Weeks 7-9

Question 1

Electrical transmission

Answer 1

Direct flow of ions from one neurone to another. E.g gap junction

Question 2

What modulates gap junctions?

Answer 2

pH, conc of Ca2+, NTs

Question 3

How many connexins make up a connexon?

Answer 3

6

Question 4

Stages of neurotransmission

Answer 4

1) A.A. NTs synthesised in axon terminal. Peptide NTs formed in soma.
2) NT take up in to vesicles
3) Rise in intracellular [Ca2+] cause NT to be released in to cleft.
4) NT binds on post synaptic membrane.
5) NT broken down/reuptake/diffuses away from synapse.

Question 5

Examples of amine NTs

Answer 5

Dopamine (DA)
NA
Adrenaline
Histamine
5-HT

Question 6

Example of A.A NTs

Answer 6

GABA
Glutamate (Glu)
Glycine (Gly)

Question 7

Examples of peptide NTs

Answer 7

Somatostatin

Substance P

Question 8

Co-existence/Co-transmission

Answer 8

A single neurone that sythesises and releases more than one NT.

Question 9

Synaptic vesicle cycling

Answer 9

Docked vesicle release NT by exocytosis.

Fused vesicle membrane is taken up into the cell by endocytosis.

Question 10

Role of SNARE proteins

Answer 10

Synaptobrevin: vesicle docking

Synaptotagmin: Ca2+ fusion

Question 11

Metabotropic receptors

Answer 11

Coupled to intracellular proteins that transduce signal (slow)

Question 12

Ionotropic receptors

Answer 12

Form ion channels that depolarise or hyperpolarise postsynaptic cell (fast).

Question 13

Temporal summation

Answer 13

Same neuron firing more rapidly

Question 14

Spatial summation

Answer 14

More than one neuron

Question 15

Synaptic potential definition

Answer 15

Difference in voltage between the inside and outside of the post synaptic neurone.

Question 16

Glutamate

Answer 16

Major excitatory NT

Generates EPSP

Question 17

Too much glutamate causes

Answer 17

Excitotoxicity

Question 18

GABA

Answer 18

Generates IPSP by firing Cl-

Question 19

NTs involved in pain

Answer 19

Substance P (peptide) signals pain.

Opioids inhibit substance P release.

Question 20

3 ways signal is terminated

Answer 20

Inactivation of NT
Reuptake of NT
Diffusion away from synapse

Question 21

NMDA receptor

Answer 21

Glutamate and glycine bind here.

NMDA receptors allow the flow of Na+, K+ and Ca2+

Question 22

Structure of metabotropic receptors

Answer 22

7 transmembrane domains

Domains 2,3,6,7 bind NT

G-proteins bind to loop between domains 5 and 6

Question 23

Activation of ion channel via GPCR

Answer 23

1) NT binds to receptor
2) Activates G-protein
3) G protein activates effector protein
4) Effector protein activates 2nd messenger pathway
5) 2nd messenger lead to metabolic changes in postsynaptic cell
6) Opening/closing of ion channel