Endogenous opioids Flashcards
Where are oxytocin & vasopressin synthesised?
In the hypothalamus
Where are most neurotransmitters synthesised?
In the synaptic cleft
Where are neuropeptides synthesised?
Synthesised in the cell body
Why is it difficult to use peptides as drugs?
- Difficult to pass the blood-brain barrier
- Peptides are broken down in the gut
List the opioid receptors
Mu (MOP)
Delta (DOP)
Kappa (KOP)
NOP (nonclassical opioid receptors)
What is a characteristic of a ‘classical’ opioid receptor?
Its effects are blocked by naloxone
Which area of the brain is packed with opioid receptors?
What does this area stimulate when activated?
PAG
Stimulates the descending inhibitory neurons
What effects does enkephalins have pre and post synaptically?
Presynaptically : Blocks release of glutamate and substance P
Post-synaptically: Inhibits the stimulation of neighbouring neurons
What are the functions of opioid peptides? (regulations)
Pain, Emotion, Reward
Endogenous opioid stimulates rewards:
Reward centre of the brain
Dopamine is released in the nucleus accumbens
It activates the reward system
Endorphins stimulate reward through Mu receptors (they inhibit the release of GABA which prevents inhibition of dopamine)
What are the roles of oxytocin?
Milk ejection and uterine contractions
