Iwata H, Yamagami S, Mizuo H, Baba A
J Neurochem. 1982 May;38(5):1268-74. doi: 10.1111/j.1471-4159.1982.tb07900.x.
Uptake and release of cysteine sulfinic acid by synaptosomal fractions (P2) and slices of rat cerebral cortex were investigated. The P2 fraction had a Na+-dependent high-affinity uptake system for cysteine sulfinic acid (Km, 12 microM), which was restricted to the synaptosomes. High-affinity uptake of cysteine sulfinic acid was competitively inhibited by glutamate, aspartate, and cysteic acid. None of the various centrally acting drugs tested specifically inhibited this transport system. Release of [14C]cysteine sulfinic acid from preloaded cortical slices or P2 fractions was examined by a superfusion method, which avoided reuptake of released [14C]cysteine sulfinic acid. High K+ (56 mM) and veratridine (10 microM) stimulated the release of cysteine sulfinic acid from slices and the P2 fraction in a partly Ca2+-dependent manner. Diazepam at concentrations of 10 and 100 microM markedly inhibited the stimulated release, but not the spontaneous release, by cortisol slices. On the contrary, it had no effect on the stimulated release of cysteine sulfinic acid from the P2 fraction.
研究了大鼠大脑皮质突触体组分（P2）和切片对半胱氨酸亚磺酸的摄取和释放。P2组分对半胱氨酸亚磺酸具有钠依赖性高亲和力摄取系统（Km为12微摩尔），该系统仅限于突触体。半胱氨酸亚磺酸的高亲和力摄取受到谷氨酸、天冬氨酸和半胱磺酸的竞争性抑制。所测试的各种中枢作用药物均未特异性抑制该转运系统。通过一种避免再摄取释放的[14C]半胱氨酸亚磺酸的灌注方法，检测了预加载的皮质切片或P2组分中[14C]半胱氨酸亚磺酸的释放。高钾（56毫摩尔）和藜芦碱（10微摩尔）以部分依赖于钙的方式刺激切片和P2组分中半胱氨酸亚磺酸的释放。浓度为10和100微摩尔的地西泮显著抑制皮质醇切片刺激的释放，但不抑制自发释放。相反，它对P2组分中半胱氨酸亚磺酸的刺激释放没有影响。
