Pharm Exam 1.2
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Questions and Answers

Which type of ion channels do anesthetics primarily target?

  • Sodium, potassium, HCN, and GABA-activated chloride channels (correct)
  • Sodium, potassium, calcium, and chloride channels
  • Calcium, chloride, HCN, and GABA-activated chloride channels
  • Potassium, calcium, HCN, and GABA-activated chloride channels

    • What effect do anesthetics have on nerves?

  • Stabilization
  • No effect on polarization
  • Depolarization
  • Hyperpolarization (correct)

    • Which receptors do volatile anesthetics, propofol, barbiturates, and neurosteroids potentiate?

  • Nicotinic acetylcholine receptors
  • GABA receptors
  • Glycine receptors (correct)
  • NMDA receptors

    • What is the primary site of action for general anesthetics?

    <p>Synapse</p> Signup and view all the answers

    Which rule explains the relationship between anesthetic potency and chain length?

    <p>Meyer-Overton Rule</p> Signup and view all the answers

    What is the main reason for enantiomers exhibiting different anesthetic potency?

    <p>Different binding to specific lipophilic amino acids</p> Signup and view all the answers

    What are the exceptions to the Meyer-Overton Rule explained by?

    <p>Anesthetic binding of specific lipophilic amino acids</p> Signup and view all the answers

    Which ligand-gated ion channels are affected by anesthetics?

    <p>GABA-activated and glycine-activated channels</p> Signup and view all the answers

    What is the effect of different anesthetics on subtypes of the GABA receptor?

    <p>Potentiation, direct gating, or inhibition</p> Signup and view all the answers

    Which receptors are affected by etomidate and ketamine?

    <p>NMDA receptors</p> Signup and view all the answers

    Where can graphic summaries on the topic be found?

    <p>Barash Clinical Anesthesia, Flood Stoelting’s Pharmacology and Physiology in Anesthetic Practice, and Evers Anesthetic Pharmacology.</p> Signup and view all the answers

    Which component is not part of general anesthesia?

    <p>Long-term memory impairment</p> Signup and view all the answers

    What is the primary site of action of dexmedetomidine?

    <p>Locus coeruleus</p> Signup and view all the answers

    Where is immobility thought to be primarily mediated?

    <p>Spinal cord level</p> Signup and view all the answers

    What is now thought to be the primary target for anesthetic action?

    <p>Protein</p> Signup and view all the answers

    Which component is thought to be primarily mediated at the spinal cord level?

    <p>Immobility</p> Signup and view all the answers

    What is the primary source of cholinergic input to the cerebral cortex?

    <p>Nucleus basalis of Meynert</p> Signup and view all the answers

    Which nucleus is the primary site of action of dexmedetomidine?

    <p>Locus coeruleus</p> Signup and view all the answers

    What is now thought to be the primary target for anesthetic action?

    <p>Protein</p> Signup and view all the answers

    Which of the following components are NOT part of general anesthesia?

    <p>Euphoria</p> Signup and view all the answers

    What is the primary site of action for immobility during anesthesia?

    <p>Spinal cord</p> Signup and view all the answers

    Which of the following anesthetics exhibits a biphasic dose response for analgesia?

    <p>Ketamine</p> Signup and view all the answers

    Which brain region stabilizes the sleep-wake switch?

    <p>Tuberomammillary nucleus (TMN)</p> Signup and view all the answers

    What is the primary mechanism for preventing awareness during anesthesia monitoring?

    <p>$\gamma$-aminobutyric acid (GABA)ergic inhibition</p> Signup and view all the answers

    What is the effect of general anesthesia on long-term memory?

    <p>It ablates conscious memory (explicit) and unconscious memory (implicit)</p> Signup and view all the answers

    Which of the following sites are NOT considered anesthetic targets?

    <p>Endoplasmic reticulum</p> Signup and view all the answers

    What do volatile anesthetics primarily target for their effect on autonomic homeostatic mechanisms?

    <p>Hypothalamus</p> Signup and view all the answers

    Which nucleus likely interferes with thalamic input to the cerebral cortex during unconsciousness induced by general anesthesia?

    <p>Ventrolateral preoptic nucleus (VLPO)</p> Signup and view all the answers

    What is the effect of general anesthesia on new memories?

    <p>It prevents the formation of new memories.</p> Signup and view all the answers

    Which rule initially suggested a single mechanism of anesthesia but faced challenges due to the dissimilar effects of halogenated anesthetics with similar structures and octanol:water partition coefficients?

    <p>Meyer-Overton Rule</p> Signup and view all the answers

    Which of the following is not a component of general anesthesia?

    <p>Hypothermia</p> Signup and view all the answers

    What is the primary site of action for immobility during anesthesia?

    <p>Spinal cord</p> Signup and view all the answers

    Which monitoring method is not more successful in preventing awareness during anesthesia than a protocol using MAC?

    <p>Blood pressure monitoring</p> Signup and view all the answers

    What exhibits a biphasic dose response for analgesia during anesthesia?

    <p>Volatile anesthetics</p> Signup and view all the answers

    Which of the following structures likely interferes with thalamic input to the cerebral cortex during unconsciousness?

    <p>$\text{VLPO}$ (ventrolateral preoptic nucleus)</p> Signup and view all the answers

    What mechanism primarily mediates immobility during anesthesia?

    <p>GABAergic inhibition</p> Signup and view all the answers

    Which of the following components does general anesthesia generally prevent?

    <p>Formation of new memories</p> Signup and view all the answers

    Which rule initially suggested a single mechanism of anesthesia?

    <p>Meyer-Overton Rule</p> Signup and view all the answers

    What primarily impairs autonomic homeostatic mechanisms during general anesthesia?

    <p>Hypothalamus</p> Signup and view all the answers

    What is involved in long-term memory formation during general anesthesia?

    <p>Hippocampus and amygdala</p> Signup and view all the answers

    Which receptors do volatile anesthetics potentiate?

    <p>GABA receptors</p> Signup and view all the answers

    Which of the following is NOT a component of general anesthesia?

    <p>Hypothermia</p> Signup and view all the answers

    What is the primary effect of general anesthesia on memory formation?

    <p>Prevents formation of new memories</p> Signup and view all the answers

    Which monitoring method is NOT significantly more successful in preventing awareness during anesthesia?

    <p>Blood pressure monitoring</p> Signup and view all the answers

    What is the primary mediator of immobility during anesthesia?

    <p>Spinal cord level</p> Signup and view all the answers

    Which of the following is NOT a likely anesthetic target for unconsciousness?

    <p>$\beta$-amyloid plaques</p> Signup and view all the answers

    Which mechanism contributes to analgesia under volatile anesthetics?

    <p>Activation of opioid receptors</p> Signup and view all the answers

    What is the primary site of action for mediating autonomic homeostatic mechanisms during anesthesia?

    <p>Hypothalamus</p> Signup and view all the answers

    What do volatile anesthetics exhibit in terms of dose response for analgesia?

    <p>Biphasic response</p> Signup and view all the answers

    Which area activates various brain regions and stabilizes the sleep-wake switch?

    <p>Perifornical area</p> Signup and view all the answers

    What is the primary effect of general anesthesia on unconscious memory (implicit)?

    <p>Erases all unconscious memories</p> Signup and view all the answers

    What do anesthetics primarily affect at the spinal cord level to induce immobility?

    <p>Descending motor pathways</p> Signup and view all the answers

    Which rule initially suggested a single mechanism of anesthesia but faced challenges due to dissimilar effects of halogenated anesthetics with similar structures?

    <p>Meyer-Overton rule</p> Signup and view all the answers

    Study Notes

    Electrophysiological Effects of Anesthetics

    • Anesthetic potency increases with chain length but has a cutoff effect.
    • Enantiomers exhibit different anesthetic potency despite identical octanol:water partition coefficient.
    • Meyer-Overton Rule and its exceptions are explained by anesthetic binding of specific lipophilic amino acids.
    • Anesthetics hyperpolarize nerves and this effect correlates with anesthetic potency.
    • General anesthetics primarily act at the synapse, inhibiting glutamate release and potentiating GABA.
    • Anesthetics target ion channels including Na+, K+, HCN, and GABA-activated chloride channels.
    • Anesthetics also affect ligand-gated ion channels such as glutamate-activated NMDA and GABA-activated channels.
    • Different anesthetics act at different subtypes of the GABA receptor, leading to potentiation, direct gating, or inhibition.
    • Anesthetics affect other ligand-gated ion channels like nicotinic acetylcholine, 5-HT3, and glycine receptors.
    • Volatile anesthetics, propofol, barbiturates, and neurosteroids potentiate glycine receptors but not etomidate or ketamine.
    • There are graphic summaries available on the topic.
    • Sources include Barash Clinical Anesthesia, Flood Stoelting’s Pharmacology and Physiology in Anesthetic Practice, and Evers Anesthetic Pharmacology.

    Understanding General Anesthesia and Anesthetic Targets

    • General anesthesia is a reversible depression of the CNS, causing loss of response to external stimuli and consists of components such as unconsciousness, amnesia, analgesia, immobility, and attenuation of the autonomic response.
    • Unconsciousness involves impairment of connectivity and integration between cortical structures, similar to NREM sleep, and likely interferes with thalamic input to the cerebral cortex and other subcortical structures.
    • The sleep/wake cycle involves the interaction between the tuberomammillary nucleus (TMN) and ventrolateral preoptic nucleus (VLPO), with orexin from the perifornical area activating various brain regions and stabilizing the sleep-wake switch.
    • Likely anesthetic targets for unconsciousness include the cerebral cortex, thalamus, TMN, VLPO, perifornical area, and locus coeruleus, with GABAergic inhibition and cholinergic stimulation affecting these areas.
    • Anesthesia generally prevents the formation of new memories, but leaves previous memories intact, with different mechanisms involved in short-term and long-term memory.
    • Long-term memory formation involves critical steps in the hippocampus and amygdala, and the conversion of short-term to long-term memory requires anatomical changes in the synapse and takes time.
    • General anesthesia ablates conscious memory (explicit) and unconscious memory (implicit), with varying incidences of awareness with recall observed in different patient groups.
    • Awareness monitoring during anesthesia is based on processed EEG and BIS (Bispectral Index), but studies have shown that the BIS monitor is not more successful in preventing awareness than a protocol using MAC.
    • Volatile anesthetics exhibit a biphasic dose response for analgesia, while opioids, non-opioids, α2 agonists, neostigmine, ketamine, barbiturates, nitrous oxide, xenon, and adenosine also contribute to analgesia through different mechanisms.
    • Immobility during anesthesia is primarily mediated at the spinal cord level, affecting afferent pathways, efferent pathways, and reflex spinal arcs, with different anesthetics working through different mechanisms.
    • Multiple anesthetics impair autonomic homeostatic mechanisms, including those related to respiratory, cardiac, and temperature regulation, mediated by the hypothalamus.
    • Anesthetic targets sites include the lipid, protein, neuron, synapse, presynaptic, postsynaptic, and ion channels, with the Meyer-Overton Rule initially suggesting a single mechanism of anesthesia, but facing challenges due to the dissimilar effects of halogenated anesthetics with similar structures and octanol:water partition coefficients.

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    MECHANISMS OF ANESTHESIA AND CONSCIOUSNESS-STUDENT.pptx

    Description

    Test your knowledge about the components of general anesthesia and the mechanisms of consciousness. Learn about unconsciousness, amnesia, analgesia, immobility, and the effects of anesthetics on the sleep-wake cycle.

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