Endocochlear potential and potassium concentration in endolymph and perilymph of the chinchilla

Guinea pigs and chinchillas were studied for EP and potassium concentrations in scala media and scala tympani using potassium-sensitive microelectrodes. Response of EP to 3 min anoxia was strikingly different in these two species. On the other hand, the resting values for EP and potassium concentrations in endolymph and perilymph were not significantly different. These findings suggest that the different response to anoxia in these two species is due to differences in permeability of the cochlear partitions to the ions.