Opioids Flashcards Preview

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Flashcards in Opioids Deck (27):
1

How many types of opioid receptor are there

4

2

What are the names of each of the opioid receptors

MOP (mu)
DOP (delta)
KOP (kappa)
NOP (nociceptor)

3

What are the downstream events of the opioid receptors

All the same. Coupled to a G[i/o] protein.
Decreases adenylyl cyclase and calcium
Increases potassium

4

What types of receptors are ionotropic

Voltage/ligand gated
inc. GABAa

5

What types of receptors are metabotropic

GPCRs
inc. GABAb

6

What is the structure of a Voltage-Activated Calcium Channel

24 TM proteins split into 4 helices. Voltage activation occurs in the fourth helix.
Composed of alpha 1 (24TM); alpha 2; beta; gamma and delta subunits

7

Which types of voltage-activated calcium channels are involved in opioid reception

P/Q and N

8

How can calcium currents be recorded

Patch clamp technique.
Micropipette clamps onto the region of interest. Suction. Record.
Can detect whole cell or part of a cell.

9

What are the three types of anaesthetic

Local - close to pain source
Central - through central/spine sites
General - loss of consciousness and/or analgesia. Acts on GABA receptors.

10

Give some examples of opioid analgesic drugs used

Codeine
Tramadol
Morphine
Methadone/Oxycodone

11

How can the MOPr lead to analgesia

Inhibition of calcium channels. Present on neurones. By blocking calcium release, signal cannot reach the brain and create pain.

12

What effects can inhibiting opioid receptor activity have

Reduction of addictive behaviour (drugs/food/gambling etc)

13

How can opioid receptors influence dopamine levels

MOPr activation (specifically GAPA receptors) dis-inhibits dopamine neurons in the reward pathway.

14

How many types of arrestin are there

4 (arrestins 1-4)
Arrestin 2 and 3 = beta-arrestin 1 and 2..

15

What is the barcode hypothesis

I DONT KNOW THIS LOOK IT UP.

16

What are the opioid effects in vivo

Analgesia
Respiratory depression
Immunosuppression
Constipation
Hyperalgesia (pain resistance)
Tolerance
Reward -> addiction
In rats; increased locomotion

17

What happens in MOR knockout mouse

None of the opioid effects are displayed.
Importantly; no tolerance.

18

What is the molecular basis for drug tolerance

Beta-arrestin.
Shown in beta-arrestin knockout mice

19

What happens in a beta-arrestin knockout mouse

No drug tolerance.
Thought that morphine creates greater 'reward'
Reduced morphine stimulated locomotion

20

How many types of dopamine receptors are there

5, but two main types
D1- like (D1/5)
D2- like (D2/3/4)

21

What does dopamine regulate in the body

Locomotion, cognition, reward, emotions and endocrine function

22

Give examples of disorders that are dopamine dependent

Schizophrenia, bipolar, depression, Parkinsons, and drug abuse/dependence

23

Where is Dopamine synthesised

In specific neurones by tyrosine hydroxylase (TH)

24

Where can dopamine neurones be found

Mainly in brain pathways (with long complicated names..)

25

What is the difference between DA1-like and DA2-like receptors

DA1- like activate adenylate cyclase (involved in ERK/RAF/MEK; and lead to ERK1/2 activation)
DA2-like inhibit adenylase cyclase (involved in PP2A/AKT; lead to GSK3 inhibition)
They have very different signalling pathways.

26

What happens in a dopamine knockout mouse

No morphine stimulated locomotion
Still exhibit morphine reward (so other pathways must be involved)

27

What is morphine stimulated locomotion dependent on

DA1-like receptor activation of ERK