title: Myelinating satellite oligodendrocytes are integrated in a glial syncytium constraining neuronal high-frequency activity.
abstract: Satellite oligodendrocytes (s-OLs) are closely apposed to the soma of neocortical layer 5 pyramidal neurons but their properties and functional roles remain unresolved. Here we show that s-OLs form compact myelin and action potentials of the host neuron evoke precisely timed Ba(2+)-sensitive K(+) inward rectifying (Kir) currents in the s-OL. Unexpectedly, the glial K(+) inward current does not require oligodendrocytic Kir4.1. Action potential-evoked Kir currents are in part mediated by gap-junction coupling with neighbouring OLs and astrocytes that form a syncytium around the pyramidal cell body. Computational modelling predicts that glial Kir constrains the perisomatic [K(+)]o increase most importantly during high-frequency action potentials. Consistent with these predictions neurons with s-OLs showed a reduced probability for action potential burst firing during [K(+)]o elevations. These data suggest that s-OLs are integrated into a glial syncytium for the millisecond rapid K(+) uptake limiting activity-dependent [K(+)]o increase in the perisomatic neuron domain.
authors.affiliation: Axonal Signalling Group, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
authors.forename: Arne
authors.identifier: 0000-0003-1777-4523
authors.initials: A
authors.lastname: Battefeld
authors.affiliation: Axonal Signalling Group, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Klooster
authors.affiliation: Axonal Signalling Group, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.|Cell Biology, Department of Biology, Faculty of Science, University of Utrecht, 3584 CH Utrecht, The Netherlands.
authors.forename: Maarten H P
authors.initials: MH
authors.lastname: Kole
mesh_terms: D000200:Action Potentials / Q000235:genetics / Q000502:physiology; D000465:Algorithms; D000818:Animals; D015726:Giant Cells / Q000166:cytology / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008854:Microscopy, Electron; D008959:Models, Neurological; D009186:Myelin Sheath / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D009836:Oligodendroglia / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D000098854:Kcnj10 Channel
chemical_list: D000098854:Kcnj10 Channel; D024661:Potassium Channels, Inwardly Rectifying; D011188:Potassium