Opioids Flashcards
define analgesia
no pain felt even though there is painful stimuli
what are the neurotrans released by descending pain inhibitory tracts
serotonin
enkephalin
NE
endgenenous opioid peptides
enkaphlins
endorphins
dynorphins
what are the opioid receptors
mu receptor
kappa receptor
delta receptor
what binds to the mu receptor endogenously
enkaphlins, beta endorphins
what does binding of ligand to the mu, kappa, and delta receptors cause?
activation of Gi, which inhibits adenylate cyclase, decreasing cAMP—net result is decreased release of neurotransmitters
where are opioid receptors found?
periaquaductal gray dorsal horns of sp cord medulla hypothalamus GI heart
what receptors and in what location may be involved in drug dependence
mu and delta receptors in limbic areas
what receptors and in what location may be involved in dysphoria
kappa receptors in limbic areas
definition of narcotic
morphine like drugs and other abused substances
induce sleep like state and could or could not be analgesic
opioid metabolism
by liver
analgesic effect-compare among opioids
full agonists equally effective, except codeine and propxyphene
what effects do opioids have
analgesic
cough supression: codeine, dextromethorphan. Dextromethorphan doesn’t bind to opioid receptors
antidiarrheal, constipation (mu receptors on GI nerves)
euphoria, followed by sedation
respiratory depression (due to reduced sensitivity of brainstem chemoreceptors to CO2)
nausea (through activating chemoreceptor trigger zone in area postrema)
endocrine: reduces LH release (mu), increases ADH production (mu), decreases ADH secretion (kappa)
miosis (activates Edinger Westphal nucleus)
tolerance
physical dependence
tolerance in opioids rapidly, more gradually, and doesn’t develop for what?
rapidly: nausea and vomiting
gradually: analgesia, euphoria, respiratory depression, endocrine effects
no tolerance develops for: miosis, constipation
cross tolerance for opioids develops with what?
other mu agonists
