Influence of purinergic modulators on eEPSCs in rat CA3 hippocampal neurons: Contribution of ionotropic ATP receptors |
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Authors: | E Kondratskaya K Nonaka N Akaike |
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Institution: | (1) Kumamoto Health Science University, Kumamoto, Japan |
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Abstract: | ATP is considered to impact on fast synaptic transmission in several regions of the CNS, including the CA1 and CA3 areas of the hippocampus. The existing paradigm suggests that ATP induces synaptic responses in CA3 pyramidal cells, and a fast ATP-mediated component is observed in cultured hippocampal slices mainly under conditions of
a synchronous discharge from multiple presynaptic inputs. We confirmed the existence of a fast ATP-mediated component within
electrically evoked EPSCs (eEPSCs) in CA3 neurons of acute slices of the rat hippocampus using a whole-cell patch-clamp recording mode. In approximately 50% of the
examined cells, eEPSCs were not completely inhibited by co-applied glutamate receptor antagonists, NBQX (50 μM) and D-APV
(25 μM). The residual current was sensitive to ionotropic P2X receptor antagonists, such as suramin (25 μM) and NF023 (2 μM).
Known purinergic receptor modulators, ivermectin (10 μM) and PPADS (10 μM), practically did not affect EPSCs, whereas a nonhydrolyzable
ATP analog, ATPγS (100 μM), slightly decreased the EPSC amplitude. Moreover, ATPγS (100 μM) at a holding potential of −70
mV generated a slow inward current in most recorded neurons, which was insensitive to glutamate receptor antagonists. This
fact is indicative of the ionotropic P2X receptor activation.
Neirofiziologiya/Neurophysiology, Vol. 40, No. 1, pp. 21–29, January–February, 2008. |
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Keywords: | hippocampus CA3 neurons EPSC ATP P2X receptor |
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