Trabecular meshworks in the sinusoidal endothelial cells of the golden hamster liver: a freeze-fracture study.

Abstract

Trabecular meshworks (TMs) in the sinusoidal endothelial cells of fasted-refed golden hamster liver were studied in thin sections and in freeze-fracture replicas. TM was a plasmalemma-attached reticulum of anastomosing trabeculae composed of the plasmalemma and cytosol. The surface of TM appeared as a sieve on the plasmalemma. The floor of TM appeared as a depression with snapped trabeculae on the P-face plasmalemma and as a mound, or inverted depression, with pits containing snapped trabeculae on the E-face plasmalemma. Faint ridges were seen connecting some trabeculae on the P-face plasmalemma, whereas furrows lined with intramembranous particles (IMPs) were seen spanning some trabeculae on the E-face plasmalemma. Circles of lined IMPs (IMP-circles) were seen on the E-face plasmalemma, either alone or in association with TMs. Plasmalemmal invaginations were often centered in IMP-circles and were sometimes seen in a cluster. TMs were often blended with the sieve plates.