Proportionality of intracellular resistance changes and receptor potentials in hair-cell models

Russell and Sellick (Russell, I.J. and Sellick, P.M. (1978): J. Physiol. (London) 284, 261–290) reported measurements in guinea pig inner hair cells of d.c. resistance and d.c. potential changes in response to tones delivered to the tympanic membrane. They reported that d.c. potential changes were proportional to d.c. resistance changes for a broad range of tone levels and frequencies, and concluded that this result is inconsistent with the variable-resistance model proposed by Davis (Davis, H. (1958): Ann. Otol. Rhinol. Laryngol. 67, 789–801). We show that this proportionality is consistent with the model. Furthermore, we show that such proportionality is a special case of a general property of a model that is a generalization of the Davis model. Namely, we show that the time-varying receptor potential is proportional to the time-varying resistance change.