Abstract
Opiates hyperpolarize locus coeruleus neurons by simultaneously opening K+ channels and turning off a resting Na(+)-dependent inward current. Intracellularly applied QX-314 reduced the opiate current to approximately 40% of the control and the residual current did not reverse near EK, suggesting lack of a significant K+ component. Replacement of Na+ virtually abolished the residual opiate response. Thus, QX-314 blocks the K+ but not the Na(+)-dependent component of the opiate-induced outward current in LC neurons.
MeSH terms
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Anesthetics, Local / pharmacology*
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Animals
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Enkephalin, Methionine / pharmacology
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Enkephalins / pharmacology
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In Vitro Techniques
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Lidocaine / analogs & derivatives*
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Lidocaine / pharmacology
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Locus Coeruleus / cytology
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Locus Coeruleus / drug effects
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Locus Coeruleus / metabolism*
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Narcotic Antagonists*
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Neural Conduction / drug effects
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Neurons / drug effects
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Neurons / metabolism*
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Potassium Channels / drug effects*
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Rats
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Receptors, Opioid / drug effects
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Sodium Channels / drug effects*
Substances
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Anesthetics, Local
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Enkephalins
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Narcotic Antagonists
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Potassium Channels
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Receptors, Opioid
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Sodium Channels
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QX-314
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Enkephalin, Methionine
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Lidocaine