Details

Autor(en) / Beteiligte

• Eitelmann, Sara
• Stephan, Jonathan
• Everaerts, Katharina
• Durry, Simone
• Pape, Nils
• Gerkau, Niklas J
• Rose, Christine R

Titel

Changes in Astroglial K + upon Brief Periods of Energy Deprivation in the Mouse Neocortex

Ist Teil von

• International journal of molecular sciences, 2022-04, Vol.23 (9), p.4836

Ort / Verlag

Switzerland: MDPI AG

Erscheinungsjahr

2022

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Malfunction of astrocytic K regulation contributes to the breakdown of extracellular K homeostasis during ischemia and spreading depolarization events. Studying astroglial K changes is, however, hampered by a lack of suitable techniques. Here, we combined results from fluorescence imaging, ion-selective microelectrodes, and patch-clamp recordings in murine neocortical slices with the calculation of astrocytic [K ]. Brief chemical ischemia caused a reversible ATP reduction and a transient depolarization of astrocytes. Moreover, astrocytic [Na ] increased by 24 mM and extracellular [Na ] decreased. Extracellular [K ] increased, followed by an undershoot during recovery. Feeding these data into the Goldman-Hodgkin-Katz equation revealed a baseline astroglial [K ] of 146 mM, an initial K loss by 43 mM upon chemical ischemia, and a transient K overshoot of 16 mM during recovery. It also disclosed a biphasic mismatch in astrocytic Na /K balance, which was initially ameliorated, but later aggravated by accompanying changes in pH and bicarbonate, respectively. Altogether, our study predicts a loss of K from astrocytes upon chemical ischemia followed by a net gain. The overshooting K uptake will promote low extracellular K during recovery, likely exerting a neuroprotective effect. The resulting late cation/anion imbalance requires additional efflux of cations and/or influx of anions, the latter eventually driving delayed astrocyte swelling.