Activity of Acetylcholinesterase on the Endolymphatic Surface of Outer Hair Cells

Abstract

By means of the Karnovsky's modification of Koelle's thiocholine method for acetylcholinesterase (AChE), it has been demonstrated electronmicro-scopically that AChE is located on the endolymphatic surface of outer hair cells and not on the supporting cells in the organ of Corti of the guinea pig cochlea. The tissue from the middle part of the basal turn was used in all experiments. The identification of AChE was confirmed by use of appropriate concentration of selective inhibitors of cholines-terase. From the inhibitory effect of fixatives on AChE activity, it was obvious that the activity on the surface of outer hair cells was lower than the activity on the large nerve endings at the bottom of the hair cells.