P2X receptor subtype-specific modulation of excitatory and inhibitory synaptic inputs in the rat brainstem |
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Authors: | Tomokazu Watano Jennifer A Calvert Catherine Vial Ian D Forsythe Richard J Evans |
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Institution: | Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, University Road, Leicester, LE1 9HN, UK |
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Abstract: | The role of P2 receptors in synaptic transmission to the rat medial nucleus of the trapezoid body (MNTB) was studied in an in vitro brain slice preparation. Whole-cell patch recordings were made and spontaneous synaptic responses studied under voltage clamp during application of P2X receptor agonists. ATPγS (100 μ m ) had no effect on holding current, but facilitated spontaneous excitatory postsynaptic current (sEPSC) frequency in 41% of recordings and facilitated spontaneous inhibitory postsynaptic currents (sIPSCs) in 20% of recordings. These were blocked by the P2 receptor antagonist suramin (100 μ m ). α,β-meATP also facilitated sEPSC and sIPSC frequency, while l -β,γ-meATP facilitated only sIPSCs. The sEPSC facilitation by ATPγS was blocked by TTX (but did not block facilitation of sIPSCs). sEPSC facilitation was blocked by PPADS (30 μ m ) and the selective P2X3 receptor antagonist A-317491 (3 μ m ), suggesting that modulation of sEPSCs involves P2X3 receptor subunits. α,β-meATP-facilitated sIPSCs were also recorded in wild-type mouse MNTB neurones, but were absent in the MNTB from P2X1 receptor-deficient mice demonstrating a functional role for P2X1 receptors in the CNS. |
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