Neuro phys 2

Question 1

How is electrical flow mediated via electrical synpases?

Answer 1

via connexon channels

Question 2

How is electrical flow mediated via chemical synapses?

Answer 2

via neurotransmitter release

Question 3

What are the steps involved in the synthesis of small-molecule neuro-transmitters?

Answer 3

1. Synthesis of enzymes in the cell body
2. Slow axonal transport of enzymes
3. Synthesis and packaging of neurotransmitter
4. Release and diffusion of neuro-transmitters
5. Transport of precursors into the molecule (from when they were broken down)

Question 4

What are the steps involved in the synthesis of neuropeptide neurotransmitters?

Answer 4

1. Synthesis of neutransmitter precursors and enzymes within the cell body
2. Transport of enzymes and peptide precursors down the microtubule tracts
3. Enzymes modify precursors to produce peptide neurotransmitter
4. Neurotransmitter diffuses away and is degraded by proteolytic enzymes

Question 5

What are ionotropic receptors?

Answer 5

ligand gated ion channels

Question 6

What are metabotropic receptors?

Answer 6

receptor that is coupled to G protein

Question 7

What is the termination of transmission important?

Answer 7

maintains temporal (timing) of signals and prevents receptor desensitisation

Question 8

What are the three main mechanisms for transmitter removal?

Answer 8

Transmitter reuptake
Enzymatic degredation
Diffusion

Question 9

What is the name of the enzyme that is involved in degrading acetyl choline?

Answer 9

acetylcholine esterase

Question 10

What is the name of the enzyme that is involved in the synthesis of acetyl choline?

Answer 10

choline acetyltransferase

Question 11

How many binding sites for acetyl choline are there on a nictonic receptor?

Answer 11

2

Question 12

Name the agonists and antagonists that are involved in both nicotinic and muscarinic receptors:

Answer 12

Nicotinic- nicotinic acid, curare

Muscarinic- muscarine, atropine

Question 13

Where are glutamate receptors commonly found?

Answer 13

50% in the brain

Question 14

What is involved in glutamate synthesis and recycling?

Answer 14

• made primarily from glutamine released by the glial cells
• glutamine taken up by presynaptic terminals via SAT2
• metabolised to glutamate by mitochondrial enzyme glutaminase
• Glutamine is loaded into vesicles by VGLUT
• Recycled through glial cells via EEATS

Question 15

What are the three different types of glutamate receptors and what are they named after?

Answer 15

AMPA (alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate)
NMDA (N-methyl-D-aspartate)
Kainate

(all named after the agonist)

Question 16

What ion do NMDA receptors also allow?

Answer 16

Ca2+

Question 17

What does the NMDA need to be depolarised to function?

Answer 17

when it is not depolarsied Mg2+ ion is not dislodged hence nothing can enter

Question 18

How does long term potentiation occur within the CNS?

Answer 18

at resting potential Mg2+ blocks pathway needs to be depolarised to cause this to exit inducing LTP