1. Deletion of aquaporin-4 increases extracellular K(+) concentration during synaptic stimulation in mouse hippocampus.
- Author
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Haj-Yasein NN, Bugge CE, Jensen V, Østby I, Ottersen OP, Hvalby Ø, and Nagelhus EA
- Subjects
- Animals, Aquaporin 4 genetics, Electric Stimulation, In Vitro Techniques, Ion-Selective Electrodes, Mice, Mice, Transgenic, Aquaporin 4 deficiency, Extracellular Space metabolism, Hippocampus metabolism, Potassium metabolism, Synapses physiology
- Abstract
The coupling between the water channel aquaporin-4 (AQP4) and K(+) transport has attracted much interest. In this study, we assessed the effect of Aqp4 deletion on activity-induced [K(+)]o changes in acute slices from hippocampus and corpus callosum of adult mice. We show that Aqp4 deletion has a layer-specific effect on [K(+)]o that precisely mirrors the known effect on extracellular volume dynamics. In CA1, the peak [K(+)]o in stratum radiatum during 20 Hz stimulation of Schaffer collateral/commissural fibers was significantly higher in Aqp4 (-/-) mice than in wild types, whereas no differences were observed throughout the [K(+)]o recovery phase. In stratum pyramidale and corpus callosum, neither peak [K(+)]o nor post-stimulus [K(+)]o recovery was affected by Aqp4 deletion. Our data suggest that AQP4 modulates [K(+)]o during synaptic stimulation through its effect on extracellular space volume.
- Published
- 2015
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