K+ waves in brain cortex visualized using a long-wavelength K+-sensing fluorescent indicator.
We synthesized a water-soluble, long-wavelength K(+) sensor, TAC-Red, consisting of triazacryptand coupled to 3,6-bis(dimethylamino)xanthylium, whose fluorescence increased 14-fold at 0-50 mM K(+) with K(+)-to-Na(+) selectivity >30. We visualized K(+) waves in TAC-Red-stained brain cortex in mice during spreading depression, with velocity 4.4 +/- 0.5 mm/min, and K(+) release and reuptake half-times (t(1/2)) of 12 +/- 2 and 32 +/- 4 s, respectively. Aquaporin-4 (AQP4) deletion slowed K(+) reuptake about twofold, suggesting AQP4-dependent K(+) uptake by astroglia.
Padmawar
Prashant
P
Department of Medicine, Cardiovascular Research Institute, 1246 Health Sciences East Tower, University of California, San Francisco, California 94143, USA.
Yao
Xiaoming
X
Bloch
Orin
O
Manley
Geoffrey T
GT
Verkman
A S
AS
D000818:Animals; D051401:Aquaporin 4 / Q000235:genetics / Q000378:metabolism; D001253:Astrocytes / Q000378:metabolism; D001372:Aza Compounds / Q000032:analysis / Q000737:chemistry; D002540:Cerebral Cortex / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000032:analysis* / Q000737:chemistry; D006575:Heterocyclic Compounds, 3-Ring / Q000032:analysis / Q000737:chemistry; D051379:Mice; D018345:Mice, Knockout; D015394:Molecular Structure; D011188:Potassium / Q000032:analysis* / Q000378:metabolism; D012995:Solubility; D013997:Time Factors
C496031:Aqp4 protein, mouse; D051401:Aquaporin 4; D001372:Aza Compounds; D005456:Fluorescent Dyes; D006575:Heterocyclic Compounds, 3-Ring; C505796:TAC-Red; D011188:Potassium