Couloigner V, Teixeira M, Hulin P, Sterkers O, Bichara M, Escoubet B, Planelles G, Ferrary E
Institut National de la Santé et de la Recherche Médicale U.426, Faculté Xavier Bichat, Université Paris 7, 75870 Paris Cedex 18, France.
Am J Physiol Regul Integr Comp Physiol. 2000 Nov;279(5):R1695-700. doi: 10.1152/ajpregu.2000.279.5.R1695.
The aim of the present work was to assess the effect of various drugs applied locally on the pH of the luminal fluid (pH(lum)) in guinea pig endolymphatic sac. pH(lum) and transepithelial potential, when measured in vivo by means of double-barrelled pH-sensitive microelectrodes, were 7.06 +/- 0.08 and +6.1 +/- 0.34 mV (mean +/- SE; n = 84), respectively, which is consistent with a net acid secretion in the luminal fluid of the endolymphatic sac. Bafilomycin and acetazolamide increased and decreased, respectively, pH(lum). Amiloride, ethylisopropylamiloride, ouabain, and Schering 28080 had no effect on pH(lum). Results obtained with inhibitors of anionic transport systems were inconclusive; e.g., DIDS reduced pH(lum), whereas neither SITS nor triflocin had any effect. We conclude that bafilomycin-sensitive H(+)-ATPase activity accounts for the transepithelial acid gradient measured in the endolymphatic sac and that intracellular and membrane-bound carbonic anhydrase probably participates in regulating endolymphatic sac pH(lum). The relationship between acid pH, endolymph volume, and Ménière's disease remains to be further investigated.
本研究的目的是评估局部应用的各种药物对豚鼠内淋巴囊管腔内液体pH值（pH(lum)）的影响。通过双管pH敏感微电极在体内测量时，pH(lum)和跨上皮电位分别为7.06±0.08和+6.1±0.34 mV（平均值±标准误；n = 84），这与内淋巴囊管腔内液体的净酸分泌一致。巴氟霉素和乙酰唑胺分别使pH(lum)升高和降低。氨氯吡咪、乙基异丙基氨氯吡咪、哇巴因和先灵28080对pH(lum)无影响。阴离子转运系统抑制剂的结果尚无定论；例如，二异丙基氟磷酸（DIDS）降低了pH(lum)，而4-乙酰胺基-4'-异硫氰酸基-2,2'-二磺酸基苯乙烯（SITS）和三氟辛因均无任何影响。我们得出结论，巴氟霉素敏感的H(+)-ATP酶活性是内淋巴囊中测得的跨上皮酸梯度的原因，并且细胞内和膜结合的碳酸酐酶可能参与调节内淋巴囊pH(lum)。酸性pH值、内淋巴体积与梅尼埃病之间的关系仍有待进一步研究。
