Coupling of Neural Activity to Blood Flow in Olfactory Glomeruli Is Mediated by Astrocytic Pathways

Gabor C. Petzold, Dinu F. Albeanu, Tomokazu F. Sato, Venkatesh N. Murthy

Research output: Contribution to journalArticlepeer-review

200 Scopus citations


Functional neuroimaging uses activity-dependent changes in cerebral blood flow to map brain activity, but the contributions of presynaptic and postsynaptic activity are incompletely understood, as are the underlying cellular pathways. Using intravital multiphoton microscopy, we measured presynaptic activity, postsynaptic neuronal and astrocytic calcium responses, and erythrocyte velocity and flux in olfactory glomeruli during odor stimulation in mice. Odor-evoked functional hyperemia in glomerular capillaries was highly correlated with glutamate release, but did not require local postsynaptic activity. Odor stimulation induced calcium transients in astrocyte endfeet and an associated dilation of upstream arterioles. Calcium elevations in astrocytes and functional hyperemia depended on astrocytic metabotropic glutamate receptor 5 and cyclooxygenase activation. Astrocytic glutamate transporters also contributed to functional hyperemia through mechanisms independent of calcium rises and cyclooxygenase activation. These local pathways initiated by glutamate account for a large part of the coupling between synaptic activity and functional hyperemia in the olfactory bulb.

Original languageEnglish (US)
Pages (from-to)897-910
Number of pages14
Issue number6
StatePublished - Jun 26 2008
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by funds from Harvard University (V.N.M.), Pew Scholars Program (V.N.M.), German Science Foundation DFG (G.C.P., Pe 1193/1-1), and Marie Curie Fellowship Program of the European Union (G.C.P.).




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