Electrochemical aspects of cations in the cochlear hair cell of the chinchilla: a cellular model of the ion movement

Summary The dc potential and ion composition (K⁺, Na⁺, and Ca⁺⁺) in the hair cells of the cochlea were examined using ion-selective microelectrodes. The K⁺, Na⁺, and Ca⁺⁺ concentrations were 124.0 ± 29.8 mM, 6.9 ± 4.1 mM, and 1.7 ± 1.4 M in the hair cells, respectively. The electrochemical potential gradients for K⁺, Na⁺, and Ca⁺⁺ across the apical membranes of the hair cells were calculated to be 160.0 ± 29.8 mV, 87.6 ± 27.0 mV, and 194.4 ± 35.2 mV, respectively. Those for K⁺, Na⁺, and Ca⁺⁺ across the basolateral membranes of the hair cells were –12.6 ± 33.3 mV, 126.8 ± 28.3 mV, and 170.8 ± 30.1 mV, respectively. These findings were discussed in light of the transport mechanism necessary to maintain the ionic composition of hair cells.