ION TRANSPORT AND VOLUME REGULATION IN ASTROCYTES

我们的目标是研究基本的离子传输过程。 参与哺乳动物脑星形胶质细胞的肿胀，使用 原代星形胶质细胞单层培养的特征 新生大鼠的大脑。我们将研究细胞对 暴露在低渗和高渗介质中以表征离子 涉及运量控制的运输过程。我们还将 研究可能的内源性效应因子的影响 等渗条件下的星形细胞肿胀，如乳酸 酸、L-谷氨酸、去甲肾上腺素和升高[K+]o，离子 转运、细胞体积和细胞内pH。我们将使用 不同的放射性示踪剂测量离子传输，细胞 附着单层的体积和细胞内pH 文化。我们将使用标准电生理学来监测 膜电位和电阻的变化，以及氯离子 用特定的微电极直接研究细胞的快速变化 这种离子的细胞内活性。使用分离的单元格 将跟随光散射来观察快速的体积变化 和不同的荧光探针来研究膜电位， 细胞内pH和[Ca~(2+)]i在可比条件下，使用 一种流动细胞荧光仪。星形胶质细胞占20%-30% 哺乳动物中枢神经系统(CNS)。从古典意义上讲，他们是 降级到神经胶或“神经胶质”的作用，甚至 在他们的细胞身份在转折点被建立之后 他们仍然被认为是类似于 结缔组织具有未指明的支持作用 神经元。很明显，它们的属性是 极其复杂，它们的离子传输特性似乎 对它们的功能尤其重要。这些研究 应该促进我们在这方面的知识，并增加一个 对这些在哺乳动物脑中的作用的理解(S) 很少有人研究的细胞。

Our objectives are to study the basic ion transport processes involved in th swelling of mammalian brain astrocytes, using characterized primary astrocyte monolayer cultures from neonatal rat brains. We will study the cells' responses to exposure to hypo- and hypertonic medium to characterize the ion transport processes involved in volume control. We will also study the effects of possible endogenous effectors of astrocytic swelling under isosmotic conditions, such as lactic acid, L-glutamate, norepinephrine and raised [K+]o, on ion transport, cell volume and intracellular pH. We will use different radioactive tracers to measure ion transport, cell volume and intracellular pH in the attached monolayer cultures. We will use standard electrophysiology to monitor membrane potential and resistance changes, and chloride ion specific microelectrodes to directly study rapid changes in the intracellular activity of this ion. Using detached cells we will follow light scattering to look at rapid volume changes and different fluorescent probes to study membrane potential, intracellular pH and [Ca2+]i under comparable conditions, using a flow cytofluorometer. Astrocytes comprise 20-30% of the mammalian central nervous system (CNS). Classically they were relegated to the role of nerve glue or "neuroglia" and even after their cellular identity was established around the turn of the century they were still considered to be analogous to connective tissue with unspecified supportive roles for neurons. It has become clear that their properties are extremely complex, and their ion transport properties appear to be particularly important for their function. The studies should advance our knowledge in this area and add to an understanding of the role(s) in the mammalian brain of these little-studied cells.