Membrane Organelles in Developing Hamster Frontal Cortex

Abstract

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.