Abstract
Beta-endorphin (4 micrograms) injected i.v.t. induced the release of immunoreactive [Met5]enkephalin and sulfated cholecystokinin octapeptide (CCK-8s) from the spinal cord in the pentobarbital-anesthetized rat. The inhibition of the tail-flick response induced by beta-endorphin given i.v.t. was antagonized by i.t. injection of CCK-8s and potentiated by i.t. administration of the antibody to CCK-8s. The findings give support to the hypothesis that endogenous CCK-8s in the spinal cord may play a negative feedback role in modulating beta-endorphin-induced antinociception.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Anesthesia
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Animals
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Cholecystokinin / immunology
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Cholecystokinin / metabolism*
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Cholecystokinin / pharmacology
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Enkephalin, Methionine / immunology
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Enkephalin, Methionine / metabolism*
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Injections, Intraventricular
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Injections, Spinal
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Male
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Pain Measurement
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Pentobarbital
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Rats
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Rats, Sprague-Dawley
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Reaction Time / drug effects
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Spinal Cord / drug effects
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Spinal Cord / metabolism*
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beta-Endorphin / administration & dosage
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beta-Endorphin / pharmacology*
Substances
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Enkephalin, Methionine
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beta-Endorphin
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Cholecystokinin
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Pentobarbital