Cultured rat astrocytes possess Na<sup>+</sup>‐Ca<sup>2+</sup> exchanger
この論文をさがす
抄録
<jats:title>Abstract</jats:title><jats:p>Na<jats:sup>+</jats:sup>‐Ca<jats:sup>2+</jats:sup> exchange activity in its reverse mode was demonstrated in cultured rat astrocytes. Combination of ouabain (1 mM) and monensin (20 ±M) caused a marked increase in <jats:sup>45</jats:sup>Ca<jats:sup>2+</jats:sup> uptake in astrocytes. <jats:sup>45</jats:sup>Ca<jats:sup>2+</jats:sup> uptake was also stimulated by lowering the external Na<jats:sup>+</jats:sup> concentration. Ouabain plus monensin‐stimulated <jats:sup>45</jats:sup>Ca<jats:sup>2+</jats:sup> uptake was blocked by 3,4‐dichlorobenzamil (IC<jats:sup>50</jats:sup>, 16 ±M), an inhibitor of Na<jats:sup>+</jats:sup>‐Ca<jats:sup>2+</jats:sup> exchanger, but not by nifedipine (0.1 ±M). The stimulated‐<jats:sup>45</jats:sup>Ca<jats:sup>2+</jats:sup> uptake was observed even in K<jats:sup>+</jats:sup>‐free medium, and external K<jats:sup>+</jats:sup> at 5‐10 mM caused a 2.2‐fold increase in the uptake. Microspectrofluorimetry using the Ca<jats:sup>2+</jats:sup>‐sensitive dye fura‐2 showed that ouabain plus monensin increased intracellular Ca<jats:sup>2+</jats:sup> concentration in single astrocytes. The Ca<jats:sup>2+</jats:sup> signal was dependent on external Ca<jats:sup>2+</jats:sup> (EC<jats:sup>50</jats:sup>, 1.4 mM), and blocked by 20 ±M 3,4‐dichlorobenzamil, but not by Ca<jats:sup>2+</jats:sup> channel blockers (Cd<jats:sup>2+</jats:sup>, 20 ±M; Ni<jats:sup>2+</jats:sup>, 100 ±M). Antiserum of cardiac Na<jats:sup>+</jats:sup>‐Ca<jats:sup>2+</jats:sup> exchanger recognized 160 and 120‐135 kDa proteins on SDS‐polyacrylamide gel electrophoresis of astrocyte homogenate. Northern blot analysis revealed the presence of mRNA for the exchanger protein in astrocytes. These findings indicate that Na<jats:sup>+</jats:sup>‐Ca<jats:sup>2+</jats:sup> exchanger which is modulated by K<jats:sup>+</jats:sup> is present in cultured rat astrocytes.</jats:p>
収録刊行物
-
- Glia
-
Glia 12 (4), 336-342, 1994-12
Wiley
- Tweet
詳細情報
-
- CRID
- 1361137045569384832
-
- NII論文ID
- 30011892109
-
- NII書誌ID
- AA10687234
-
- ISSN
- 10981136
- 08941491
- http://id.crossref.org/issn/08941491
-
- データソース種別
-
- Crossref
- CiNii Articles