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Network activity in the brain is associated with a transient increase in extracellular K(+) concentration. The excess K(+) is removed from the extracellular space by mechanisms proposed to involve Kir4.1-mediated spatial buffering, the Na(+)/K(+)/2Cl(-) cotransporter 1 (NKCC1), and/or Na(+)/K(+)-ATPase activity. Their individual contribution to [K(+)]o(More)
During neuronal activity in the brain, extracellular K(+) rises and is subsequently removed to prevent a widespread depolarization. One of the key players in regulating extracellular K(+) is the Na(+)/K(+)-ATPase, although the relative involvement and physiological impact of the different subunit isoform compositions of the Na(+)/K(+)-ATPase remain(More)
Neuronal activity results in release of K(+) into the extracellular space of the central nervous system. If the excess K(+) is allowed to accumulate, neuronal firing will be compromised by the ensuing neuronal membrane depolarization. The surrounding glial cells are involved in clearing K(+) from the extracellular space by molecular mechanism(s), the(More)
Aquaporin 4 (AQP4) is the predominant water channel in the mammalian brain and is mainly expressed in the perivascular glial endfeet at the brain-blood interface. AQP4 serves as a water entry site during brain edema formation, and regulation of AQP4 may therefore be of therapeutic interest. Phosphorylation of aquaporins can regulate plasma membrane(More)
Aquaporin 4 (AQP4) is the predominant water channel in the mammalian brain and is mainly expressed in the perivascular glial endfeet at the brain–blood interface. Based on studies on AQP4−/− mice, AQP4 has been assigned physiological roles in stimulus-induced K+ clearance, paravascular fluid flow, and brain edema formation. Conflicting data have been(More)
Presented is a fluorometric technique for the quantitative analysis of taurine in biological samples. The sample is homogenized, treated with picric acid, and passed through a mixed-bed, ion-exchange column. The eluant is lyophilized, reconstituted, and an aliquot derivatized with o-phthalaldehyde (OPA) prior to high performance liquid chromatography(More)
Hepatocyte growth factor activator inhibitor-2 (HAI-2) is an inhibitor of many proteases in vitro, including the membrane-bound serine protease, matriptase. Studies of knock-out mice have shown that HAI-2 is essential for placental development only in mice expressing matriptase, suggesting that HAI-2 is important for regulation of matriptase. Previous(More)
Estrogen metabolism was studied in a newly established cell line (RL95-2) derived from a human endometrial carcinoma. Estradiol and estrone were metabolized to water-soluble derivatives by cells under in vitro culture conditions. Between 80-90% of the added steroids were metabolized, with nearly quantitative recovery of the products from the incubation(More)
KEY POINTS Management of glutamate and K(+) in brain extracellular space is of critical importance to neuronal function. The astrocytic α2β2 Na(+) /K(+) -ATPase isoform combination is activated by the K(+) transients occurring during neuronal activity. In the present study, we report that glutamate transporter-mediated astrocytic Na(+) transients stimulate(More)
Experimental conditions and parameters involved in high performance liquid chromatography (HPLC) separations of the peptide hormone oxytocin and seven of its diastereoisomers, namely [1-hemi-D-cystine]-, [2-D-tyrosine]-, [4-D-glutamine]-, [5-D-asparagine]-, [6-hemi-D-cystine-], [7-D-proline]-, and [8-D-leucine]-oxytocin, on reverse phase columns were(More)