Short-term depression at the reciprocal synapses between a retinal bipolar cell terminal and amacrine cells

Geng Lin Li, Jozsef Vigh, Henrique Von Gersdorff

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Visual adaptation is thought to occur partly at retinal synapses that are subject to plastic changes. However, the locus and properties of this plasticity are not well known. Here, we studied short-term plasticity at the reciprocal synapse between bipolar cell terminals and amacrine cells in goldfish retinal slices. Depolarization of a single bipolar cell terminal for 100 ms triggers the release of glutamate onto amacrine cell processes, which in turn leads to GABAergic feedback from amacrine cells onto the same terminal. We find that this release of GABA undergoes paired-pulse depression (PPD) that recovers in <1 min (single exponential time constant, τ ≅ 12 s). This disynaptic PPD is independent of mGluR-mediated plasticity and depletion of glutamatergic synaptic vesicle pools, because exocytosis assayed via capacitance jumps (ΔCm) recovered completely after 10 s (τ ≅ 2 s). Fast application of GABA (10mΜ) onto outside-out patches excised from bipolar cell terminals showed that the recovery of GABAA receptors from desensitization depends on the duration of the application [fast recovery (<2 s) for short applications; slow (τ ≅ 12 s) for prolonged applications]. We thus blocked GABAA receptors and retested the GABAergic response mediated by nondesensitizing GABAC receptors to two rapid glutamate puffs onto the bipolar cell terminal. These responses consistently displayed PPD. Furthermore, blocking AMPA-receptor desensitization with cyclothiazide, or evoking GABA release with NMDA receptors, did not reduce PPD. We thus suggest that depletion of synaptic vesicle pools in GABAergic amacrine cells is a major contributor to PPD.

Original languageEnglish (US)
Pages (from-to)7377-7385
Number of pages9
JournalJournal of Neuroscience
Volume27
Issue number28
DOIs
StatePublished - Jul 11 2007

Keywords

  • Adaptation
  • Amacrine cells
  • Bipolar cell terminals
  • Inner plexiform layer
  • Membrane capacitance
  • Microcircuits
  • Paired-pulse depression
  • Retina
  • Short-term plasticity

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Short-term depression at the reciprocal synapses between a retinal bipolar cell terminal and amacrine cells'. Together they form a unique fingerprint.

  • Cite this