Exam #01b (Opiates & Opioids) Flashcards
A peripheral nerve for the reception and transmission of painful stimuli is called what?
Nociceptor
What is the difference between perception and modulation?
Perception is the brains INTERPRETATION of a stimulus
Modulation is the bodies or drugs EFFECT ON PERCEPTION
This type of drug reversibly depresses neuronal function, producing analgesia, amnesia, and akinesia (loss of power of voluntary movement)?
Anesthetics
This type of drug, in moderate doses, dulls the senses, relieves pain, and induces sleep but in excessive doses causes stupor, coma, or convulsion?
Narcotics
True or False - opioid analgesics reduce the perception of pain WITHOUT a loss of consciousness?
True
What is the principle alkaloid extracted from opium poppy? What is extracted to a lesser extent?
Morphine (and to a lesser extent codeine)
What was opium historically used for?
constipating action
What is the principle alkaloid in the other poppy plant where opioid drugs are derived from?
Thebaine
True or False - thebaine is a convulsant drug that produces NO ANALGESIA and NOT USED CLINICALLY?
True - it’s an important synthetic intermediate in the production of semi-synthetic opioids
True or False - morphine has a high addiction liability?
True
What therapeutic effect is common to opioids acting at both mu and kappa receptors?
analgesia
What major difference in side effects is noted between mu and kappa opioid receptors?
binding at MU - produces EUPHORIA
binding at KAPPA - produces DYSPHORIA
Binding at which opioid receptor subtype is responsible for the following SE: constipation, respiratory depression?
mu
Explain the MOA of morphine binding to a mu receptor?
- morphine binds to mu receptor (7TM-GPCR) on a presynaptic terminal
- activates INHIBITORY G-protein (Gi)
- decrease in adenylate cyclase activity
- decreased [cAMP]
- leads to decreased Ca2+ influx at presynaptic terminal
- which results in decreased NT release (glutamate, substance P, etc.) and hyperpolarized pain afferent
- decreased pain fiber activity
Morphine also binds to mu receptor (7TM-GPCR) on a postsynaptic terminal which goes through the same pathway above, except it increases K+ efflux rather than decreasing Ca2+ influx. It still results in decreased pain transmission
List the (6) indications for opioids?
- moderate to severe pain (analgesia)
- cough (antitussive)
- diarrhea (antidiarrheal)
- acute pulmonary edema
- anesthesia
- addiction (ex. methadone)