Reversible contraction of isolated mammalian cochlear hair cells

TLDR

The study isolated guinea pig outer hair cells via a micromechanical non‑enzymatic method. Depolarization of isolated guinea pig outer hair cells with 25–125 mM K⁺ induced longitudinal contraction that could be reversed by lowering K⁺ to 5.4 mM, with up to five contraction–relaxation cycles, Ca²⁺‑dependent relaxation, and formation of a visible cytoplasmic network.

Abstract

Outer hair cells were isolated from the guinea pig cochlea using a micromechanical non-enzymatic procedure. Depolarization of outer hair cells in the presence of 25–125 mM K+ was accompanied by a longitudinal contraction of the isolated cells. A decrease of [K+] to 5.4 mM interrupted contraction and induced a relaxation. Individual hair cells were able to undergo as many as 5 cycles of contraction and relaxation. External Ca2+ was required for relaxation of the contracted hair cells. The contractile event led to the production of a visible cytoplasmic network between the supranuclear area and the cuticular plate.