ATP reduces voltage-activated K+ current in cultured rat hippocampal neurons |
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Authors: | Ken Nakazawa Kaori Inoue Kazuhide Inoue |
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Institution: | (1) Division of Pharmacology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, 158 Tokyo, Japan |
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Abstract: | Effects of extracellular ATP were investigated in cultured rat hippocampal neurons using whole-cell voltage-clamp techniques.
When a depolarizing step to +10 mV was applied from a holding potential of -60 mV, an outward K+ current was activated. ATP (3 to 300 μM) reduced the K+ current. Among adenosine derivatives, ADP (100 μM) slightly inhibited the K+ current, and AMP or adenosine (100 μM) was ineffective. UTP was as potent as ATP and α,β-methylene ATP was less effective
than ATP. The inhibition by ATP of the K+ current was abolished by inclusion of 2 mM GDPβS in the intracellular solution. The results indicate that ATP inhibits K+ channels in rat hippocampal neurons through UTP-responsive P2-purinoceptors coupled with GTP-binding proteins. |
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Keywords: | ATP hippocampus whole-cell voltageclamp K+ current P2-purinoceptors |
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