Kitano I, Doi K, Mori N, Umemoto M, Sakagami M, Fukazawa K, Matsunaga T
Department of Otolaryngology, Nara Medical University, Japan.
Hear Res. 1994 Jul;78(1):58-64. doi: 10.1016/0378-5955(94)90044-2.
The effect of forskolin (FSK) on the endocochlear potential (EP), K+ activity (AK), Na+ activity (ANa) and Cl- activity (ACl) in scala media (SM) was compared between normal and kanamycin (KM)-poisoned guinea pigs by means of double-barrelled ion-selective microelectrodes. The perfusion of the scala vestibuli (SV) with FSK (200 microM) produced EP elevation in normal animals whereas FSK failed to do it in KM-poisoned animals. FSK increased ACl of SM with no significant change in AK and ANa of SM in both groups of animals. Histological examination of KM-poisoned animals showed damaged outer and inner hair cells with an intact appearance of the stria vascularis. The mechanism underlying the failure of FSK to elevate the EP in KM-poisoned animals is discussed.
