Opioids (Pharmacology)

Question 1

Opioid MA

Answer 1

They produce their actions at a cellular level by
activating opioid receptors.

They relieve dull, poorly localised pain transmitted by the paleospinothalamic system and are relatively ineffective for the relief of sharp, localised pain.

Question 2

Opioid Receptor Location

Answer 2

High concentrations in the peri-aqueductal grey area (PAG), limbic system,
thalamus, hypothalamus, medulla oblongata and substantia gelatinosa of the spinal cord

They belong to the G-protein coupled receptor family

Question 3

Three Opioid Receptor Groups

Answer 3

Encephalins
Dynophorins
Endorphins

2mu
3kappa
2delta

sigma no longer classified due to dysphoric effects

Question 4

Opioid Receptor functions

Answer 4

µ1 receptors - analgesia and euphoria

µ2 receptors - present in brain and GIT and is involved in respiratory depression and constipation

Κ receptors - contribute to spinal analgesia and also sedation

δ receptors - analgesia

Question 5

Opioid Classification

Answer 5

Pure agonists
e.g. morphine, pethidine, fentanyl

Dualists / partial agonists
e.g. Pentazocine, buprenorphine

Competitive antagonists
e.g. Naloxone, Naltrexone