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65 Cards in this Set
- Front
- Back
What is pain?
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An unpleasant sensory or emotional experience usually associated w/ actual or potential tissue dmg
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What is analgesia?
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A state in which no pain is felt despite the presence of a stimulus which is normally painful.
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What are Analgesics?
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Drugs that alleviate pain without impairing other sensory modalities.
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What are pain receptors called?
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Nociceptors
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What nerve fibers mediate
-Sharp localized pain -Dull, diffuse, ache/burn |
Sharp = A-delta fibers
Dull = C fibers |
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Where in the spinal cord dorsal horn do they terminate:
-Adelta fibers -C fibers |
Adelta = in lamina I
C fibers = in lamina II |
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What is the pain mediated by Adelta and Cfibers called, and what NT is used in the spinal cord laminae I/II?
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Adelta: Somatic - Glutamate
Cfiber: Visceral - Glutamate and Substance P |
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After the primary synapse of Adelta and Cfibers in the dorsal horn of the SC, where do the 2ndary neurons project?
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To the thalamus
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What are the ascending 2ndary neurons that mediate pain to the thalamus called?
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Spinothalamic tracts
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To what 3 sites do the pain sensations project after the thalamus?
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-Limbic system
-Sensory/association cortex |
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What other tracts are involved in pain?
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Descending tracts
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Where do the descending pathways originate?
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-Periaqueductal gray region of the midbrain
-Nuclei of rostro-ventral medulla |
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Where do the descending pathways synapse in the spinal cord? What is the tract in the SC called?
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-Dorsolateral funiculus
-Terminates in the dorsal horn on ascending pain pathways |
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What do the descending pathways release, and what is their effect on ascending pain pathways?
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-RElease NE, 5HT, Enkephalin
-Inhibit ascending pain |
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So what is the NT released by Adelta or C fibers when they synapse in the laminae I/II?
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Glutamate - excitatory
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What is the effect of serotonin release by descending fibers?
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Excitatory - stimulates Enkephalin release
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What effect do Enkephalin, Serotonin, and Norepinephrine all have on the ascending pain pathway activity?
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Inhibitory
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Where do the majority of narcotic analgesics work?
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At descending pain pathways to inhibit pain perception
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What are the 3 basic families of ENDOGENOUS opioid peptides?
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-Enkephalin
-B-Endorphin -Dynorphin |
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What is the Enkephalin precursor?
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Proenkephalin
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Where are Enkephalins distributed?
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Widely throughout the CNS especially in interneurons associated with pain pathways
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What is the Endorphin precursor?
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Proopiomelanocorton (pomc)
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Where are B-endorphins distributed?
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-Hypothalamus
-NTS -Anterior pituitary |
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How do the B-endorphins in the anterior pituitary behave?
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Co-released with ACTH in response to stress
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What is the Dynorphin precursor?
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Prodynorphin
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Where are longerchain dynorphins located?
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-Colocalized with Vasopressin in hypothal and posterior pituitary
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Where are shorter chain dynorphins located?
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In CNS pain pathways in the spinal cord
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How many opioid receptors are there, and to what superfamily do they all belong?
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THREE - all are GPCR's
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What are the 3 opioid receptor classes?
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-Mu
-Kappa -Delta |
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What is the G protein coupled to all 3 of the opioid receptors?
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Gi
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What are the 3 opioid receptors?
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-Mu
-Delta -Kappa |
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Where are Mu and Delta receptors located? What might this be responsible for?
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In limbic areas - may be responsible for drug dependence
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Where are Kappa receptors located? What might this be involved in?
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In limbic areas - may be involved in dysphoria
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What is the natural endogenous ligand of Mu receptors?
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-B-endorphin especially
-Enkephalins also |
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What is the natural endogenous ligand of Kappa receptors?
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Dynorphin
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What is the natural endogenous ligand of Delta receptors?
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-Enkephalins mostly
-B-endorphin also |
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How many drugs are agonists of the Mu receptor? What acronym is for them?
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7 - MMMFOCH
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What is MMMFOCH
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-Morphine
-Methadone -Meperidine -Fentanyl -Oxycodone -Codeine -Heroin |
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What are the 2 antagonists of the mu receptor?
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-Naloxone
-Naltrexone |
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What is the main Kappa receptor drug to know?
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Nalbuphine
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Where is the Delta receptor well known for being localized in addition to limbic areas?
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Vas deferens
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What is the drug ligand of the delta receptor?
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There are none
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What does the term "Narcotic" refer to?
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-Morphine like drugs
-Some other abused substances |
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What effects do narcotics produce as drugs?
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-Stuporous sleeplike state
-May or may not be analgesic |
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What is a better term than Narcotic, why?
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Opiate - because these are what there are actually receptors to - there are no "narcotic" receptors
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What are Opiates?
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Drugs derived from opium or have a morphine-like pharmacologic profile
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What is the definition of Opioid?
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Referring to ALL opiates, agonist-antagonists, and endogenous peptides.
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How are opioids administered?
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Can be parenteral or oral based on how much FPE they are subject to
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What 2 opioids particularly undergo extensive FPE?
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-Morphine
-Naloxone |
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How much lower is the oral potency of Morphine and Naloxone due to their high FPE?
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1/3 that of parenteral potency
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How do you overcome the low oral potency and bioavailability of Morphine and Naloxone?
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just give MORE
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What IS morphine?
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Opioid agonist of Mu receptor
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What IS naloxone?
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Opioid antagonist of Mu
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What is the onset of action of opioids determined by?
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Their lipophilicity
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Which has higher lipophilicity; heroin or morphine?
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Heroin!
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What 2 factors determine the duration of action of opioids?
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-Lipophilicity
-Rate of elimination |
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How does lipophilicity affect duration of drug action?
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The more lipophilic, the faster it will redistribute away from its active site.
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What is important to remember about the metabolism of some of the opioids?
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Metabolism will produce active drugs
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What are 2 opioids that are converted to active drugs by metabolism?
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-Codeine
-Heroin |
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What is the structure of Heroin and its active metabolite?
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Heroine = Diacetylmorphine
Metabolite = monoacetylmorph |
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What is the mechanism by which the opioids are metabolized?
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Common mechanisms - to increase polarity and decrease activity
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How many effects do the opioid agonists have? Acronym?
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NINE - ScARE SPENC
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What are the nine effects of the Opioid agonists?
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-Suppress cough
-Analgesia -Respiratory depression -Euphoria -Sedation -Pupil constriction -Endocrine effects -Nausea -Constipation |
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What are 2 ways in which the opioid agonists are analgesic?
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-Decrease pain perception
-Decrease appreciation of pain |
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What type of pain do the opioids alleviate?
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Nociceptive - NOT neuropathic
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