Opioid Analgesics Flashcards
Where do opioids act most effectively?
at 1˚-2˚ afferent synapse
What is an example of an endogenous opioid?
endorphines, endomorphines
What are the three opioid receptor types?
mu
kappa
delta
Functions of mu receptor
analgesia
respiratory suppression
decreased GI motility
Functions of kappa receptor
analgesia
sedation
decreased GI motility
Functions of delta receptor
modulation of mu receptor
ORL-1 receptor
structurally similar to mu but insensitive to opioid analgesics
What type of receptor are mu, kappa, and delta opioid receptors?
G-protein coupled receptors
What are the primary actions of the mu receptor?
K+ channel activation in pre- and postsynaptic neurons
—>prevents depolarization
Ca2+ channel inhibition in presynaptic neurons
—>prevents NT release
The release of what NTs is blocked by Ca2+ activation?
glutamate and substance P
What receptor types does morphine primarily work on?
mu and kappa
Why is heroin faster acting than morphine?
more lipid soluble, crosses BBB more easily
What opioid antagonist is used in acute overdoses of opioids?
naloxone
What opioid antagonist is used in opioid addiction patients?
naltrexone
What are the two types of important opioid metabolites found in circulation?
pharmacologically active
toxic
