Neurotransmitters

Question 1

A neurotransmitter should be:

Answer 1

• present in presynaptic terminal
• released in response to stimulation
• able to interact with post-synaptic terminals
• rapidly removed from the synapse

Question 2

What are the 5 steps of transmission?

Answer 2

1) Synthesis
2) Storage
3) Release
4) Post-transmission effects
5) Inactivation

Question 3

What does a neurotransmitter need mechanisms for?

Answer 3

• Synthesis and/or storgae
• Release
• Receptors
• Transmitter removal

Question 4

Size of amino acid and amine neurotransmitters and where are they stored/released?

Answer 4

Small molecules that are stored/released form synaptic vesicles

Question 5

Size of peptide neurotransmitters and where are they stored/released?

Answer 5

Large molecules that are stored in secretory granules

Question 6

What are peptide neurotransmitters stored in?

Answer 6

Secretory granules

Question 7

What do peptide neurotransmitters activate?

Answer 7

Only activate G-protein coupled receptors

Question 8

What are G-protein coupled receptors activated by?

Answer 8

Peptide, amino acid and amine neurotransmitters

Question 9

What is Dale’s principle?

Answer 9

A single neurone has a single neurotransmitter

Question 10

Is Dale’s principle correct? Give a reason

Answer 10

No, many neurones have both types of neurotransmitters

Question 11

Which non-peptides are abundant in all cells?

Answer 11

Glutamate and glycine

Question 12

The synthesis of what is localised to axon terminals by enzymes?

Answer 12

ACh, GABA and amines

Question 13

The synthesis of Each, GABA and amines is localised to where and by what?

Answer 13

Axon terminals and by enzymes

Question 14

What is the most common excitatory transmitter in the CNS?

Answer 14

Glutamate

Question 15

Give examples of receptors that glutamate binds to

Answer 15

NMDA and AMPA

Question 16

What is AMPA important in?

Answer 16

Fast transmission

Question 17

What does the binding of glutamate to AMPA receptors trigger?

Answer 17

Na+ and K+ currents which produces an excitatory post-synaptic potential

Question 18

What do NMDA receptors often co-exist with?

Answer 18

AMPA receptors

Question 19

What kind of block do NMDA receptors have?

Answer 19

A voltage-dependent Mg2+ block

Question 20

Which ion is involved in a voltage-dependent block of NMDA receptors?

Answer 20

Mg2+

Question 21

At resting potential, are NMDA receptors blocked by Mg2+?

Answer 21

Yes, opens as membrane potential increases

Question 22

What does a voltage-dependent block on NMDA receptors mean?

Answer 22

These receptors need to be indirectly activated by another transmitter

Question 23

What is the most common inhibitory transmitter in the brain?

Answer 23

GABA (y-amino butyric acid)

Question 24

Reaction to form GABA

Answer 24

Glutamate ——> GABA + CO2

Requires Glutamic acid decarboxylase

Question 25

Which enzyme is used in the reaction to form GABA from glutamate?

Answer 25

Glutamic acid decarboxylase

Question 26

What does GABA produce via GABA-gated Cl- channels?

Answer 26

ISPS

Question 27

What would happen if there is too much GABA action?

Answer 27

Coma

Question 28

What would happen if there is too little GABA action?

Answer 28

Seizure

Question 29

3 methods of presynaptic inhibition

Answer 29

- One neurone inhibits another - Autoinhibition (neurone inhibits itself) - Disinhibition (neuron inhibits inhibitors)

Question 30

What are anxiolytic drugs? What channels do they act on?

Answer 30

Anxiety-dissolving drugs. Act on GABA-gated Cl- channels

Question 31

What other chemicals can stimulate a response from GABA-gated Cl- receptors?

Answer 31

Ethanol, benzodiazepine, barbiturate, neurosteroid

Question 32

What do PET scans show in patients who suffer from panic attacks?

Answer 32

Loss of GABA A receptors

Question 33

What are GABA A receptors?

Answer 33

GABA-gated Cl- channels

Question 34

What system do opiates act in?

Answer 34

The endogenous opiate system

Question 35

Which was discovered first: opiate antagonists or endogenous opiates? Give the name of which one

Answer 35

Opiate antagonist: Naloxone

Question 36

How are opiates synthesised?

Answer 36

Formed in rough ER and packaged into secretory granules

Question 37

What are the 3 main types of opiate receptors?

Answer 37

µ (mu), κ (kappa), σ (sigma)

Question 38

Give examples of where many opiate receptors are found

Answer 38

- Spinal cord - Periaqueductal grey - Amygdal - Frontal cortex - Brain stem

Question 39

Opiate receptors are coupled with what?

Answer 39

G-protein

Question 40

What are the downsides of using opiates for therapeutic purposes?

Answer 40

Tolerance and dependence develops

Question 41

What are some therapeutic uses of opiates?

Answer 41

Analgesia Intestinal disroders Antitussive

Question 42

What is analgesia?

Answer 42

Reduction in the perception of and emotional response to pain

Question 43

What are antitussives?

Answer 43

Cough suppressants

Question 44

Where is most of the body's serotonin produced?

Answer 44

In the GI tract