ION TRANSPORT AND VOLUME REGULATION IN ASTROCYTES

我们的目标是研究基本的离子输运过程 参与哺乳动物脑星形胶质细胞的肿胀， 表征的原代星形胶质细胞单层培养物来自 新生大鼠脑。 我们将研究细胞对 暴露于低渗和高渗介质以表征离子 运输过程中涉及的音量控制。 我们还将 研究可能的内源性效应物的影响， 星形胶质细胞在等渗条件下肿胀，如乳酸 酸、L-谷氨酸、去甲肾上腺素和升高的[K+]o，on离子 运输，细胞体积和细胞内pH值。我们将使用 不同的放射性示踪剂来测量离子运输，细胞 粘附单层的体积和细胞内pH cultures. 我们将使用标准的电生理学来监测 膜电位和电阻的变化，以及氯离子 特定的微电极，直接研究快速变化， 这种离子的细胞内活性。 使用分离的细胞， 将跟踪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 流式细胞荧光计。 星形胶质细胞占20-30%， 哺乳动物中枢神经系统（CNS）。 典型地， 被降级为神经胶或“神经胶质”的角色， 在他们的细胞身份在转弯处被确定后， 在世纪， 结缔组织，具有未指明的支持作用， 神经元 很明显，它们的性质是 非常复杂，它们的离子传输特性似乎 这对他们的功能尤为重要。 研究 应该提高我们在这方面的知识，并增加一个 了解这些在哺乳动物大脑中的作用 很少被研究的细胞

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.