Abstract
We previously reported that slow depolarization of substantia gelatinosa neurons is evoked by repetitive stimulation of C-fibers of dorsal root in adult rat spinal cord transverse slices with the dorsal root attached, which was considered to be an event relevant to spinal nociception. In the present study, we investigated the effects of adenosine 5'-triphosphate (ATP) and its analogs on the slow depolarization. ATP (10-100 microM) significantly inhibited the amplitude of slow depolarization in a concentration-dependent manner. The inhibitory effect of ATP was not reversed by suramin, an antagonist for some P2-purinoceptors, and was mimicked by a P2Y selective agonist uridine 5'-triphosphate, but not a P2X selective agonist alpha,beta-methylene ATP. These results suggest that ATP inhibits the slow depolarization of substantia gelatinosa neurons relevant to nociceptive transmission in the spinal dorsal horn, via suramin-insensitive P2Y purinoceptors.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Action Potentials / drug effects*
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Action Potentials / physiology
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Adenosine Triphosphate / analogs & derivatives
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Adenosine Triphosphate / metabolism
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Adenosine Triphosphate / pharmacology*
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Animals
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Dose-Response Relationship, Drug
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Electric Stimulation
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Excitatory Amino Acid Antagonists / pharmacology
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Male
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Neural Inhibition / drug effects*
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Neural Inhibition / physiology
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Nociceptors / cytology
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Nociceptors / drug effects*
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Nociceptors / metabolism
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Pain / metabolism
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Pain / physiopathology
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Presynaptic Terminals / drug effects
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Presynaptic Terminals / metabolism
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Purinergic P2 Receptor Agonists*
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Purinergic P2 Receptor Antagonists
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Rats
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Rats, Sprague-Dawley
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Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
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Receptors, N-Methyl-D-Aspartate / drug effects
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Receptors, Purinergic P2 / metabolism
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Receptors, Purinergic P2Y1
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Spinal Nerve Roots / cytology
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Spinal Nerve Roots / drug effects*
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Spinal Nerve Roots / metabolism
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Substantia Gelatinosa / cytology
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Substantia Gelatinosa / drug effects*
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Substantia Gelatinosa / metabolism
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Suramin / pharmacology
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology
Substances
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Excitatory Amino Acid Antagonists
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P2ry1 protein, rat
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Purinergic P2 Receptor Agonists
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Purinergic P2 Receptor Antagonists
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Receptors, N-Methyl-D-Aspartate
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Receptors, Purinergic P2
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Receptors, Purinergic P2Y1
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Suramin
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Adenosine Triphosphate