Motility of isolated vestibular hair cells induced by potassium

Many studies of the outer hair cells in cochlea have demonstrated active motility. However, very few studies have been done on vestibular hair cells. This study was designed to demonstrate the motile responses of isolated vestibular hair cells of the chick, induced by potassium promoting contraction. Reversible cell shape changes were observed in 4 of 6 type I hair cells and 3 of 5 type II hair cells by applying the contraction solution. The cell shape changes were revealed mainly in the cuticular plate and infracuticular region. It was suggested that contraction in the cuticular plate of the isolated hair cells might be converted into tension which increases the stiffness of the sensory hairs and restricts their motions, based on the results of the present study, and the structure of contractile proteins and hair behaviors reported by previous investigators.