Introduction
Hearing is an active energy dependent process. In addition to von Békésy's classical model of passive stimulation of the basilar membrane, there are active processes that activate the micromechanics of the cochlea. In the 1980s, motile responses had also been observed in outer hair cells.
The present paper was the first study [Zenner's investigation was the first] to confirm the existence of active contractile mechanisms in the OHC, which are mediated by actin. Actin filaments in the inner ear, originally described in the vestibular organ by Professor Åke Flock, were now described in isolated single outer hair cells of the guinea pig cochlea. These cells contracted in the presence of ATP, and activity inhibited when ATP was replaced by a nucleotide-free medium. It was also shown that the mechanical response required calcium. It is concluded that OHC of the guinea pig cochlea are capable of an actin-mediated active mechanical process dependent on cellular energy. Thus, OHC not only receive sound, but also possess properties of a peripheral mechanical effector.
