Abstract
We carried out experiments using a microdialysis method to determine whether activation of 5-HT(3) receptors increases the concentration of GABA in the dorsal horn of the spinal cord. Intrathecal perfusion of a selective 5-HT(3) receptor agonist, 1-phenylbiguanide (0.3, 1.0, and 3.0 mM) dose-dependently, increased GABA concentration, while concentrations of glutamate and glycine were not changed. The concentration of aspartate was increased only by 3.0 mM of 1-phenylbiguanide. Our results have provided direct evidence that activation of 5-HT(3) receptors evokes GABA release in the spinal dorsal horn, possibly producing analgesia.
MeSH terms
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Animals
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Aspartic Acid / metabolism
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Biguanides / pharmacology
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Dose-Response Relationship, Drug
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Glutamic Acid / metabolism
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Glycine / metabolism
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Male
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Microdialysis / methods
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Rats
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Rats, Sprague-Dawley
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Receptors, Serotonin / metabolism*
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Receptors, Serotonin, 5-HT3
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Serotonin Receptor Agonists / pharmacology*
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Spinal Cord / anatomy & histology
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Spinal Cord / chemistry
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Spinal Cord / drug effects
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Spinal Cord / metabolism*
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Time Factors
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gamma-Aminobutyric Acid / metabolism*
Substances
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Biguanides
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Receptors, Serotonin
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Receptors, Serotonin, 5-HT3
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Serotonin Receptor Agonists
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Aspartic Acid
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Glutamic Acid
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gamma-Aminobutyric Acid
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Glycine
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phenyl biguanide