López-Escámez J A, Cañizares F J, Crespo P V, Baeyens J M, Campos A
Department of Histology and Cell Biology, Faculty of Medicine, University of Granada, Spain.
Hear Res. 1994 Jun 1;76(1-2):60-6. doi: 10.1016/0378-5955(94)90087-6.
Gentamicin-induced changes in ionic composition in the otolithic membrane of adult OF1 mice were evaluated in the gelatinous layers of the saccule and utricle by quantitative electron probe X-ray microanalysis. The otolithic membranes were plunge-frozen and freeze-dried to prevent the redistribution of elements. Quantitative analysis was carried out with an energy dispersive detector using the peak-to-background (P/B) ratio method and different salts dissolved in dextran as standards to calibrate the P/B ratio against the concentration of the elements P, S and K in the microprobe. Gentamicin selectively decreased the concentrations of P (P < 0.001) and S (P < 0.01) in the gelatinous membrane of the saccule, and had no effect in the utricle. The concentration of K also increased in the utricular gelatinous membrane (P < 0.05). The mechanism of ototoxicity in the gelatinous membrane is unknown, but the ability of aminoglycosides to block calcium channels may induce disturbances in the ionic equilibrium of the endolymphatic fluid, and thus affect the biochemical composition of the gelatinous membrane. This technique can be useful to evaluate the distribution of ions in the process of drug-induced ototoxicity.
通过定量电子探针X射线微分析法，在成年OF1小鼠球囊和椭圆囊的胶状层中评估庆大霉素诱导的耳石膜离子组成变化。耳石膜经快速冷冻和冻干处理，以防止元素重新分布。使用能量色散探测器，采用峰背比（P/B）法进行定量分析，并以溶解在葡聚糖中的不同盐类作为标准，根据微探针中元素P、S和K的浓度校准P/B比。庆大霉素选择性降低了球囊胶状膜中P（P < 0.001）和S（P < 0.01）的浓度，而对椭圆囊无影响。椭圆囊胶状膜中的K浓度也升高（P < 0.05）。胶状膜耳毒性的机制尚不清楚，但氨基糖苷类药物阻断钙通道的能力可能会引起内淋巴液离子平衡紊乱，从而影响胶状膜的生化组成。该技术有助于评估药物性耳毒性过程中离子的分布情况。
