Enhancement of excitatory synaptic transmission in spiny neurons after transient forebrain ischemia

Yuchun Zhang, Ping Deng, Yan Li, Zao C. Xu

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Spiny neurons in the neostriatum are highly vulnerable to ischemia. Enhancement of excitatory synaptic transmissions has been implicated in ischemia-induced excitotoxic neuronal death. Here we report that evoked excitatory postsynaptic currents in spiny neurons were potentiated after transient forebrain ischemia. The ischemia-induced potentiation in synaptic efficacy was associated with an enhancement of presynaptic release as demonstrated by an increase in the frequency of miniature excitatory postsynaptic currents (mEPSCs) and a decrease in the paired-pulse ratio. The amplitude of inward currents evoked by exogenous application of glutamate did not show significant changes after ischemia, suggesting that postsynaptic mechanism is not involved. The ischemia-induced increase in mEPSCs frequency was not affected by blockade of voltage-gated calcium channels, but it was eliminated in the absence of extracellular calcium. Bath application of ATP P2X receptor antagonist pyridoxal-phosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS) significantly reduced mEPSC frequency in ischemic neurons but had no effects on the control ones. Furthermore, the inhibitory effect of PPADS on ischemic neurons was abolished in Ca2+-free external solution. These results indicate that excitatory synaptic transmissions in spiny neurons are potentiated after ischemia via presynaptic mechanisms. Activation of P2X receptors and the consequent Ca2+ influx might contribute to the ischemiainduced facilitation of glutamate release.

Original languageEnglish
Pages (from-to)1537-1544
Number of pages8
JournalJournal of Neurophysiology
Volume95
Issue number3
DOIs
StatePublished - Mar 2006

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Prosencephalon
Synaptic Transmission
Ischemia
Neurons
Excitatory Postsynaptic Potentials
Pyridoxal Phosphate
Glutamic Acid
Purinergic P2 Receptors
Neostriatum
Acids
Calcium Channels
Baths
Calcium

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

Cite this

Enhancement of excitatory synaptic transmission in spiny neurons after transient forebrain ischemia. / Zhang, Yuchun; Deng, Ping; Li, Yan; Xu, Zao C.

In: Journal of Neurophysiology, Vol. 95, No. 3, 03.2006, p. 1537-1544.

Research output: Contribution to journalArticle

Zhang, Yuchun ; Deng, Ping ; Li, Yan ; Xu, Zao C. / Enhancement of excitatory synaptic transmission in spiny neurons after transient forebrain ischemia. In: Journal of Neurophysiology. 2006 ; Vol. 95, No. 3. pp. 1537-1544.
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