Mechanism of action of rab3A in mossy fiber LTP

György Lonart, Roger Janz, Kenneth M. Johnson, Thomas C. Südhof

Research output: Contribution to journalArticle

96 Scopus citations

Abstract

In mossy fiber synapses of the hippocampal CA3 region, LTP is induced by cAMP and requires the synaptic vesicle protein rab3A. In contrast, CA1- region synapses do not exhibit this type of LTP. We now show that cAMP enhances glutamate release from CA3 but not CA1 synaptosomes by (1) increasing the readily releasable pool as tested by hypertonic sucrose; (2) potentiating release evoked by KCl depolarization, which opens voltage-gated Ca2+ channels; and (3) by enhancing Ca2+ action on the secretory apparatus as monitored by the Ca2+-ionophore ionomycin. In rab3A-deficient synaptosomes, forskolin still enhances KCl-and sucrose-induced glutamate release but not ionomycin-induced release. Our results show that cAMP has multiple actions in mossy fiber synapses, of which only the direct activation of the secretory apparatus requires rab3A and functions in mfLTP.

Original languageEnglish (US)
Pages (from-to)1141-1150
Number of pages10
JournalNeuron
Volume21
Issue number5
DOIs
StatePublished - Nov 1998

ASJC Scopus subject areas

  • Neuroscience(all)

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    Lonart, G., Janz, R., Johnson, K. M., & Südhof, T. C. (1998). Mechanism of action of rab3A in mossy fiber LTP. Neuron, 21(5), 1141-1150. https://doi.org/10.1016/S0896-6273(00)80631-5