title: Sulforhodamine 101 as a specific marker of astroglia in the neocortex in vivo.
abstract: Glial cells have been identified as key signaling components in the brain; however, methods to investigate their structure and function in vivo have been lacking. Here, we describe a new, highly selective approach for labeling astrocytes in intact rodent neocortex that allows in vivo imaging using two-photon microscopy. The red fluorescent dye sulforhodamine 101 (SR101) was specifically taken up by protoplasmic astrocytes after brief exposure to the brain surface. Specificity was confirmed by immunohistochemistry. In addition, SR101 labeled enhanced green fluorescent protein (EGFP)-expressing astrocytes but not microglial cells in transgenic mice. We used SR101 labeling to quantify morphological characteristics of astrocytes and to visualize their close association with the cortical microvasculature. Furthermore, by combining this method with calcium indicator loading of cell populations, we demonstrated distinct calcium dynamics in astroglial and neuronal networks. We expect SR101 staining to become a principal tool for investigating astroglia in vivo.
authors.affiliation: Abteilung Zellphysiologie, Max-Planck Institut für medizinische Forschung, Jahnstr. 29, 69120 Heidelberg, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Nimmerjahn
authors.forename: Frank
authors.initials: F
authors.lastname: Kirchhoff
authors.forename: Jason N D
authors.initials: JN
authors.lastname: Kerr
authors.forename: Fritjof
authors.initials: F
authors.lastname: Helmchen
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology* / Q000502:physiology*; D015415:Biomarkers / Q000032:analysis; D002118:Calcium; D020013:Calcium Signaling / Q000502:physiology*; D005456:Fluorescent Dyes; D017629:Gap Junctions / Q000502:physiology / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D019579:Neocortex / Q000166:cytology* / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012235:Rhodamines; D013194:Staining and Labeling / Q000379:methods
chemical_list: D015415:Biomarkers; D005456:Fluorescent Dyes; D012235:Rhodamines; C050829:sulforhodamine 101; D002118:Calcium