Estevez A Y, O'Regan M H, Song D, Phillis J W
Department of Physiology, School of Medicine, Wayne State University, Detroit MI 48201, USA.
Neurochem Res. 1999 Mar;24(3):447-52. doi: 10.1023/a:1020902104056.
A cortical cup model with continuous perfusion of artificial cerebrospinal fluid (containing 134 mM NaCl) was used to investigate the effects of anion channel blockers on the hyposmotically-induced release of amino acids from the in vivo rat cerebral cortex. The hyposmotic stimulus (25 mM NaCl) evoked a release of taurine, glutamate, aspartate, glycine, phosphoethanolamine and GABA. Topically applied anion channel blockers 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (1 mM); 4-acetamido-4'-isothiocyanatostilbene-2,2-disulfonic acid (2 mM); 5-nitro-2-(3-phenylpropylamino) benzoic acid (350 microM); niflumic acid (500 microM); tamoxifen (20 microM) and arachidonic acid (0.5 microM) all significantly reduced the hyposmotically-induced release of taurine. The releases of glutamate, aspartate, glycine, phosphoethanolamine and GABA were variably susceptible to inhibition by these compounds. These results demonstrate that osmoregulatory processes in cortical cells, in vivo, involve amino acids, with taurine playing a dominant role. The efflux of taurine and, to a lesser extent, the other amino acids may be mediated by anion channels.
采用一种可连续灌注人工脑脊液（含134 mM氯化钠）的皮质杯模型，研究阴离子通道阻滞剂对低渗诱导的体内大鼠大脑皮质氨基酸释放的影响。低渗刺激（25 mM氯化钠）可引起牛磺酸、谷氨酸、天冬氨酸、甘氨酸、磷酸乙醇胺和γ-氨基丁酸的释放。局部应用阴离子通道阻滞剂4,4'-二异硫氰基芪-2,2'-二磺酸（1 mM）；4-乙酰氨基-4'-异硫氰基芪-2,2-二磺酸（2 mM）；5-硝基-2-（3-苯丙基氨基）苯甲酸（350 microM）；氟灭酸（500 microM）；他莫昔芬（20 microM）和花生四烯酸（0.5 microM）均显著降低低渗诱导的牛磺酸释放。谷氨酸、天冬氨酸、甘氨酸、磷酸乙醇胺和γ-氨基丁酸的释放对这些化合物的抑制作用敏感性各异。这些结果表明，体内皮质细胞的渗透调节过程涉及氨基酸，其中牛磺酸起主导作用。牛磺酸以及程度较轻的其他氨基酸的外流可能由阴离子通道介导。
