Determination of the intravesicular ionized sodium concentration in a cell-free brain membrane vesicle preparation using the fluorescent indicator, SBFI.
Determination of the intravesicular ionized sodium concentration in a cell-free brain membrane vesicle preparation using the fluorescent indicator, SBFI.
复制标题
使用荧光指示剂 SBFI 测定无细胞脑膜囊泡制剂中的囊内离子钠浓度。
DOI：
10.1016/0003-2697(92)90100-l
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发表时间：
1992
影响因子：
2.9
通讯作者：
Daniell,LC
中科院分区：
文献类型：
--
作者：
Daniell,LC
使用微囊（一种无细胞脑囊泡制剂）中的荧光 Na 指示剂 SBFI 测量囊内离子化 Na 浓度 (Nai)。通过双激发波长方法监测 SBFI 荧光，波长与 Fura-2 测定细胞内离子钙浓度 (Cai) 常用的波长相同。 SBFI 荧光的校准在脑微囊中进行了可靠的原位校准。静息 Nai 取决于囊外 Na 浓度 (Nao)，在 120 mm 细胞外 Nao 存在的情况下，静息 Nai 约为 36 mm。在哇巴因（一种质膜 Na/K-ATP 酶抑制剂）存在的情况下，Nai 在 60 秒内增加了 27 mm。将微囊重新悬浮在低游离 Ca 浓度（0 至 0.8 mm）的缓冲液中也会增加 Nai，这表明囊外 Ca 浓度 (Cao) 是 Nai 的重要调节剂。对电压敏感的 Na 通道具有活性的生物碱、藜芦定和乌头碱也会增加 Nai。这些结果证明了神经元 Naire 调节的稳态机制的存在，并表明可以使用 SBFI 在无细胞脑囊泡制剂中测量 Naican。
The intravesicular ionized Na concentration (Nai) was measured using the fluorescent Na indicator, SBFI, in microsacs, a cell-free brain vesicle preparation. SBFI fluorescence was monitored by a dual excitation-wavelength method at the same wavelengths commonly employed for Fura-2 determination of intracellular ionized calcium concentrations (Cai). Calibration of SBFI fluorescence was reliably performed in brain microsacs in situ. Resting Naiwas dependent on the extravesicular Na concentration (Nao) and was about 36 mm in the presence of 120 mm extracellular Nao. In the presence of ouabain, an inhibitor of the plasma membrane Na/K-ATPase, Naiincreased by 27 mm over 60 s. Naiwas also increased by resuspension of microsacs in buffers of low free Ca concentrations (0 to 0.8 mm), indicating that the extravesicular Ca concentration (Cao) is an important regulator of Nai. Alkaloids active at voltage-sensitive Na channels, veratridine and aconitine, also increased Nai. These results demonstrate the presence of homeostatic mechanisms for neuronal Nairegulation and show that Naican be measured in a cell-free brain vesicle preparation using SBFI.