Glutamate spillover mediates excitatory transmission in the rat olfactory bulb

Authors
Citation
Js. Isaacson, Glutamate spillover mediates excitatory transmission in the rat olfactory bulb, NEURON, 23(2), 1999, pp. 377-384
Citations number
46
Categorie Soggetti
Neurosciences & Behavoir
Journal title
NEURON
ISSN journal
08966273 → ACNP
Volume
23
Issue
2
Year of publication
1999
Pages
377 - 384
Database
ISI
SICI code
0896-6273(199906)23:2<377:GSMETI>2.0.ZU;2-6
Abstract
In the CNS, glutamate typically mediates excitatory transmission via local actions at synaptic contacts. In the olfactory bulb, mitral cell dendrites release glutamate at synapses formed only onto the dendrites of inhibitory granule cells, Here, I show excitatory transmission mediated solely by tran smitter spillover between mitral cells in olfactory bulb slices. Dendritic glutamate release from individual mitral cells causes self-excitation via l ocal activation of N-methyl-D-aspartate (NMDA) receptors. Paired recordings reveal that glutamate release from one cell generates NMDA receptor-mediat ed responses in neighboring mitral cells that are enhanced by blockade of g lutamate uptake. Furthermore, spillover generates spontaneous NMDA receptor -mediated population responses. This simultaneous activation of neighboring mitral cells by a diffuse action of glutamate provides a mechanism for syn chronizing olfactory principal cells.