Calcium‐Dependent Evoked Release of N[3H]Acetylaspartylglutamate from the Optic Pathway

Guochuan Tsai, Gianluigi Forloni, Michael B. Robinson, Barbara L. Stauch, Joseph T. Coyle

Research output: Contribution to journalArticlepeer-review

67 Scopus citations


Abstract: N‐Acetylaspartylglutamate (NAAG) is a neuropeptide localized to several putative glutamatergic neuronal systems, including the rodent optic pathway. To determine whether the peptide is released by depolarization, the superior colliculus of the rat was perfused with 2 μCi of [3H]NAAG, then with Krebs‐bicarbonate buffer for 1 h, using a microdialysis system. Subsequently, 10‐min fractions were collected and analyzed by HPLC for [3H]NAAG. Addition of 100 μM veratridine resulted in a several‐fold increase in the evoked release of [3H]NAAG that was virtually abolished by coperfusion with Ca2+‐free Krebs buffer containing 1 mM EGTA. When [3H]glutamate was used as the precursor, veratridine depolarization resulted in only an 80% increase in the release of [3H]NAAG. Prior enucleation of the right eye reduced the spontaneous release of [3H]NAAG by 50%, and the veratridine‐evoked release by greater than 85%, from the left superior colliculus. These results suggest that NAAG is released upon depolarization and may serve as a neurotransmitter/neuromodulator in the optic tract.

Original languageEnglish (US)
Pages (from-to)1956-1959
Number of pages4
JournalJournal of Neurochemistry
Issue number6
StatePublished - Dec 1988


  • Evoked release
  • Gluta‐mate
  • N‐Acetylaspartylglutamate
  • Optic tract
  • Peptidase
  • Superior colliculus

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience


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