P2X receptor subtype-specific modulation of excitatory and inhibitory synaptic inputs in the rat brainstem
- Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, University Road, Leicester, LE1 9HN, UK
- Corresponding author R. J. Evans: Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, University Road, Leicester, LE1 9HN, UK. Email: RJE6{at}le.ac.uk
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 μm) 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 μm). 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 μm) and the selective P2X3 receptor antagonist A-317491 (3 μm), 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.
Footnotes
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- Accepted June 4, 2004.
- Received April 21, 2004.
- Revision received May 31, 2004.
- The Physiological society 2004
