Connections between stereocilia in auditory hair cells of the alligator lizard

The interconnections between stereocilia within individual tufts of auditory hair cells in the basilar papilla of the alligator lizard were examined with a transmission electron microscope. An elaborate array of fibers near the base of each stereocilium (where it tapers to anchor into the cuticular plate) connected it to each of its neighboring stereocilia. The tips of individual stereocilia, which were slightly larger in diameter than their shaft, contacted adjacent stereocilia. Fibers also connected the tip of the kinocilium to neighboring stereocilia in the first row. The remaining regions of the stereocilia were relatively free of connecting fibers. The integrity of these connecting fibers are likely to be important in maintaining the normal micromechanical tuning and mechanoelectric transduction in these auditory hair cells. The addition of 0.1% ruthenium red to the primary fixative enhanced the preservation of the connecting structures, implying the presence of glycosaminoglycans.