2 L5 Postsynaptic Mechanisms 2

Question 1

3 main GPCR ligand types

Answer 1

Neurotransmitters - Hormones - Sensory Signals

Question 2

Define metabotropic

Answer 2

Activates metabolic processes in the cell by working indirectly

Question 3

What is the ligand-receptor interaction mediated by

Answer 3

G proteins - Trimeric GTP proteins

Question 4

True or False- GPCRs act as dimers

Answer 4

True

Question 5

What 2 components do G proteins dissociate into

Answer 5

Ga and B/y

Question 6

What does G protein activation lead to

Answer 6

Activation of membrane bound enzymes and regulation of second messengers

Question 7

Adenyl cyclases

Answer 7

Generates cAMP (2nd mes.) which activates PKA (protein kinase A)

Question 8

Phosphodiesterases

Answer 8

Hydrolysis of cAMP which leads to negative regulation of PKA

Question 9

Phospholipases

Answer 9

Hydrolysis of membrane phospholipids, generation of DAG and IP3 which causes release of Ca from internal stores

Question 10

Dopamine receptor groups

Answer 10

D-1 like- D1, D5
D-2 like- D2, D3, D4

Question 11

D-1 like receptors

Answer 11

Stimulation of adenylate cyclase - Coupled to Gs - Mediate excitatory neurotransmission

Question 12

D-2 like receptors

Answer 12

Inhibition of adenyl cyclase - Coupled to Gi/Go - Mediate inhibitory neurotransmission

Question 13

2 types of enzyme linked receptor

Answer 13

Cytosolic domain with intrinsic enzyme activity
Direct enzyme activity

Question 14

How many subunits does each subunit of an enzyme-linked receptor have

Answer 14

One

Question 15

Where is TrkB located (receptor)

Answer 15

Glia, neuronal cell bodies, presynaptic terminals and on dendrites

Question 16

What binds to TrkB

Answer 16

Brain derived neurotrophic factor (BDNF)

Question 17

BDNF 3 neur-s

Answer 17

Neurotropin - Neuropeptide - Neuromodulator

Question 18

Describe how BDNF is formed

Answer 18

Synthesised as precursor pre pro-BDNF - ProBDNF - mBDNF (matureBDNF)
Both signalling molecules

Question 19

Describe ProBDNF and mBDNF

Answer 19

Pro- Associated with apoptosis and LTD
m- Associated with cell survival and LTP

Question 20

What kind of vesicles is BDNF packaged into

Answer 20

LDCV

Question 21

Are enzyme linked receptors slow or fast acting

Answer 21

Slow acting

Question 22

Describe sites of action for enzyme linked receptors

Answer 22

Presynaptic- Regulation of release
Postsynaptic- Local protein synthesis and Gene expression

Question 23

Is a single NT capable of having multiple actions- explain

Answer 23

Yes- A single NT may have multiple actions through multiple different subtypes located on different cell types

Question 24

Describe GABA synthesis

Answer 24

GABA is an AA but is NOT found in proteins - Synthesised in GABA ergic neurons by GADS

Question 25

Are GABAA receptors specific or widespread

Answer 25

Widespread- Found all throughout the body

Question 26

GABA-A structure

Answer 26

Multiple possible subunits form pentameric chloride ion channels

Question 27

What does activation of GABA gated ion channels cause and how

Answer 27

An IPSP by opening Cl- channels resulting in Cl- influx at synaptic and extra-synaptic sites

Question 28

Describe tonic GABA inhibition

Answer 28

Nearby extracellular GABA binds to extra synaptic GABA receptors and modulates RMP and cell excitability

Question 29

Describe phasic GABA inhibition

Answer 29

GABA is released from presynaptic terminals and binds to postsynaptic GABA receptors

Question 30

Anxiety and GABA

Answer 30

People with anxiety have reduced GABA activity- reduced inhibition

Question 31

Muscarinic Ach receptor

Answer 31

Metabotropic GPCR- Sensitive to muscarine- Found in Glia, heart muscle, salivary glands

Question 32

Nicotinic Ach receptor

Answer 32

Ionotropic Ligand gated ion channel - Sensitive to nicotine - Mediate fast synaptic transmission - High density in NMJ

Question 33

Ach synthesis and degradation

Answer 33

Choline taken up into nerve terminal - Ach synthesised by choline acetyltransferase - Ach transported into vesicles - Ach degraded by acetylcholinesterase