BIOM 3090 Lecture Notes - Lecture 20: Papaver Somniferum, Opioid Receptor, Cough Medicine
9 Jun 2018
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Opioids
Opioids as pre-meds
- General anesthetics produce unconsciousness but do not inhibit pain signal
generation or propagation
- Patients do not feel mildly painful surgical manipulations (e.g. a skin
incision) simply because they are unconscious
- Mild surgical manipulations produces only small numbers or pain signals,
which are transmitted to the Reticular Activating System (RAS) in the
medulla, but are insufficient to awaken the patient
o RAS: wake you up when something bad is happening
o Opioids: good for oppressing pain
- If surgical manipulations produce large numbers of pain signals, the RAS may
be stimulated to the point where the anesthetized patient begins to awaken
- We can prevent this by administering an analgesic beforehand to inhibit pain
signal generation
- This is safer than trying to maintain unconsciousness using higher doses of
general anesthetic (most of which inhibit respiration & CVS function in a
dose-dependent manner)
- Painful manipulations → possible arousal → prevent with analgesic
Opioids
- Opium poppy: seed pod juice dried & powdered → opium
- Opium contains: morphine, codeine, heroin, hundreds of other chemicals
- Terminology:
o Opiate – natural component of opium
o Opioid – any opiate or synthetic derivative
- The body produces several endogenous opioids, each of which stimulates
most opioid receptor types
o E.g. endorphins, enkephalins, dynorphins, endomorphins,
morphiceptin, nociception, orphanin FQ, etc.
- Opioids drugs are used for
1) Analgesia: management of moderate to severe pain
2) Sedation
3) Cough suppression: Antitussive
4) Treatment of diarrhea: constipation is a major side effect of most opioids
Opioid receptor families
- There are several opioid receptor families
o Three mediate analgesia
▪ Mu ()
▪ Delta ()
▪ Kappa ()
o A related receptor type produces dysphoria
▪ Sigma ()
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Document Summary
General anesthetics produce unconsciousness but do not inhibit pain signal generation or propagation. Patients do not feel mildly painful surgical manipulations (e. g. a skin incision) simply because they are unconscious. If surgical manipulations produce large numbers of pain signals, the ras may be stimulated to the point where the anesthetized patient begins to awaken. We can prevent this by administering an analgesic beforehand to inhibit pain signal generation. This is safer than trying to maintain unconsciousness using higher doses of general anesthetic (most of which inhibit respiration & cvs function in a dose-dependent manner) Painful manipulations possible arousal prevent with analgesic. Opium poppy: seed pod juice dried & powdered opium. Opium contains: morphine, codeine, heroin, hundreds of other chemicals. Terminology: opiate natural component of opium, opioid any opiate or synthetic derivative most opioid receptor types. The body produces several endogenous opioids, each of which stimulates: e. g. endorphins, enkephalins, dynorphins, endomorphins, morphiceptin, nociception, orphanin fq, etc.
