Lecture 4.1 Flashcards

1
Q

What are the 3 ways Metabotropic receptors regulate ion channels?

A
  1. Coupling of G protein to an ion channel altering permeability
  2. Coupling of G protein to a 2nd messenger where it directly regulates an ion channel ex/ cAMP/cGMP
  3. Coupling of G protein to a 2nd messenger leading to ion channel phosphorylation
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2
Q

What are the alpha subunit types of Metabotropic receptors and what do they do?

A

G(alpha)s- stimulates Adenylyl Cyclase
G(alpha)I- inhibits Adenylyl Clyclase
G(alpha)q- stimulates Phospholipase C
G(alpha)t- inhibits cGMP Phosphodiesterase

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3
Q

G Protein effector pathways (G protein to Adenylate Cyclase)

A

G Protein- AC-cAMP-PKA (Kinase)

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4
Q

G Protein effector pathways (G protein-PI3 Kinase)

A

G Protein-PI3 Kinase-Pi3 phosphate-PKB(Kinase)

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5
Q

G Protein effector pathways (G Protein-Phospholipase C)

A

G Proetin-Phospholipase C- DAG/IP3-PKC and CaCam Kinase respectively

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6
Q

G Protein effector pathways (GProtein-Guanylate Cyclase)

A

G Protein-Guanylate Cyclase-cGMP-PKG(Kinase)

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7
Q

If signalling is recurrent for a long time what is one thing that could happen?

A

Gene expression-when cAMP is increased for a longer period, protein kinase A is activated and will go into the nucleus and work with the CREB cycle to increase gene expression

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8
Q

How are receptor signals switched off?

A

Detachment of ligand
Hydrolysis of GTP back to GDP
Removal of 2nd messengers (could be removed or destroyed)
Activation of phosphorylases

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9
Q

Is switching off receptor signals easier or harder then turning them on?

A

Switching off is harder and more complicated

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10
Q

How do peptide neurotransmitters get to the axon terminal?

A

They are synthesised and packaged in the cell body, transported along outside of micro tubules and undergo exocytosis in response to increase in calcium influx. They is also no re-uptake of them

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11
Q

Are peptide neurotransmitters ionotropic of Metabotropic?

A

Metabotropic

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12
Q

What are some examples of peptide neurotransmitters?

A
Angiotensin II (thirst and salt appetite)
Endorphins
Substance P (pain transmission)
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13
Q

Vesicles with peptide transmitters are called?

A

LDCVs- Large Dense Core Vesicles

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14
Q

What else are inside peptide neurotransmitter vesicles?

A

Proteins that act as a scaffolding and sometimes peptidases that may act after the release of the neurotransmitter

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15
Q

What do Neuromodulators do?

A

They alter excitability of the post synaptic neuron but do not regulate the membrane voltage

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16
Q

What are co-transmitters?

A

They are often peptides, are released from the same synapse as a fast neurotransmitter, co-released

17
Q

What are auto receptors?

A

They are present on the pre-synaptic terminal and inhibit release of neurotransmitter

18
Q

What are non-synaptic receptors?

A

They are an example of Neuromodulators action, located on the outside of the synapse

19
Q

In relation to each other, are Metabotropic receptors spread closely or far apart from each other?

A

More spread out, less dense post synaptic density

20
Q

Describe the process of desensitisation

A

When a signal needs to be stopped, a Kinase phosphorylates GRK. This in turn phosphorylates the GPCR. This then binds Arrestin stopping the GPCR

21
Q

Is it the receptor or the transmitter that determines the nature of neurotransmission?

A

The receptor!

22
Q

Transmitters like catecholamines and peptides are ………………transmitters

A

Metabotropic

23
Q

What is a property of the Muscarinic ACh receptor that is interesting

A

It bind to ionotropic (Nicotinic) and Metabotropic receptors (Muscarinic)

24
Q

What is the effect of Metabotropic stimulation?

A

Alters ion channel permeability

Slower on set and longer duration then ionotropic