title: Appearance of fast astrocytic component in voltage-sensitive dye imaging of neural activity.
abstract: BACKGROUND
  Voltage-sensitive dye (VSD) imaging and intrinsic optical signals (IOS) are widely used methods for monitoring spatiotemporal neural activity in extensive networks. In spite of that, identification of their major cellular and molecular components has not been concluded so far.
  
  
  RESULTS
  We addressed these issues by imaging spatiotemporal spreading of IOS and VSD transients initiated by Schaffer collateral stimulation in rat hippocampal slices with temporal resolution comparable to standard field potential recordings using a 464-element photodiode array. By exploring the potential neuronal and astroglial molecular players in VSD and IOS generation, we identified multiple astrocytic mechanisms that significantly contribute to the VSD signal, in addition to the expected neuronal targets. Glutamate clearance through the astroglial glutamate transporter EAAT2 has been shown to be a significant player in VSD generation within a very short (<5 ms) time-scale, indicating that astrocytes do contribute to the development of spatiotemporal VSD transients previously thought to be essentially neuronal. In addition, non-specific anion channels, astroglial K(+) clearance through Kir4.1 channel and astroglial Na(+)/K(+) ATPase also contribute to IOS and VSD transients.
  
  
  CONCLUSIONS
  VSD imaging cannot be considered as a spatially extended field potential measurement with predominantly neuronal origin, instead it also reflects a fast communication between neurons and astrocytes.
authors.affiliation: Group of Functional Pharmacology, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, H-1117, Budapest, Hungary. pal.ildiko@ttk.mta.hu.
authors.forename: Ildikó
authors.initials: I
authors.lastname: Pál
authors.affiliation: Group of Functional Pharmacology, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, H-1117, Budapest, Hungary. kardos.julianna@ttk.mta.hu.
authors.forename: Julianna
authors.initials: J
authors.lastname: Kardos
authors.affiliation: MTA-ELTE-NAP B Laboratory of Molecular and Systems Neurobiology, H-1117, Budapest, Hungary. dobolyi.arpad@med.semmelweis-univ.hu.|Department of Anatomy, Human Brain Tissue Bank, Semmelweis University, H-1450, Budapest, Hungary. dobolyi.arpad@med.semmelweis-univ.hu.
authors.forename: Árpád
authors.initials: Á
authors.lastname: Dobolyi
authors.affiliation: Group of Functional Pharmacology, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, H-1117, Budapest, Hungary. heja.laszlo@ttk.mta.hu.
authors.forename: László
authors.initials: L
authors.lastname: Héja
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000378:metabolism; D000200:Action Potentials; D000818:Animals; D000838:Anions; D001253:Astrocytes / Q000378:metabolism*; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism; D006706:Homeostasis; D008297:Male; D008954:Models, Biological; D009457:Neuroglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D055620:Optical Phenomena; D017208:Rats, Wistar; D064506:Solute Carrier Family 12, Member 2 / Q000378:metabolism; D056969:Voltage-Sensitive Dye Imaging / Q000379:methods*
chemical_list: D000838:Anions; D027342:Excitatory Amino Acid Transporter 2; C578879:Slc12a2 protein, rat; C493395:Slc1a2 protein, rat; D064506:Solute Carrier Family 12, Member 2; D018698:Glutamic Acid; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid