[Development of intercellular junction in the human vestibular receptors. A freeze-fracture study].

The intercellular junctions, especially the tight junctions of the inner ear end-organs are considered to act as a barrier to maintain gradients of ions between the endolymph and the perilymph. Thus, the intercellular junctions are of great importance for the function of the inner ear. We have studied the development of intercellular junctions in vestibular end-organs in order to establish a morphological basis for better understandings of the key stage of the development of vestibular end-organs. In the present article, the development and maturation of intercellular junctions in human vestibular receptors were observed with freeze-fracture technique. Junctional complex was already present during 8 weeks of gestation. During 8-11 weeks, a rapid development was seen in the intercellular junctions, so that this period seemed to be the key stage in the development and maturation of intercellular junctions. By the end of 11 weeks, the intercellular junctions had possessed the mature appearance as those seen in adults.