Couloigner V, Teixeira M, Sterkers O, Ferrary E
INSERM U426, Faculté Xavier Bichat, Université Paris 7, France.
Acta Otolaryngol. 1999 Mar;119(2):200-2. doi: 10.1080/00016489950181666.
The aim of this study was to investigate the ionic composition (sodium, potassium) of the luminal fluid in the endolymphatic sac and to correlate it with the transepithelial potential. Experiments were performed in guinea pigs using either an intradural posterior fossa approach or a translabyrinthine approach. The endolymphatic sac transepithelial potential (ESP) was measured and the luminal fluid was sampled. The sodium, potassium and protein concentrations were determined. The results were: i) the luminal fluid in the endolymphatic sac differs in composition from perilymph, on the one hand, and from both cochlear and vestibular endolymph, on the other hand, indicating that the endolymphatic sac maintains chemical (sodium, potassium) and electrical (ESP) gradients; ii) the calculated osmolarity (Na + K) x 2 was about 230 mosm/l; iii) no correlation was observed between sodium and potassium concentrations; iv) large interindividual variations exist from one animal to another, suggesting physiological variations in the functional status of the endolymphatic sac. In conclusion, the variation in composition of the endolymphatic sac luminal fluid reflected variations in ion transport by the epithelium and thus a possible adaptation of the ion transport to different physiopathological conditions.
本研究的目的是调查内淋巴囊腔内液体的离子组成（钠、钾），并将其与跨上皮电位相关联。实验在豚鼠身上进行，采用硬脑膜内后颅窝入路或经迷路入路。测量内淋巴囊跨上皮电位（ESP）并采集腔内液体样本。测定钠、钾和蛋白质浓度。结果如下：i）内淋巴囊腔内液体的组成一方面与外淋巴不同，另一方面与耳蜗和前庭内淋巴均不同，这表明内淋巴囊维持着化学（钠、钾）和电（ESP）梯度；ii）计算得出的渗透压（Na + K）×2约为230 mosm/l；iii）未观察到钠和钾浓度之间存在相关性；iv）不同动物之间存在较大的个体差异，提示内淋巴囊功能状态存在生理变异。总之，内淋巴囊腔内液体组成的变化反映了上皮细胞离子转运的变化，从而表明离子转运可能适应不同的生理病理状况。
