CPTP 3.20 - Opiods

Question 1

Name three functions opiotes have on the body?

Answer 1

1. Change limbic system (Dopa projections) = control emotions and pleasure
2. Block pain messages transmitted by the spinal cord
3. Change the brainstem (pons and medulla) - areas that control the ANS

Question 2

What three things happen with opiod receptor activation?

Answer 2

Inhibition of neuronal firing
Inhibition of neurotransmitter release
Dis-inhibition - removal of inhibitory influence (GABA) = excitation

Question 3

Name four areas where opiods interact with opiod receptors to elicit therapeutic effects?

Answer 3

Limbic areas
Medulla
Periaquaductal grey
Dorsal horn of spinal cord

Question 4

Name the three opiod receptors and state their activities?

Answer 4

Mu (μ) - analgesic effects in the brain
Kappa (κ) - analgesic effects in the spinal cord
Delta (δ) - Interact with endogenous enkephalins and mediate CNS effects

Question 5

What two effects do all the opiod receptors have in common upon activation?

Answer 5

Anti-nocioception

Meiosis (contraction of pupils)

Question 6

Name three classes of endogenous opiods?

Answer 6

Proopiomelanocortin = B-endorphin (Mu)
Proenkephalin = Met-enkephalin and Lue-enkephalin (Delta)
Prodynorphin = Dynorphin A and Dynorphin B - Kappa ONLY

Question 7

Name four opiod (agonist) analgesics?

Answer 7

Morphine
Dimorphine (heroin)
Codiene
Tramadol

Question 8

Describe how morphine works?

Answer 8

Mu and delta receptor AGONIST

Metabolism by glucoronidation

Question 9

Describe how tramadol works?

Answer 9

Mu opiod receptor AGONIST

Also inhibits the re-uptake of 5HT and Nor epi

Question 10

Describe how addiction occurs with opiod analgesics?

Answer 10

Reward = due to tolerance users increase the dosage to obtain the high - As more drug is taken the withdrawal state with dependency increases = Negative Re-inforcement

Question 11

How does diamorphine work?

Answer 11

Activation of Mu opiod receptor on GABA inter neurone in the ventral tegmental area leading to the inhibition of GABA release = Increased Dopa in the nucleus accumbens