Cytoplasmic laminar bodies in the striate cortex

The fine structure of the neurons in the rat substantia nigra

Three distinct neurons were identified in the substantia nigra of the rat using Golgi, light, and electron microscopic techniques. A large neuron, found in the pars reticulata, is characterized by well-developed RER, a tubular cytoplasmic inclusion, and somatic and dendritic thorns. A medium-sized neuron, found in the pars compacta, has an eccentric nucleus, distinct Nissl bodies, and an inclusion composed of whorls of concentric cisternae. A small neuron, found in both nigral regions, contains a highly invaginated nucleus, fibrous nuclear inclusion, and paucity of cytoplasmic organelles. Its axon synapses around other nigral dendrites. The presence of these neurons was correlated with the efferent projections and function of the substantia nigra.

Complex convolutions in neurons of the dorsal lateral geniculate nucleus of the normal albino rat

The postnatal development of complex convolutions (CCs) of the dorsal lateral geniculate nucleus (LGNd) in normal rats has been studied quantitatively with light microscopy. We report that immature neurons do not contain these scarcely understood organelles, since they can be seen for the first time in very few, mature neurons of the 30 day rat; their number constantly increases during the following 4 months. These cytoplasmic inclusions can be equally seen in the aged rat. CCs are present in neurons of all sizes, except the smallest, which correspond to the interneuron population. Although, morphologically, CCs of the LGNd of the rat are similar, but not identical, to the cytoplasmic multilaminated bodies of the cat, intermediate forms are described.

Dendritic inclusions in the cerebellar granular layer after long term alcohol consumption in adult rats

Whorled multiplanal inclusions up to 1.5 micron in diameter were observed in dendrites of the cerebellar Golgi cells after 6 months of alcohol treatment, increasing in number with time. Inclusions are formed by apposed cytomembranes stacked parallel or in a twisted arrangement. The paired membranes merged into a dense, finely textured material. A close relationship with dendritic smooth endoplasmic reticulum is apparent. A correlation between chronic alcohol intake and the development of these inclusions is shown although, in common with many other types of neuronal cytoplasmic inclusions, their genesis and function remains to be determined.

A quantitative study of the complex laminated body in the lateral geniculate nucleus of the cat

A quantitative study has been made of the proportions and distribution of cells with complex laminated bodies (CLBs) in the lateral geniculate nucleus of the cat. They develop between 55 and about 70 days postnatal and are distributed irregularly across the medio-lateral extent of lamina A. There was no indication that the proportion of cells with CLBs is higher in the region of lamina A where the area centralis is represented, but the proportion in the binocular segment as a whole was higher than for the monocular segment. In kittens reared with unilateral or bilateral eyelid suture the proportions of cells with CLBs was above normal in the deprived laminae and below normal in the undeprived laminae.

The synaptic organization of glomeruli in the magnocellular and parvocellular laminae of the lateral geniculate nucleus in the monkey

The synaptic organization of glomeruli in the magnocellular laminae of the lateral geniculate nucleus in the macaque monkey has been compared quantitatively with that of glomeruli in the parvocellular laminae using a sampling technique based on single sections. It was found that retinal boutons establish comparable total numbers of synapses in glomeruli in single sections in all laminae, but a relatively higher proportion of them are upon presynaptic dendrites in the magnocellular laminae. In addition, more synaptic contacts are made by presynaptic dendrites in the magnocellular laminae, and consequently in a given section glomeruli in these laminae have on average more synapses in them. Neuronal somata in the magnocellular and parvocellular laminae were studied with the light- and electron-microscopes and there were no complex laminated bodies encountered.

Rod-shaped bodies and crystalloid inclusions in ocular vascular endothelia of adult and developing Macaca mulatta

In addition to the usual organelles, endothelial cells of ocular blood vessels and Schlemm's canal in adult and fetal Macaca mulatta, contain two types of inclusions: rod-shaped bodies and crystalloids. The rod-shaped bodies are similar to those first described in arterial endothelia of the rat. They are between 0.2 to 0.35 micrometer in diameter, up to 2.5 micrometers in length, and are membrane bounded. The crystalloid inclusions are up to 1.2 micrometers in diameter and are associated with the granular endoplasmic reticulum. Their crystalline lattice consists of subunits, 28 nm in diameter, which are either arranged in rows separated by amorphous matrix or tightly packed in a honeycomb-like lattice. The rod-shaped bodies are much more numerous than the crystalloids; however, both kinds of inclusions are consistently found in both adult and fetal vessels. The represent normal components of ocular vascular endothelia which appear very early in the development of the eye.

Development of lamellar bodies and subsurface cisterns in pyramidal cells and neuroblasts of hamster cerebral cortex

In pyramidal cells of hamster frontal cortex lamellar bodies and subsurface cisterns sequentially occurred during development from newborn to three months of age. Neither of these two specializations of the rough endoplasmic reticulum was seen in neurons of the newborn. The first specialization that we observed was the subsurface cistern, which appeared at five days and showed a significant increase both in frequency and in length throughout development. The lamellar body was first seen at ten days of age. This specialization showed a peaking of frequency, length, and number of cisterns per body at 15 days, which subsequently decreased gradually to 3-month-old levels. The occurrence of lamellar body-subsurface cistern complexes increased with age. We suggest that the lamellar body may be an ER specialization that is involved in an increased and/or stage-specific protein synthesis in the young prior to the final maturation of the usual neuronal protein synthetic organelles, and that in the 3-month-old neurons, the lamellar body may be involved in modifying, storing or transporting metabolites received from the neuropil components via the subsurface cisterns. The subsurface cistern, on the other hand, by virtue of its location subjacent to the neuronal plasma membrane and of its increased frequency from birth to maturation, may be involved in the exchange of metabolites and nonsynaptic forms of communication at all ages.

Ultrastructure of the Bunina bodies in anterior horn cells of amyotrophic lateral sclerosis

Light and electron microscopic studies were made on the anterior horn cells in a case o amyotrophic lateral sclerosis. Eosinophilic inclusions of Bunina type were observed almost selectively in the motor neurons of spinal cord, as well as of brain stem, at the light microscopic level. Fine structural study revealed the presence of two types of cytoplasmic inclusions. The first, mainly corresponding to the light microscopic inclusions, were homogeneous, electron-dense, round- or oval-shaped bodies with vesicular or tubular rims and ribosome particles, about 2-5 mu in diameter, which contained filaments or other cytoplasmic componenets in the clear areas within them. The second were lamellar structures (laminated cytoplasmic bodies, Morales) which appeared to be originating from endoplasmic reticulum. There was no distinct transition in these two types of inclusions and the relationship to each other is not clear. The significance of Bunina body is unknown, but some manifestation of a primary disorder, e.g., protein metabolism, rather than a secondary degenerative change in the motor neurons in amyotorophic lateral sclerosis.

Ultrastructure of thalamic neuronal inclusions in myotonic dystrophy

Recently, the presence of thalamic neuronal cytoplasmic inclusions in patients with myotonic dystrophy has been reported. At the ultrastructural level, the inclusions were described "containing a fibrillar material within a limiting membrane studded on its outer surface with ribosomes". We have studied the brain of a 48-year-old woman with myotonic dystrophy. Many neuronal inclusion bodies were found within the thalamus, and examined in the electron microscope. Inclusions were found to have an electron density resembling that of nuclear chromatin, were not membrane-bound, and had an internal structure composed of parallel alternating dark and pale lines. We confirm the previously-reported existence of cytoplasmic thalamic neuronal inclusions in myotonic dystrophy, but differ in our observations of their ultrastructural appearance, and note that these inclusions bear no resemblance to previously described inclusion bodies.