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ludc web

João Vieira

Doctoral student

ludc web

FAD-Linked Autofluorescence and Chemically-Evoked Zinc Changes at Hippocampal Mossy Fiber-CA3 Synapses

Author

  • Fatima M.C. Bastos
  • Carlos M. Matias
  • Ines O. Lopes
  • João P. Vieira
  • Rosa M. Santos
  • Luis M. Rosario
  • Rosa M. Quinta-Ferreira
  • Maria Emília Quinta-Ferreira

Editor

  • Prof. Xinhua Zhang

Summary, in English

Glutamatergic vesicles in hippocampal mossy fiber presynaptic boutons release zinc, which plays a modulatory role in synaptic activity and LTP. In this work, a fluorescence microscopy technique and the fluorescent probe for cytosolic zinc, Newport Green (NG), were applied, in a combined study of autofluorescence and zinc changes at the hippocampal mossy fiber-CA3 synaptic system. In particular, the dynamics of flavoprotein (FAD) autofluorescence signals, was compared to that of postsynaptic zinc signals, elicited both by high K+ (20 mM) and by tetraethylammonium (TEA, 25 mM). The real zinc signals were obtained subtracting autofluorescence values, from corresponding total NG-fluorescence data. Both autofluorescence and zinc-related fluorescence were raised by high K+. In contrast, the same signals were reduced during TEA exposure. It is suggested that the initial outburst of TEA-evoked zinc release might activate ATP-sensitive K+ (KATP) channels, as part of a safeguard mechanism against excessive glutamatergic action. This would cause sustained inhibition of zinc signals and a more reduced mitochondrial state. In favor of the “KATP channel hypothesis”, the KATP channel blocker tolbutamide (250 μM) nearly suppressed the TEA-evoked fluorescence changes. It is concluded that recording autofluorescence from brain slices is essential for the accurate assessment of zinc signals and actions.

Publishing year

2021-11-03

Language

English

Publication/Series

Hippocampus - New Advances [Working Title]

Document type

Book chapter

Publisher

IntechOpen

Topic

  • Neurosciences
  • Neurology

Status

Published