Synaptic Transmission

Question 0

Divergence

Answer 0

Neurone provides synaptic input to many other neurones

Question 1

Convergence

Answer 1

Neurone has synaptic input from a variety of other neurones

Question 2

What determines if a synapse is inhibitory or excitatory?

Answer 2

The contents of the synaptic vesicles which bridge the synaptic cleft

Question 3

Define Spacial Summation

Answer 3

When many neurones exert the same effect on a post synaptic membrane, producing a much larger response

Question 4

Define Temporal Summation

Answer 4

When several APs arrive in succession to have a greater effect than 1 AP alone

Question 5

What does NT cause at the post synaptic potential in an ipsp?

Answer 5

Hyperpolarisation

Question 6

What does NT cause at the post synaptic membrane in an epsp?

Answer 6

Depolarisation

Question 7

Name the 3 classes of NTs

Answer 7

Amino acids
Amines & Purines
Peptides

Question 8

Give examples of type 1 NTs (amino acids)

Answer 8

Glutamine
GABA
Glycine

Question 9

Give examples of type 2 NTs (amines & purines)

Answer 9

ATP
Adenosine
ACh
Dopamine
NA
Serotonin

Question 10

Give examples if type 3 NTs (peptides)

Answer 10

Cholecystokinin
Metenkephalin
Substance P
Vasopressin

Question 11

List in order the concentrations of type 1,2 & 3 NTs in the CNS

Answer 11

Type 1= relatively high conc
Type 2= slightly lower conc
Type 3= very low conc

Question 12

Which is faster- ionotropic or metabotropic receptors?

Answer 12

I= fast, rec usually directly linked ion channels, open when NT binds.

M= slower, rec coupled effector ion channel (via G protein or 2nd messenger)

Question 13

What are the major excitatory receptors if the CNS?

Answer 13

Glutamate receptors

Question 14

What results from excessive activity if glutamate receptor?

Answer 14

Over active neurones
Seizures
Cell death

Question 15

Why does excessive glutamate rec activity produce these effects?

Answer 15

Rec allow Ca entry= neurotoxicity at high levels

Question 16

Name the 3 major types of glutamate receptor

Answer 16

NMDA
Non-NMDA-fast depolarising
Metabotropic

Question 17

What type of receptor is the NMDA glutamate rec?

Answer 17

Ionotropic

Question 18

What ions do the NMDA glutamate rec allow through?

What does this lead to?

Answer 18

Na+
Ca2+

Fast depolarisations

Question 19

Name the ion non-NMDA-fast depolarising receptors are permeable to.

Name it’s agonist.

Answer 19

Na+

AMPA/ Kainite

Question 20

What are the metabotropic glutamate receptors linked to?

Answer 20

G proteins & 2nd messenger couplings

More long term effects

Question 21

Where are GABA receptors usually found & what is there usual action?

Answer 21

Short interneurons, many in the limbic system

Inhibitory

Question 22

Short interneurons found in the limbic system play a role in….

Answer 22

Emotional responses:
Personal feelings
Emotional memories

Question 23

What is the effect of alcohol on short interneurons?

Answer 23

Removes inhibitory responses

Person becomes upset/aggressive

Question 24

What are the 2 main types of GABA receptor?

Answer 24

GABAa & GABAb

Question 25

Describe the structure of GABAa

Answer 25

Similar to nicotinic cholinergic rec 2 x a subunits 2 x B subunits 1 x y subunit

Question 26

When GABAa is activated, a channel permeable to .... is opened

Answer 26

Chloride | Mem hyperpolarises as GABA rec is inhib

Question 27

Name drugs the GABA receptor's Cl- permeable channel has binding sites for

Answer 27

Benzodiazepines Barbiturates Steroids (Treat anxiety)

Question 28

Describe GABAb rec structure

Answer 28

7 transmembrane domains | Coupled to a G protein

Question 29

What channels do GABAb rec activate?

Answer 29

Outward K+ (cause hyperpol & ipsp) Influence Ca channels

Question 30

What are nAch rec permeable to?

Answer 30

Na+ | Ca2+

Question 31

Name the mAch subtypes

Answer 31

M1- M5

Question 32

What are M1, M3, M5 receptors coupled to?

Answer 32

PLC

Question 33

What are M2 & M4 receptors negatively coupled to?

Answer 33

Adenylyl Cyclase Cause ⬇️ of cAMP upon activation

Question 34

mACh rec degenerate in what disease?

Answer 34

Alzheimer's

Question 35

Dopamine is largely ...... in the CNS

Answer 35

Inhibitory

Question 36

What are the 2 dopamine receptor subtypes?

Answer 36

D1 & D2 | All metabotropic All lead to a G protein

Question 37

Name 2 tracts where dopamine receptors are found

Answer 37

Mesostriatal (formation of organised thought/stabilise mood) Nigrostriatal (voluntary movement)

Question 38

What tract, especially in the basal ganglia, degenerates in Parkinson's?

Answer 38

Nigrostriatal

Question 39

Via which rec does 5HT exert and excitatory effect?

Answer 39

5HT2

Question 40

Via which rec does 5HT exert an inhibitory action?

Answer 40

5HT1

Question 41

What is the action of SSRIs

Answer 41

Block 5HT re uptake 5HT remains active in exerting its effect on post & pre synaptic membranes