Opioids

Question 1

Where can we find opioids

Answer 1

Opium poppy seed
Codeine (Cough Syrup)
Oxytocin
Pentanol

Question 2

What is a neurotransmitter that blocks opioid receptors

Answer 2

Naloxone (antagonist) of heroin. Found in narcan ( medication given to people who OD on heroin). Mu receptor antagonist
Buprenorphine- Kappa receptor antagonist
Methadone - partial Kappa agonist

Question 3

Opioid receptors in brain

Answer 3

Mu
Kappa
Delta

Question 4

What do endogenous opioids do

Answer 4

A) Open K+ channels presynaptically ( opioid binding to NT ends up in G modulation of receptor opening up K+ resulting in hyperpolarization, decreasing firing)
B) Axonic signaling closes Ca2+ channels( Binding to receptor leads to G modulation closing the Ca2+ channels, this reduces firing of the NT)
C) presynaptic autoreceptors reduce transmitter release ( Endorphin autoreceptor decrease release of cells NT, neuron with NT + opioid bind to NT reducing the post synaptic effect of the drug)

Question 5

Pain

Answer 5

Early Pain -> first sharp initial pain (ex. burning) carried out by myelinated A delta fibers
Late pain -> symptoms from early plain + plus prolonged pain (burning + throbbing of finger) carried out by unmyelinated C fibers
-Opioid neurons reduce pain by inhibiting pain neurons in spinal cord

Question 6

PAG (Opioids + Reward)

Answer 6

-Opioid neurons (inhibitory) bind to GABA neurons (inhibitory) which are either binded to NE neurons in the Locus Correlus (LC) or Serotonin neurons in the (Raphe Nuclei) -> opioids inhibit the inhibition of GABA -> serotonin and NE can then go on to inhibit spinal cord pain receptors

Question 7

What does Morphine do

Answer 7

Morrphine is a Mu angonist. Increases the amount of dopamine in the system

Question 8

Dopamine reward pathway

Answer 8

VTA -> Nucleus Accumbens -> Ventral Pallidum
GABA -> Mu-> DA/ Kappa -> dopamine release in Ventral Pallidum

Question 9

Tail of VTA

Answer 9

is Gabaergic and is rich of opioid receptors

Question 10

Desensitization causes

Answer 10

Tolerance

Question 11

cAmp in morphine treatment

Answer 11

• opioid receptor activation reduces cAMP
  -withdrawl overproduces cAMP
  -cAMP is important for addiction because it activates the CREB protein which leads to stronger synapses which changes the gene expression in the brain (Which forms addiction)