Lecture 3

Question 1

What is the purkinje cell?

Answer 1

main cell of the cerebellum and is inhibitory

Question 2

What are pyramidal cells?

Answer 2

Main cell in cortex, excitatory

Question 3

What is the language of neurones?

Answer 3

Action potentials- electrical signal, neurotransmission is the chemicals signal

Question 4

What determines whether a neurone is excitatory or inhibitory?

Answer 4

The type of neurotransmitter it releases

Question 5

Describe the process of neurotransmitter release

Answer 5

Neurone is depolarised which causes calcium to enter via voltage gated calcium channels which causes vesicles containing neurotransmitter to exocytosis the neurotransmitters into the synaptic cleft

Question 6

Which post synaptic membrane is thicker?

Answer 6

The excitatory synapse- the post synaptic density

Question 7

What is the criteria to be a neurotransmitter?

Answer 7

In neurones, release is calcium dependent and occurs from depolarisation, specific receptor is on post-synaptic side, mechanisms of removal, reuptake and breakdown must be present.

Question 8

What are the three types of neurotransmitter?

Answer 8

Low MW, neuropeptides, gases

Question 9

What are some types of low MW neurotransmitters?

Answer 9

Ach, Amino acids, purines, amines

Question 10

Which amino acids are excitatory?

Answer 10

Glutamate and aspartate

Question 11

Which amino acids are inhibitory?

Answer 11

Glycine and GABA

Question 12

Where is GABA to major inhibitory NT?

Answer 12

The brain

Question 13

Where is glycine the major inhibitory NT?

Answer 13

The spinal cord

Question 14

What are some examples of amine NT?

Answer 14

Adrenaline, Noradrenaline, histamine, dopamine, serotonin

Question 15

What are some examples of neuropeptide NT?

Answer 15

Substance P, neuropeptide-Y

Question 16

Where does co-transmission of glutamate and GABA occur?

Answer 16

In specialised cells of the dorsal horn of spinal cord.

Question 17

What type of NT are held in the dense-core vesicles?

Answer 17

Larger neuropeptides

Question 18

What NT are held in the small clear vesicles?

Answer 18

Low MW NT

Question 19

What is the process of synthesis of low MW NT?

Answer 19

Enzymes are synthesised in the soma then transported down the axon via kinesin/microtubules. Enzymes synthesise the NT from precursors in the terminal then package into vesicles

Question 20

What is the process of synthesis of neuropeptides?

Answer 20

Synthesised and packaged into vesicles in the soma then transported to terminal.

Question 21

What are the two types of vesicles?

Answer 21

Small clear vesicles (low MW NT) and dense-core vesicles (neuropeptides).

Question 22

Describe the process of release of NT

Answer 22

depolarisation causes calcium influx which causes the vesicles to dock close to the membrane and release contents into the synaptic cleft

Question 23

How does recycling differ for Low MW and neuropeptides?

Answer 23

Low MW NTs are recycled via being actively taken up by neurones or glial cells. Neuropeptides are not recycled, they are extracellularly degraded by proteases

Question 24

What are the two types of receptor?

Answer 24

Ionotropic and metabotropic

Question 25

What are ionotropic receptors?

Answer 25

Ion channels. Binding of NT causes conformational change so pore opens. 1:1 ratio

Question 26

Describe metabotropic receptors

Answer 26

Transmembrane proteins which when NT binds, they activate a G protein, alpha subunit has stimulatory or inhibitory effect on the effector protein which then can open or close a channel. slower process but has amplification via second messengers.

Question 27

Describe the processes of removal from the synaptic cleft

Answer 27

Low MW NT typically diffuse and are reuptaken into nerve terminals or glial cells. Neuropeptides are broken down by extracellular proteases.

Question 28

What are autoreceptors?

Answer 28

Present on presynaptic membrane and prevent the further release of NT.