Haj-Yasein NN, Bugge CE, Jensen V, Østby I, Ottersen OP, Hvalby Ø, Nagelhus EA. Deletion of aquaporin-4 increases extracellular K(+) concentration during synaptic stimulation in mouse hippocampus.
Brain Struct Funct 2014;
220:2469-74. [PMID:
24744149 PMCID:
PMC4481334 DOI:
10.1007/s00429-014-0767-z]
[Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 03/28/2014] [Indexed: 11/28/2022]
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.
Collapse