Synapse

Question 1

What does the ANS mainly regulate?

Answer 1

Contraction & Relaxation of smooth muscle
Exocrine systems
Heartbeat
Energy Metabolism

Question 2

Which neurotransmitter regulates the sympathetic (fight or flight) nervous system?

Answer 2

Noradrenaline

Question 3

Which neurotransmitter regulates the parasympathetic (rest or digest) nervous system?

Answer 3

Acetylcholine

Question 4

Where does Acetylcholine (Ach) work?

Answer 4

Somatic NS
Parasympathetic NS
Limited Sympathetic NS

Question 5

Where does Noradrenaline (NA) work?

Answer 5

Sympathetic NS

Question 6

Where does Dopamine (DA) work?

Answer 6

CNS - Reward pathway

Question 7

Where & how does Glutamate (GLU) work?

Answer 7

Main excitatory CNS neurotransmitter

Question 8

Where & how does Gamma-amino butyric acid (GABA) work?

Answer 8

Main inhibitory CNS neurotransmitter

Question 9

What does Serotonin control?

Answer 9

Sleep, Wakefulness & mood

Question 10

What is Depolarisation & Repolarisation?

Answer 10

Depolarisation - influx of Na+ - towards Ena = + 60 mV

Repolarisation - Efflux of K+ - towards Ek = -84 mV

Question 11

What happens when the neurotransmitter interacts with the Ionotropic receptor?

Answer 11

Activation causes influx of Na+ in post-synaptic terminal

Depolarisation occurs

AP is created (Signal propogation)

Question 12

What happens when the neurotransmitter interacts with the Metabotropic receptor?

Answer 12

Triggers second messenger signalling cascades

Triggers functional responses ( e.g. muscle contraction)

Question 13

How is further release of Ca2+ stopped?

Answer 13

When neurotransmitter reaches sufficient conc. in synaptic cleft

It activates pre-synaptic receptors

Sends negative signal into pre-synaptic terminal

Thus stopping further release of Ca2+

Question 14

How is the signal terminated?

Answer 14

Reuptake of neurotransmitter into pre-synaptic terminal by use of monoamines

OR

Degradation of neurotransmitter in synaptic cleft by use of Acetylcholine

Question 15

Which areas would be suitable for drug targeting in the synaptic transmission pathway?

Answer 15

1. Synthesis
2. Storage of neurotransmitter
3. Neurotransmitter release
4. Receptors
5. Neurotransmitter termination

Question 16

What are unprotected monoamines broken down by?

Answer 16

Monoamine Oxidase (MAO)

Question 17

What is Reserpine’s MOA?

Answer 17

Prevents packaging monoamines into vesicles

Thus exposing them to MAO

Question 18

What are ionotropic receptors?

Answer 18

Ligand-gated ion channels made up of many subunits

They mediate fast synaptic channels

Question 19

What are Metabotropic receptors?

Answer 19

G protein coupled receptor (GPCR)

They mediate slower synaptic transmission - secondary messenger cascades

Question 20

How are secondary messenger cascades initiated?

Answer 20

Agonist activates GPCR - causes a conformation change - exposes GDP/GTP exchange sites of G protein

Hydrolysis of GTP-GDP releases energy = which enables dissociation of alpha subunit from beta-gamma subunits

Which initiates secondary messenger cascades

Question 21

What are the 3 main types of G proteins?

Answer 21

Gq - Stimulatory
Coupled to Phospholipase C

Gs - Stimulatory
Coupled to Adenylyl Cyclase

Gi- Inhibitory
Coupled to Adenylyl Cyclase

Question 22

What class is Fluoxetine and what does it do?

Answer 22

Selective Serotonin Reuptake Inhibitors (SSRI)

Prolongs presence of Serotonin around post-synaptic receptors

by preventing reuptake of Serotonin

Question 23

What drug class is Moclobemide and what does it do?

Answer 23

MAO inhibitor

Prolongs presence of Serotonin

by inhibiting Monoamine Oxidase A