Domínguez L, Montenegro J, Pasantes-Morales H
Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, D.F.
J Neurosci Res. 1989 Mar;22(3):356-61. doi: 10.1002/jnr.490220317.
Chick retinas exposed to 56 mM KCl showed marked swelling of cells and synaptic structures, detected by morphological examination as well as by measurements of cell water content. Retinal cell swelling is prevented by omission of chloride. Potassium chloride, 56 mM, elicited the efflux of [3H]taurine by a process that is partly calcium-dependent, highly chloride-dependent (80%), and sensitive to furosemide. The release of [3H]dopamine under the same conditions is completely calcium-dependent and increases in the absence of chloride. The chloride-dependent component of [3H]taurine efflux seems related to increases in volume changes since it is markedly reduced when cell swelling is prevented either by maintaining constant the K X Cl product (Donnan equilibrium) or by making the solution hypertonic with mannitol. Omission of calcium and of chloride showed additive effects, practically suppressing the potassium-stimulated release of taurine. These results suggest that the potassium-stimulated efflux of [3H]taurine consists of a large component associated to changes in cell volume and a small component probably related to the depolarizing effects of potassium.
通过形态学检查以及细胞含水量测量发现，暴露于56 mM氯化钾的鸡视网膜显示出细胞和突触结构明显肿胀。通过去除氯离子可防止视网膜细胞肿胀。56 mM的氯化钾通过一个部分依赖钙、高度依赖氯（80%）且对呋塞米敏感的过程引发了[3H]牛磺酸的外流。在相同条件下，[3H]多巴胺的释放完全依赖钙，且在无氯离子时增加。[3H]牛磺酸外流的氯依赖成分似乎与体积变化的增加有关，因为当通过维持钾离子与氯离子乘积恒定（唐南平衡）或用甘露醇使溶液变为高渗来防止细胞肿胀时，该成分会显著减少。去除钙和氯离子显示出累加效应，几乎完全抑制了钾离子刺激的牛磺酸释放。这些结果表明，钾离子刺激的[3H]牛磺酸外流由与细胞体积变化相关的一个大成分和可能与钾离子去极化作用相关的一个小成分组成。
