively or negatively charged

Question 8

Function of metabotropic receptors

Answer 8

Activate intracellular signalling cascades and ion channels

Question 9

How is the brain overexcited and how do we stop this?

Answer 9

Too many APs - the direct pathway is overstimulated and indirect is under stimulated
Increases concentration of GABA by preventing formation of glutamate - GABA is inhibitory and prevents excitation
Sodium valproate inhibits sodium channel opening

Question 10

Compare nicotine vs galantamine in the brain

Answer 10

• Galantamine is AChE inhibitor so increases ACh concentration inside cleft, so is excitatory and increases firing and also increases action of ACh on receptors
• Nicotine acts on nAChR so increases firing and is excitatory, requires no presynaptic activity

Question 11

Glutamate effect on postsynaptic membrane

Answer 11

Excitatory

Question 12

How is glutamate cleared?

Answer 12

Glutamine synthase turns glutamate into glutamine which is returned to presynaptic knob by glutamine transporter - diffusion and reuptake

Question 13

Serotonin effect on post-synaptic knob

Answer 13

Both excitatory and inhibitory - acts on GPCR

Question 14

How is serotonin cleared?

Answer 14

Moved out of presynaptic knob by re-uptake and diffusion

Question 15

GABA effect on CNS

Answer 15

Inhibitory via ion channels and GPCR

Question 16

Acetylcholine effect on CNS

Answer 16

Excitatory via ion channels and GPCR

Question 17

How is ACh broken down?

Answer 17

AChE

Question 18

How is dopamine broken down?

Answer 18

Facilitated diffusion into cleft and diffusion to liver where MAO and COMT break down

Question 19

How is ACh made?

Answer 19

Glucose - pyruvic acid - acetyl from pyruvic acid + CoA -> mitochondria - acetyl CoA + choline - acetylcholine
Moved into cleft by exocytosis

Question 20

How is glutamate synthesised?

Answer 20

Glutamine - (mitochondria)-> glutamate -> vesicle -> exocytosis

Question 21

How is glutamate recycled?

Answer 21

glutamate transporter into glial cell

glutamine synthase converts to glutamine

Question 22

How is GABA synthesised?

Answer 22

Glutamine - glutamate - GABA via glutamic acid decarboxylase

Question 23

How is dopamine synthesised?

Answer 23

Tyrosine + L-dopa -> dopamine

Crosses cleft via exocytosis