The investigation of the hypothesis, glutamate-Ca-nitric oxide (NO), in the inner ear disturbance

为探讨一氧化氮(NO)在内耳损伤中的作用，将一氧化氮供体三氮烯(1-Hydroxy-2-oxo-3-(3-aminopropyl)-3-isopropyl-1-triazene，NOC-5)分别置于0.5和0.1摩尔浓度(MC)的豚鼠耳蜗圆窗处，分别于作用后12、28、72h观察其形态变化。内耳毛细胞以细胞凋亡的方式死亡，谷氨酸诱导耳蜗外毛细胞死亡。我们研究了补充半胱氨酸对耳蜗外毛细胞变性的影响。由长期接触Glu引起的。补充半胱氨酸可显著减少死亡毛细胞的数量。我们观察了细胞色素c在链霉素损伤的前庭毛细胞中的细胞定位。提示细胞色素c的再分布参与了氨基糖苷类药物诱导的前庭毛细胞的凋亡途径。我们观察了慢性GLU染毒后豚鼠耳蜗Corti器官的变性。同时，未发现合酶(NOS)活性。用谷氨酸处理后的豚鼠前庭上皮细胞出现时间依赖性变性，同时CORTI器官中的NOS活性也有时间上的升高。我们用烟酰胺腺嘌呤二核苷酸磷酸二核苷酸-黄递素酶染色来检测链霉素影响的豚鼠前庭上皮细胞的NOS活性。在受影响的上皮细胞中观察到NUS活性以剂量和时间依赖的方式增加，一氧化氮合酶抑制剂可以保护毛细胞免受凋亡。此外，放线菌酮显著降低了一氧化氮合酶活性和细胞凋亡的发生。提示NO参与了氨基糖苷类药物引起的前庭上皮退变过程。

We investigated effect of Nitric oxide (NO) in the inner ear disturbances.The two concentrations, 0.5 and 0.1 molar concentration (MC) of 1-Hydroxy-2-oxo-3-(3-aminopropyl)-3-isopropyl-1 -triazene (NOC-5) which is NO donor was placed on the round window of the guinea pig cochlea and its morphological changes were investigated at 12, 28, 72 h after the treatment. The inner ear hair cell died in the manner of apoptosis.Glu induced death of cochlear outer hair cells (OHCs). We investigated the effect of cystine supplementation on degeneration of cochlear outer hair cells (OHCs). caused by long-term exposure to Glu.. Supplementation of cystine significantly decreased the number of dying OHCs..We examined the cellular location of cytochrome c in streptomycin-damaged vestibular hair cells. suggesting that redistribution of cytochrome c is involved in the pathway of apoptosis in vestibular hair cells induced by aminoglycosides..We examined guinea pig cochleae following chronic exposure to GLU to evaluate degeneration in the organ of Corti. In parallel, NO synthase (NOS) activity was demonstrated.. GLU treatment caused time-dependent degeneration of OHCs in conjunction with a temporal increase of NOS activity in the organ of Corti..We used nicotinamide adenine dinucleotide phosphate-diapholase staining to monitor NOS activity during degeneration of guinea pig vestibular epithelia affected by streptomycin. Increased NUS activity was observed in affected epithelia in a dose- and time-dependent manner and a NOS inhibitor could protect hair cells from apoptosis. Additionally, cycloheximide significantly reduced NOS activity and the occurrence of apoptosis. These findings suggest tha NO is involved in the degenerative process of vestibular epithelia caused by aminoglycosides.