N14 - Analgesics - opioids

Question 1

families of opioid receptors

Answer 1

Families:
- mu - most opioids - bind and stimulate; endorphins bind here
- kappa - dynorphins bind

Question 2

Opioids bind where?

Answer 2

bind to specific opioid receptors in the CNS. Mimic endogenous opioid peptides (endorphins, enkephalins, and dynorphins

Question 3

MoA of Opioids

Answer 3

• inhibitory G proteins that inhibits adenylyl cyclase
• two main actions:
  1. - post-syn: opening K+ channels, causing membrane hyperpolarization
  2. pre-syn: closing Ca++ channels on presyn membranes to inhibit NT release
• block of neuronal firing, prevention of NT release.

Question 4

Distribution of receptors

Answer 4

• dorsal horn of spinal cord - all three receptors found in high concentrations
• periphery: primary mu receptors