[Physiological nuclear size pattern of sensory cells in the guinea pig cochlea]

The present investigations has been carried out in order to get a base for quantitative recording of nuclear size changes of guinea pig cochlear sensory cells which are be found after noise exposure. The nuclei of normal cochlear hair cells differ in size. Inner hair cell nuclei are rapidly increasing in size at the first third of the basal turn and reach a maximum at the transition to the second turn. Up to the cochlear apex they are decreasing in size until they have reached the size of the lower basal turn again. Outer hair cell nuclei are clearly smaller than inner hair cell nuclei in the first three turns. From basal to apical outer hair cell nuclei show an almost linear increasing in size and at the end of the fourth turn they are nearly comparable with those of inner hair cells. There are no significant differences in nuclear size between the three rows of outer hair cells in the first and second turn. In the third turn however an increase of size of outer hair cell nuclei from medial ot lateral could be found.