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VetMed Pharmacology9
Opioid Pharmacology
| Question | Answer |
|---|---|
| Amino-Terminal End of Opioid Peptides | Tyr-Gly-Gly-Phe-(Met or Leu) |
| Classes of Endogenous Opioid Peptides | endorphins enkephalins dynorphins nociceptin & orphanin (N/OFQ) |
| Anatomical Distribution of Endorphins | arcuate nucleus nucleus tractus solitarius pituitary pancreatic islet cells |
| Anatomical Distribution of Enkephalins & Dynorphins | distributed widely throughout CNS |
| Functions of Enkephalins & Dynorphins | pain perception behaviour modulation autonomic nervous system regulation motor control neuroendocrine function |
| Anatomical Distribution of Nociceptin & Orphanin | hippocampus cerebral cortex sensory sites |
| Functions of Nociceptin & Orphanin | complex behavioural profile pain sensitivity |
| Telencephalon | amygdaloid body hippocampus cingulum and cingulum gyrus septal region medial forebrain bundle - hypothalamus |
| Diencephalon | thalamus hypothalamus |
| Mesencephalon | intercrural nucleus reticular formation |
| Opioid Receptor / Opioid Dose Concept | compounds that are relatively selective in their binding avidity for u, o, or k receptors at "standard" doses eventually "spill-over" and also bind to other opioid receptors at higher concentration |
| Location of Opioid u Receptors | periaqueductal gray matter (pain) pontine reticular formation median raphe nucleus raphe magnus spinal cord ' |
| Location of Opioid k and o Receptors | periaqueductal gray matter (pain) pontine reticular formation median raphe (k) nucleus raphe magnus (k) gigantocellular reticular nucleus spinal cord (dorsal horn) |
| Location of Opioid N/OFQ Receptors | para-aqueduct gray matter median raphe rostral ventral-medial medulla spinal cord (superficial dorsal horn) |
| Opioid u Receptor Antagonists | CTOP naloxone nalorphine |
| Opioid o Receptor Antagonist | natrindole |
| Opioid k Receptor Antagonist | nor BNI |
| Opioid u&k Receptor Antagonists | diprenorphine naltrexone |
| Opioid Receptor Activation MOA | inhibit adenyl cyclase (stops ATP --> cAMP) suppresses voltage-gated Ca2+ currents activates receptor-operated K+ ion channels |
| Opioid Pathophysical Effects | directly inhibit ascending transmission of nociceptive impulses from spinal cord dorsal horn reduce perceived pain, but also improve the ability to emotionally tolerate pain activate |
| Definition of Nociceptive Pain | stimulation of nociceptive neuroreceptors and impulses transmitted over intact neural pathways |
| Definition of Neuropathic Pain | damage or injury to neural structures often involving neural supersensitivity |
| Opioid Side Effects | nausea vomiting drowsiness decreased mentation lower physical activity |
| Effect of Chronic Opioid Administration | u and o receptor internalization (desensitization & tolerance) |
| Butorphanol Tartrate (Morphinan Congener) | used for management of visceral pain frequently in combo with xylazine/detomidine |
| Clinical Applications of Opioids | analgesia for severe pain cough suppression slow GI motility anesthetic/pre-anesthetic agent |
| Naloxone Effects | antagonizes u-opioid receptors and GABA blocks beta-endorphin release elevates arterial blood pressure antagonizes oxymorphone-induced respiratory depression and analgesia reverses fentanyl effects therapeutic management of horse vices vascular shoc |
| Opioid Routes of Administration | parenteral intraspinal (epidural/intrathecal) oral inhalation o |
| Centrally Acting Opioid Antitussive Agents | codeine dextromethorphan levopropoxyphene - l-isomer of dextro nocapine |
| Centrally Acting Non-Opioid Antitussive Agents | caramiphen carbetapentane diphenylhydramine pholcodine benzonatate |
| Basic MOA of Opioids | influences the Limbic System, which influences involuntary responses |
| Three Basic Types of Opioid-Acting Substances | synthetic opioids opiates endogenous peptides (endorphins, enkephalins, dyorphins, endomorphins) |
| What Kind of Pain is Managed More Effectively with Opioids? | continuous dull pain |
| Precursor Polypeptide of Endorphins | pre-pro-opiomelanocortin |
| Precursor Polypeptide of Enkephalins | pre-pro-enkephalin |
| Precursor Polypeptide of Dyorphins | pre-pro-dynorphin |
| Clinical Significance of Morphine Metabolites | have a biological effect indistinguishable from morphine, but are twice as potent |
| Class of Analgesic Drug Used in Conjunction with Opioids to Reduce Necessary Dose of Opioid | barbiturates |