The ionic and electric environment in the endolymphatic sac of the chinchilla: relevance to the longitudinal flow.
The ionic composition of the endolymph in the endolymphatic sac (ES) of the chinchilla was measured using double-barreled ion-selective micro-electrodes. The DC potential of the ES was 9.3 +/- 1.8 mV (N = 18). The K+, Na+, and Cl- concentrations of the ES were 13.3 +/- 4.7 mM (N = 6), 129.0 +/- 8.8 mM (N = 6), and 124.3 +/- 16.6 mM (N = 6), respectively. In light of the chemical potentials of the cochlear endolymph previously reported [Ikeda and Morizono (1989), Hear. Res., 39, 279-286] the pressure gradient of the endolymph between the cochlea and ES was calculated to be 71.5 mmHg at 38 degrees C. The contribution of the osmotic and hydrostatic pressure gradients of the endolymph to the longitudinal flow is discussed.
Department of Otolaryngology, Tohoku University School of Medicine, Sendai, Japan.
K
K
Ikeda
T
T
Morizono
D000818:Animals; D002682:Chinchilla; D004563:Electrochemistry; D004710:Endolymph / Q000502:physiology; D004712:Endolymphatic Sac / Q000502:physiology*; D006874:Hydrostatic Pressure; D007477:Ions; D009997:Osmotic Pressure
D007477:Ions