Harada N, Han D Y, Komeda M, Yamashita T
Department of Otolaryngology, Kansai Medical University, Osaka, Japan.
Acta Otolaryngol. 1994 Nov;114(6):609-12. doi: 10.3109/00016489409126113.
Intracellular calcium concentrations ([Ca2+]i) in acutely isolated spiral ganglion cells (SGCs) of the guinea pig cochlea were measured using digital imaging microscopy and the Ca(2+)-sensitive fluorescence dye fura-2. L-glutamate increased [Ca2+]i in SGCs with neuritic processes but did not lead to an increase in [Ca2+]i in SGCs without neuritic processes. The depolarization induced by high K+ (150 mM) solution increased [Ca2+]i in both SGCs, with and without neuritic processes. The L-glutamate-induced [Ca2+]i elevation was abolished in the absence of extracellular Ca2+. We thus propose that the increase of [Ca2+]i during L-glutamate stimulation is mainly related to an influx of extracellular Ca2+. The excitatory amino acids, probably L-glutamate, may function as a neurotransmitter of the hair cell-afferent nerve synapse in the guinea pig cochlea.
采用数字成像显微镜和钙敏感荧光染料fura-2测量豚鼠耳蜗急性分离的螺旋神经节细胞（SGCs）内的钙浓度（[Ca2+]i）。L-谷氨酸可使具有神经突的SGCs中的[Ca2+]i升高，但不会导致无神经突的SGCs中的[Ca2+]i升高。高钾（150 mM）溶液诱导的去极化可使有和无神经突的SGCs中的[Ca2+]i均升高。在无细胞外Ca2+的情况下，L-谷氨酸诱导的[Ca2+]i升高被消除。因此，我们认为L-谷氨酸刺激期间[Ca2+]i的增加主要与细胞外Ca2+的内流有关。兴奋性氨基酸，可能是L-谷氨酸，可能作为豚鼠耳蜗毛细胞-传入神经突触的神经递质发挥作用。
