Endoplasmic Reticulum Specializations in Aging Hamster Neurons

Rough endoplasmic reticulum has been observed in specialized forms, including the lamellar body (LB) the subsurface cistern (SSC) and a combination of the two known as the lamellar body/sursurface cistern (LB/SSC, Fig. 1) complex. These structures have been described in the neurons of various developing and adult mammals. However, there are no published quantitative reports of these endoplasmic reticulum specializations (ERS) over the life span of a species. In this investigation, quantitative changes were studied in 15- (immature), 100-, 500-(mature), 600- and 700-day (aged) postnatal pyramidal neurons in the frontal cortex of golden hamsters (Mescricetus auratus).The anesthetized animals were perfused with glutaraldehyde-paraformaldhyde in sodium cacodylate buffer (pH 7.3) after the method of Peters. Tissue samples were post-fixed in 2% osmium tetroxide, dehydrated in acetone and embedded in Epon-Araldite resin. Lengths were obtained with the BioQuant Image Analyzer (R & M Biometrics, Nashville, TN).

Membrane Organelles in Developing Hamster Frontal Cortex

Changes in the morphology of the protein-synthetic organelles in pyramidal cells from the frontal cortex were studied in the newborn, 5-, 10-, 15-, 20- day, and adult golden hamster (Mesocricetus auratus). The rough endoplasmic reticulum (RER) was of special interest since it forms the characteristic Nissl substance of adult neurons, as well as other occasional specializations including the subsurface cistern, the lamellar body, the nebenkem, the multilaminated body, the annulate lamella, and the spine apparatus. During the course of this investigation, a sequential pattern was noted in the appearance of the subsurface cisterns and the lamellar bodies, which were the only two specializations of RER observed.The animals were perfused with glutaraldehyde-paraformaldehyde in cacodylate buffer (pH 7.3) after the method of Peters. Tissue samples were subsequently post-fixed in 2% osmium tetroxide, dehydrated in acetone, and embedded in Epon-Araldite resin.