Homeostasis of endolymph pH and Ca^<2+>

内淋巴液是细胞外液，但其组成独特，K^+含量高，Na^+、Ca^<2+>含量低。Cl^-、HCO_3^-以阴离子形式存在。本研究采用离子选择性微电极在恒定呼吸条件下测定内淋巴pH值，同时进行血气分析，并结合生理生化指标，对内淋巴pH值的变化规律进行了初步探讨。内淋巴pH值为7.59±0.108（平均值±标准差）（n=10），血pH值为7.57±0.067，血CO_2分压为22.6± 2.44mmHg，血HCO_3^-为19.8±2.45mEq/l。与内淋巴pH和血液pH的相关系数为0.85。血CO_2分压与内淋巴pH值呈负相关，HCO_3^-与内淋巴pH值呈正相关，HCO_3^-与内淋巴pH值呈显著正相关。内淋巴液的pH值由HCO_3^-/CO_2缓冲系统维持，而不是仅由血CO_2分压决定。HCO_3^-在内耳中的产生和转运机制参与了内淋巴pH的调节，有必要进一步阐明内淋巴pH的调控机制，以了解内耳的一般生理和病理生理

Endolymph is extracellular-fluid, but it has a unique composition where K^+ is high and Na^+, Ca^<2+> are low. Cl^-, HCO_3^- exist in as the main anion. It thinks that the HCO_3^- and CO_2 are working as the main buffer-system with the endolymph pH stabilization because proteins, phosphoric acids are hardly contained in the endolymph.In the research this time, the endolymph pH was measured using the ion-selective microelectrode under constant breathing condition, and blood-gas-analysis at the same time. The endolymph pH was 7.59±0.108 (average±SD)(n=10), the blood-pH was 7.57±0.067, the blood CO_2 partial pressure was 22.6±2.44 mmHg and blood HCO_3^- was 19.8±2.45mEq/1. The coefficient of correlation with endolymph pH and blood-pH was 0.85. The blood CO_2 partial pressure had negative corr-elation, the blood HCO_3^- had a positive corr-elation with the endolymph pH, and the corr-elation with blood HCO_3^- was significant. Endolymph pH was maintained by HCO_3^-/CO_2 buffer-system, it wasn't fixed only by the blood CO_2 partial pressure. The production and transport-mechanism of HCO_3^- in the inner ear will participated in endolyph pH. it is necessary to make the controlling mechanism of the endolymph pH clear more understanding a inner ear general physiology and pathophysiology