Chemical substances that function as synaptic transmitters – characteristic of their synthesis, secretion and inactivation

Question 1

synthesis of dopamine

Answer 1

location = substantia nigra + ventral tegmental area

Question 2

secretion of dopamine

Answer 2

AP travels along dopaminergic neurone down axon

voltage gated calcium ion channels open
- influx of ca2+
- fusion of dopamine vesicles with presynaptic membrane

• dopamine released in synaptic cleft travelling via exocytosis
• dopamine binds to post-synaptic membrane receptors = physiological response

Question 3

inactivation of dopamine

Answer 3

reuptaken into pre-synaptic terminal by dopamine transporter proteins

enzymatic degradation in synaptic cleft
- MAO
- COMT

Question 4

dopamine - function 1

Answer 4

nigrostriatal pathway = motor control

Question 5

dopamine - function 2

Answer 5

mesocorticol pathway - cognitive processes like memory/ attention/ problem solving

Question 6

dopamine - function 3

Answer 6

tuberoinfundibular pathway - inhibits prolactin release from anterior pituitary gland for lactation

Question 7

dopamine - function 4

Answer 7

emotional regulation - controls depression/ anxiety/ social behaviour

Question 8

dopamine - function 5

Answer 8

mesolimbic pathway - motivation/ reward pathway

Question 9

dopamine - function 6

Answer 9

circadian rhythm - sleep patten

Question 10

synthesis of GABA

Answer 10

GAD= glutamate decarboxylase

Question 11

secretion of GABA

Answer 11

GABA_A = ionotropic receptors
- ligand receptor channels bind to ligand = conformational changes
= influx of cl- ions inside
- inhibit AP

GABA_B = metabtropic receptors
- g-coupled receptor channels bind to ligand = initiation of intracellular events
= influx of k+ into cells
- inhibit neuronal activity

Question 12

inactivation of GABA

Answer 12

Question 13

GABA - functions

Answer 13

regulation of muscle tone/ sleep/ anxiety/ seizures

Question 14

synthesis of acetylcholine

Answer 14

acetyl CoA + choline —–> acetylcholine + CoA

enzyme = choline acetyltransferse

Question 15

secretion of acetylcholine

Answer 15

AP travels along cholingeric neurone down axon

received by presynaptic membrane causing opening of voltage gated calcium ion channels
- influx of calcium
- causing fusion of ach vesicles onto pre-synaptic membrane

released into synaptic cleft
- travels via exocytosis

reaches post-synaptic membrane
- physiological process

Question 16

inactivation of acetylcholine

Answer 16

reuptaken by choline transporters back to pre-synaptic terminal

enzymatic degradation by AChE in synaptic cleft

Question 17

acetylcholine - function 1

Answer 17

nicotonic acetylcholine receptors = ionotropic
- ligand receptor membrane channels + ligand = conformational changes

influx of na+/ca2+ ions = depolarisation at neuromuscular junction = muscle contraction

Question 18

acetylcholine - function 2

Answer 18

muscarinic acetylcholine receptors = metabotropic
- g-coupled proteins receptor channel + ligand = initiate of intracellular pathways

• found in PNS
• Ach released by preganglionic neurones + postganglionic neurones
• regulation of BP/ digestion/ circulation

Question 19

acetylcholine - function 3

Answer 19

cognition of brain cortex/ hippocampus

• learning
• memory
• decision making

Question 20

acetylcholine - function 4

Answer 20

controls
- sleep-wake cycle
- arousal

Question 21

synthesis of noradrenaline

Answer 21

Question 22

secretion of noradrenaline

Answer 22

AP travels down neurones along axon

detected by presynaptic terminal
voltage gated calcium ion channels
- influx of ca2+
- fusion of noradrenaline vesicle with presynaptic membrane

released into synaptic cleft
- travels along via exocytosis

reaches post synaptic membrane
- physiological process

Question 23

inactivation of noradrenaline

Answer 23

reuptaken by noradrenaline transporter proteins back to pre-synaptic terminal

enzymatic degradation
- MAO
- COMT

Question 24

noradrenaline - function 1

Answer 24

fight or flight response

Question 25

noradrenaline - function 2

Answer 25

mood regulation

Question 26

noradrenaline - function 3

Answer 26

sleep wake cycle

Question 27

synthesis of glutamate

Answer 27

Question 28

secretion of glutamate

Answer 28

AP travels along neurone down axon

detected by presynaptic membrane
- voltage gated calcium ion channels open
- influx of ca2+
- fusion of glutamate vesicles on pre-synaptic membrane

• released by exocytosis onto synaptic cleft
• binds to post-synaptic membrane
  = physiological process

Question 29

inactivation of glutamate

Answer 29

glutamate —-> glutamine
- via glutamine synthase

• reuptaken by EAATs (Excitatory Amino Acid Transporters)
• enzymatic degradation via glutamine synthase

Question 30

glutamate function - 1

Answer 30

NMDA = influx of na+/ca2+ to subside magnesium block

Question 31

glutamate function - 2

Answer 31

AMPA = influx of na+

Question 32

glutamate function - 3

Answer 32

synaptic plasticity

• long term potentation
• long term depression

Question 33

synthesis of serotonin

Answer 33

trytophan ——> 5-hydroxytryptophan (tryptophan hydroxylase) ——-> serotonin (aromatic l-amino decarboxylase)

Question 34

secretion of serotonin

Answer 34

AP travels along neurone down axon

detected by pre-synaptic terminal
voltage gated calcium ion channels open
- influx of calcium
- fusion of serotonin vesiscles

released into synaptic cleft via exocytosis

bind to postsynaptic membrane
= physiological process

Question 35

inactivation of serotonin

Answer 35

reuptaken by serotonin transporters back to pre-synaptic terminal

enzymatic degradation
- MAO

Question 36

serotonin - function 1

Answer 36

5HT1 - mood/ anxiety/ vasoconstriction

Question 37

serotonin - function 2

Answer 37

5HT2 - mood/ cognition/ perception

Question 38

serotonin - function 3

Answer 38

5HT3 - nausea/ vomitting

Question 39

serotonin - function 4

Answer 39

5HT4 - memory/ circadian rhythm