Orthogonal arrays of particles in astroglial cells: Quantitative analysis of their density, size, and correlation with intramembranous particles

Astroglial cells were investigated by means of freeze-fracture in normal rat and mouse brain, cell culture and human gliomas. Membranes of these cells were quantitatively analyzed for their intramembranous particles (IMPs) and orthogonal arrays of particles (OAPs). Measurement of the size of OAPs and IMPs has permitted the search for a correlation between the 7-nm IMPs, which are distributed randomly in the membrane, and the subunits of OAPs (OAP-Su, also 7 nm in diameter). Using cultured astroglial cells treated with basic fibroblast growth factor (bFGF), arginine vasopressin, or sorbitol, good evidence for a relationship between the density of 7-nm IMPs and the size of OAPs can be demonstrated. These findings led to a hypothetical model of OAP modulation. A preliminary report has been published elsewhere (Neuhaus and Wolburg, 1989).