Orthogonal arrays of intramembrane particles in the supporting cells of the guinea-pig vestibular sensory epithelium.
Membrane specializations of the contact region between afferent nerve endings and supporting cells of the sensory epithelia of guinea-pig vestibular endorgans were examined by thin-section and freeze-fracture electron microscopy. The calyx-type nerve endings (C-endings) are separated from supporting cells (SC) by a 25-30 nm space. At irregular intervals along the upper lateral surface of supporting cells, the intercellular space narrows markedly to form special close contacts between the C-ending and SC plasma membranes. Freeze-fracture replicas reveal membrane specializations--orthogonal arrays of particulate units--in the region where the close intercellular contacts were found in sections. Orthogonal arrays consisting of from 5 to 20 units were observed on the cytoplasmic (P) fracture face of the lateral SC plasma membrane. These particulate units from a 12 x 12-nm square, and each unit is composed of four 6-nm subunits. Possible roles of the orthogonal arrays are discussed.
Saito
K
K
College of Medical Care and Technology, School of Medicine, Gunma University, Maebashi, Japan.
D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure; D004848:Epithelium / Q000648:ultrastructure; D005260:Female; D005614:Freeze Fracturing; D006168:Guinea Pigs; D008297:Male; D008854:Microscopy, Electron / Q000379:methods; D009475:Neurons, Afferent / Q000648:ultrastructure; D014722:Vestibule, Labyrinth / Q000166:cytology / Q000648:ultrastructure*