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Perilymph composition in scala tympani of the cochlea: influence of cerebrospinal fluid.
Hear Res. 1989 Nov; 42(2-3):265-71.HR

Abstract

A commonly used technique to obtain cochlear perilymph for analysis has been the aspiration of samples through the round window membrane. The present study has investigated the influence of the volume withdrawn on sample composition in the guinea pig. Samples of less than 200 nl in volume taken through the round window showed relatively high glycine content, comparable to the level found in samples taken from scala vestibuli. If larger volumes are withdrawn, lower glycine levels are observed. This is consistent with cerebrospinal fluid (having a low glycine content) being drawn into scala tympani through the cochlear aqueduct and contaminating the sample. The existence of a concentration difference for glycine between scala tympani perilymph and cerebrospinal fluid suggests the physiologic communication across the cochlear aqueduct is relatively small in this species. The observation of considerable exchange between cerebrospinal fluid and perilymph, as reported in some studies, is more likely to be an artifact of the experimental procedures, rather than of physiologic significance. Alternative sampling procedures have been evaluated which allow larger volumes of uncontaminated scala tympani perilymph to be collected.

Authors+Show Affiliations

Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

2606807

Citation

Hara, A, et al. "Perilymph Composition in Scala Tympani of the Cochlea: Influence of Cerebrospinal Fluid." Hearing Research, vol. 42, no. 2-3, 1989, pp. 265-71.
Hara A, Salt AN, Thalmann R. Perilymph composition in scala tympani of the cochlea: influence of cerebrospinal fluid. Hear Res. 1989;42(2-3):265-71.
Hara, A., Salt, A. N., & Thalmann, R. (1989). Perilymph composition in scala tympani of the cochlea: influence of cerebrospinal fluid. Hearing Research, 42(2-3), 265-71.
Hara A, Salt AN, Thalmann R. Perilymph Composition in Scala Tympani of the Cochlea: Influence of Cerebrospinal Fluid. Hear Res. 1989;42(2-3):265-71. PubMed PMID: 2606807.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Perilymph composition in scala tympani of the cochlea: influence of cerebrospinal fluid. AU - Hara,A, AU - Salt,A N, AU - Thalmann,R, PY - 1989/11/1/pubmed PY - 1989/11/1/medline PY - 1989/11/1/entrez SP - 265 EP - 71 JF - Hearing research JO - Hear Res VL - 42 IS - 2-3 N2 - A commonly used technique to obtain cochlear perilymph for analysis has been the aspiration of samples through the round window membrane. The present study has investigated the influence of the volume withdrawn on sample composition in the guinea pig. Samples of less than 200 nl in volume taken through the round window showed relatively high glycine content, comparable to the level found in samples taken from scala vestibuli. If larger volumes are withdrawn, lower glycine levels are observed. This is consistent with cerebrospinal fluid (having a low glycine content) being drawn into scala tympani through the cochlear aqueduct and contaminating the sample. The existence of a concentration difference for glycine between scala tympani perilymph and cerebrospinal fluid suggests the physiologic communication across the cochlear aqueduct is relatively small in this species. The observation of considerable exchange between cerebrospinal fluid and perilymph, as reported in some studies, is more likely to be an artifact of the experimental procedures, rather than of physiologic significance. Alternative sampling procedures have been evaluated which allow larger volumes of uncontaminated scala tympani perilymph to be collected. SN - 0378-5955 UR - https://www.unboundmedicine.com/medline/citation/2606807/Perilymph_composition_in_scala_tympani_of_the_cochlea:_influence_of_cerebrospinal_fluid_ L2 - https://linkinghub.elsevier.com/retrieve/pii/0378-5955(89)90150-0 DB - PRIME DP - Unbound Medicine ER -