title: Prolonged Intracellular Na+ Dynamics Govern Electrical Activity in Accessory Olfactory Bulb Mitral Cells.
abstract: Persistent activity has been reported in many brain areas and is hypothesized to mediate working memory and emotional brain states and to rely upon network or biophysical feedback. Here, we demonstrate a novel mechanism by which persistent neuronal activity can be generated without feedback, relying instead on the slow removal of Na+ from neurons following bursts of activity. We show that mitral cells in the accessory olfactory bulb (AOB), which plays a major role in mammalian social behavior, may respond to a brief sensory stimulation with persistent firing. By combining electrical recordings, Ca2+ and Na+ imaging, and realistic computational modeling, we explored the mechanisms underlying the persistent activity in AOB mitral cells. We found that the exceptionally slow inward current that underlies this activity is governed by prolonged dynamics of intracellular Na+ ([Na+]i), which affects neuronal electrical activity via several pathways. Specifically, elevated dendritic [Na+]i reverses the Na+-Ca2+ exchanger activity, thus modifying the [Ca2+]i set-point. This process, which relies on ubiquitous membrane mechanisms, is likely to play a role in other neuronal types in various brain regions.
authors.affiliation: Department of Neurobiology, Institute of Life Sciences, Hebrew University and the Edmond and Lily Safra Center for Brain Sciences, Jerusalem, Israel.
authors.forename: Asaph
authors.initials: A
authors.lastname: Zylbertal
authors.affiliation: School of Medicine, Department of Medical Neurobiology, Hebrew University, Jerusalem, Israel.
authors.forename: Anat
authors.initials: A
authors.lastname: Kahan
authors.affiliation: School of Medicine, Department of Medical Neurobiology, Hebrew University, Jerusalem, Israel.
authors.forename: Yoram
authors.initials: Y
authors.lastname: Ben-Shaul
authors.affiliation: Department of Neurobiology, Institute of Life Sciences, Hebrew University and the Edmond and Lily Safra Center for Brain Sciences, Jerusalem, Israel.
authors.forename: Yosef
authors.initials: Y
authors.lastname: Yarom
authors.affiliation: Sagol Department of Neurobiology, University of Haifa, Haifa, Israel.
authors.forename: Shlomo
authors.initials: S
authors.lastname: Wagner
mesh_terms: D000818:Animals; D019295:Computational Biology / Q000379:methods; D003712:Dendrites / Q000378:metabolism*; D055724:Electrophysiological Phenomena; D005260:Female; D015640:Ion Channel Gating; D007700:Kinetics; D008297:Male; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D008959:Models, Neurological; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009431:Neural Conduction; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009830:Olfactory Bulb / Q000166:cytology / Q000378:metabolism*; D059010:Single-Cell Analysis; D019831:Sodium-Calcium Exchanger / Q000378:metabolism*; D013047:Specific Pathogen-Free Organisms
chemical_list: D009419:Nerve Tissue Proteins; D019831:Sodium-Calcium Exchanger