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Electrochemical heterogeneity of the cochlear endolymph: effect of acetazolamide.
Am J Physiol. 1984 Jan; 246(1 Pt 2):F47-53.AJ

Abstract

The electrochemical composition of endolymph (EL) of two adjacent cochlear turns was studied in anesthetized rats. Differences in [K]EL, [Cl]EL, and endocochlear potential (EP) were found between the basal turn (165.6 +/- 3.0 mM, n = 14; 144.6 +/- 2.1 mM, n = 14;96.6 +/- 1.9 mV, n = 5, respectively) and the middle turn (155.7 +/- 2.5 mM, n = 15; 133.2 +/- 1.5 mM, n = 15; 87.0 +/- 1.6 mV, n = 6, respectively). The pH values of inner ear fluids were evaluated with 5,5-dimethyloxazolidine-2,4-dione: EL pH of either turn was not different from blood and perilymph (PL) pH. Acetazolamide (40 mg X kg body wt-1) reduced EP and [Cl]EL at each turn by about 20 and 6%, respectively, but [K]EL was unchanged. The electrochemical differences between the two turns persisted. Acetazolamide produced a 0.2-unit decrease in blood pH while the pH values of EL and PL remained unchanged. These results suggest the existence of an electrochemical gradient within EL from the base to the apex of the cochlea involving K+ and Cl- concentrations. H+ and HCO-3 do not appear to participate in this gradient, and the acid-base status in EL could be maintained both by active H+ transport into EL and by HCO-3 formation in the cochlear epithelium.

Authors

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Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

6696078

Citation

Sterkers, O, et al. "Electrochemical Heterogeneity of the Cochlear Endolymph: Effect of Acetazolamide." The American Journal of Physiology, vol. 246, no. 1 Pt 2, 1984, pp. F47-53.
Sterkers O, Saumon G, Tran Ba Huy P, et al. Electrochemical heterogeneity of the cochlear endolymph: effect of acetazolamide. Am J Physiol. 1984;246(1 Pt 2):F47-53.
Sterkers, O., Saumon, G., Tran Ba Huy, P., Ferrary, E., & Amiel, C. (1984). Electrochemical heterogeneity of the cochlear endolymph: effect of acetazolamide. The American Journal of Physiology, 246(1 Pt 2), F47-53.
Sterkers O, et al. Electrochemical Heterogeneity of the Cochlear Endolymph: Effect of Acetazolamide. Am J Physiol. 1984;246(1 Pt 2):F47-53. PubMed PMID: 6696078.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Electrochemical heterogeneity of the cochlear endolymph: effect of acetazolamide. AU - Sterkers,O, AU - Saumon,G, AU - Tran Ba Huy,P, AU - Ferrary,E, AU - Amiel,C, PY - 1984/1/1/pubmed PY - 1984/1/1/medline PY - 1984/1/1/entrez SP - F47 EP - 53 JF - The American journal of physiology JO - Am. J. Physiol. VL - 246 IS - 1 Pt 2 N2 - The electrochemical composition of endolymph (EL) of two adjacent cochlear turns was studied in anesthetized rats. Differences in [K]EL, [Cl]EL, and endocochlear potential (EP) were found between the basal turn (165.6 +/- 3.0 mM, n = 14; 144.6 +/- 2.1 mM, n = 14;96.6 +/- 1.9 mV, n = 5, respectively) and the middle turn (155.7 +/- 2.5 mM, n = 15; 133.2 +/- 1.5 mM, n = 15; 87.0 +/- 1.6 mV, n = 6, respectively). The pH values of inner ear fluids were evaluated with 5,5-dimethyloxazolidine-2,4-dione: EL pH of either turn was not different from blood and perilymph (PL) pH. Acetazolamide (40 mg X kg body wt-1) reduced EP and [Cl]EL at each turn by about 20 and 6%, respectively, but [K]EL was unchanged. The electrochemical differences between the two turns persisted. Acetazolamide produced a 0.2-unit decrease in blood pH while the pH values of EL and PL remained unchanged. These results suggest the existence of an electrochemical gradient within EL from the base to the apex of the cochlea involving K+ and Cl- concentrations. H+ and HCO-3 do not appear to participate in this gradient, and the acid-base status in EL could be maintained both by active H+ transport into EL and by HCO-3 formation in the cochlear epithelium. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/6696078/Electrochemical_heterogeneity_of_the_cochlear_endolymph:_effect_of_acetazolamide_ L2 - http://journals.physiology.org/doi/full/10.1152/ajprenal.1984.246.1.F47?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -