Diffusion characteristics and extracellular volume fraction during normoxia and hypoxia in slices of rat neostriatum.
Diffusion characteristics and extracellular volume fraction during normoxia and hypoxia in slices of rat neostriatum.
复制标题
大鼠新纹状体切片常氧和缺氧时的扩散特征和细胞外体积分数。
DOI：
10.1152/jn.1991.65.2.264
复制
发表时间：
1991
影响因子：
2.5
通讯作者：
Nicholson,C
中科院分区：
文献类型：
--
作者：
Rice,ME;Nicholson,C
1.通过定量分析离子导入四甲基铵（TMA+）的浓度-时间曲线，测定了大鼠新纹状体浸没、灌流脑片的扩散特性。在距离源移液管100-150微米的离子选择性微电极（ISM）处感测TMA+。从纹状体内电刺激诱发的细胞外场电位评估切片活力。2.在常氧条件下，在具有良好场电位的切片中，细胞外体积分数（α）为0.21（范围0.18-0.24），迂曲度（λ）为1.54。在场电位差的切片中，α为0.09-0.16。在切片中提取正确的α和λ需要评估非特异性摄取，k '，其为1 x 10（-2）s-1。3.通过灌流用95%N2 - 5%CO2平衡的生理盐水10-30分钟使切片缺氧。在缺氧介质中3-4分钟后，场电位的突触成分被抑制。在一些实验中，用ISM监测细胞外K+浓度[（K+]o）。缺氧期间，[K+]o从平均基线5.1 mM升至7-10 mM。复氧后，[K+]o短暂降至原始水平以下。4.缺氧期间α的平均值为0.13（降低38%），与对照组有显著差异（P <0.001），并在缺氧暴露期间进行性增加。相比之下，弯曲度和k'通过该处理未改变。5.这些数据代表的扩散特性的大鼠纹状体切片和细胞外体积分数的变化在缺氧过程中的脑切片制备的第一个表征。（250字处删节）
1. Diffusion properties of submerged, superfused slices from the rat neostriatum were measured by quantitative analysis of concentration-time profiles of tetramethylammonium (TMA+) introduced by iontophoresis. TMA+ was sensed at an ion-selective microelectrode (ISM) positioned 100-150 microns from the source pipette. Slice viability was assessed from the extracellular field potentials evoked by intrastriatal electrical stimulation. 2. Under normoxic conditions the extracellular volume fraction (alpha) was 0.21 (range 0.18-0.24), and the tortuosity (lambda) was 1.54, in slices with good field potentials. In slices with poor field potentials, alpha was 0.09-0.16. Extraction of correct alpha and lambda in the slice required evaluation of nonspecific uptake, k', which was 1 x 10(-2) s-1. 3. Slices were made hypoxic by superfusing physiological saline equilibrated with 95% N2-5% CO2 for 10-30 min. Synaptic components of field potentials were inhibited after 3-4 min in hypoxic media. In some experiments extracellular K+ concentration [( K+]o) was monitored with ISMs. During hypoxia, [K+]o rose from an average baseline of 5.1 mM to 7-10 mM. After reoxygenation, [K+]o transiently fell below the original level. 4. The average value for alpha during hypoxia was 0.13 (a 38% decrease), which was significantly different from control (P less than 0.001) and increased progressively during hypoxic exposure. In contrast, tortuosity and k' were unchanged by this treatment. 5. These data represent the first characterization of the diffusion properties of the rat striatal slice and of changes in extracellular volume fraction during hypoxia in a brain slice preparation.(ABSTRACT TRUNCATED AT 250 WORDS)