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Flashcards in Chronic receptor modulation Deck (20):
1

What are Micro RNAs (miRNAs)

19-24 nucleotides long
Double stranded
Enables sequence-specific inhibition.
They are highly stable and transported between cells by microvesicles)

2

Define deactivation

Loss of gating by removal of activation signal (ligand or voltage)
(signal gone; response stops)

3

Define desensitisation

Loss of gating after activation signal is removed.
(response continues even when signal has gone)

4

Explain desensitisation in the context of the 5-HT receptors in guinea pigs

Response is lost after prolonged exposure to 5-HT. This is not because of endocytosis of the receptor.
5-HT is moved into cells and is slowly released. This prevents desensitisation recovery (though cannot cause desensitisation on its own) - Resensitisation is blocked by low levels of 5-HT

5

What is palonosetron and how does it work

It inhibits 5-HT3 receptors (pseudo-permanent antagonist). Has high affinity for the receptors. Used in radiotherapy and chemotherapy-induced emesis.
Receptors can recover, but by replacement of receptors with new [unbound] receptors.

6

How does the GABAa receptor undergo endocytosis

Clathrin and AP (adaptor protein) 2 complex mediates endocytosis. This is to regulate the number of receptors available at the cell surface.

7

Where are GABAa receptors usually delivered to/removed from

Extrasynaptic sites

8

What does LTP stand for

Long Term Potentiation

9

What are the causes of early phase LTP

Phosphorylation and trafficking

10

Give some examples of RNA modification

Deaminase
GluR2 editing (of the gene RNA)

11

What are pharmacological chaperones

Secreted transmembranal proteins. Found in ER, Goigi, Lysosomes, Surface.

12

Give some examples of pharmacological chaperones found in the ER

Calnexin
Protein disulphide isomerases (PDI)
BiP

13

Give some examples of co-translational process in the ER

Protein glycosylation
Disulphide bond formation
Protein folding and oligomerisation

14

What do glycosylated proteins have to do to get out of the ER

One step - requires glucose removal. Policed by calnexin (pharma chaperone)

15

Why is disulphide bond formation important

Occurs co-translocationally
Important for forming tertiary structure
Chaperone = Protein disulphide isomerases (PDI)

16

What role do Calnexin and BiP have in RNA modifications

Act on immature proteins.
Specifically on Monoglucosylated sugars (calnexin) and Hydrophobic domains (BiP).
Fixes up the protein just before it leaves the ER to go into the cytoplasm.

17

What is KDEL

Present in ER and Golgi. Includes BiP, Calnexin and PDI

18

What are assembly signals

Intracellular signals that drive subunit-subunit interactions. (in receptors). Highly conserved

19

Give some examples of chemical chaperones

Glycerol
DMSO
Low temperature? (slows processes down so higher success rate)

20

What is bicuculline

A competitive antagonist of the GABA receptor