In vivo imaging of neuronal activity by targeted expression of a genetically encoded probe in the mouse.
Genetically encoded probes show great promise in permitting functional imaging of specified neuronal populations in the intact nervous system, yet their in vivo application has been limited. Here, we have targeted expression of synapto-pHluorin, a pH-sensitive protein that reports synaptic vesicle fusion, to olfactory sensory neurons in mouse. Synapto-pHluorin selectively labeled presynaptic terminals of sensory neurons in glomeruli of the olfactory bulb. Odorant stimulation evoked large-amplitude fluorescence increases that were localized to individual glomeruli in vivo, correlated with presynaptic calcium influx, graded with stimulus intensity, and stable over a period of days. Spatial patterns of odorant-activated glomeruli were distributed and did not change systematically with increasing carbon chain length, in contrast to the finely organized chemotopy that has been reported using other imaging methods. Targeted expression of synapto-pHluorin in mouse will permit the analysis of previously inaccessible neuronal populations and chronic imaging from genetically identified neurons in vivo.
Bozza
Thomas
T
The Rockefeller University, New York, NY 10021, USA.
McGann
John P
JP
Mombaerts
Peter
P
Wachowiak
Matt
M
D000447:Aldehydes / Q000494:pharmacology; D000818:Animals; D001931:Brain Mapping; D003001:Cloning, Molecular / Q000379:methods; D003911:Dextrans / Q000378:metabolism; D003952:Diagnostic Imaging / Q000379:methods; D004305:Dose-Response Relationship, Drug; D005071:Evoked Potentials / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology*; D018390:Gene Targeting / Q000379:methods*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009475:Neurons, Afferent / Q000502:physiology*; D009812:Odorants; D009830:Olfactory Bulb / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D051842:Olfactory Marker Protein; D009831:Olfactory Mucosa; D021381:Protein Transport; D013268:Stimulation, Chemical; D013997:Time Factors
D000447:Aldehydes; D003911:Dextrans; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D051842:Olfactory Marker Protein; C497598:Omp protein, mouse; C485506:synapto-pHluorin protein, mouse; D049452:Green Fluorescent Proteins; C010463:n-hexanal; C018475:butyraldehyde