Cytoplasmic Inclusions Resembling Nucleoli in Sympathetic Neurons of Adult Rats

Abstract

A distinctive cytoplasmic inclusion consisting of a convoluted network of electron-opaque strands embedded in a less dense matrix was identified in the neurons, but not in the supporting cells, of rat sympathetic ganglia . This ball-like structure, designated "nematosome," measures -0 .9 .s and lacks a limiting membrane . Its strands (diameter = 400-600 A) appear to be made of an entanglement of tightly packed filaments and particles -25-50 A thick . Cytochemical studies carried out with the light microscope suggest the presence of nonhistone proteins and some RNA . Usually only one such structure is present in a cell, and it appears to occur in most ganglion cells . Although they can be seen anywhere in the cell body, nematosomes are typically located in the perinuclear cytoplasm, where they are often associated with smooth-surfaced and coated vesicles . In fine structure and stainability, they bear a resemblance to the fibrous component of the nucleolus . Subsynaptic formations, which are a special feature of some of the synapses in sympathetic ganglia, appear similar to the threadlike elements in the nematosomes . The possibility that these three structures-nucleolus, nematosome, and subsynaptic formation-may be interrelated in origin and function is discussed .

A Possible Mechanism for the Nucleolar Extrusion in Nerve Cells of the Mouse Hypothalamus

“…The intracytoplasmic nucleolus-like inclusion body has been frequently observed in nerve cells (BACHRACH, 1957;Sakai, 1964;KAWABATA, 1965;SHIMIZU and ISHII, 1965;GRILLO, 1970). In the present observations the inclusion bodies had no limiting membrane, being free in the cytoplasm.…”

“…They have also been frequently observed in nerve cells, i.e. in the rat sympathetic ganglia (GRILLO, 1970) and in the rat hypothalamic nuclei (BACHRACH, 1957;SAKAI, 1964;KAWABATA, 1965;SHIMIZU and ISHII, 1965). Such inclusion bodies have been assumed to derive from the intranuclear nucleolus, but no direct morphological evidence has been offered.…”

Stigmoid Bodies Contain Type I Receptor Proteins SorLA/LR11 and Sortilin: New Perspectives on Their Function

“…They received their specific name in the early 1990s when antibodies to a complex of proteins originating from placental tissue were able to detect them in the brain of rats (Shinoda et al 1993). References in the literature concerning cytoplasmic structures that are ultrastructurally identical to SBs are very numerous, and structures resembling SBs have been called "nucleolus-like bodies," "cytoplasmic nucleoli," "nematosomes" (Shimizu and Ishii 1965;Grillo 1970), "cytoplasmic bodies" (Weakley 1969), "basophilic intracellular granules" (Hindelang-Gertner et al 1974), and "giant filamentous inclusions" (Blazquez et al 1995). With non-immunostained electron microscopic preparation, SBs are visible in the cytoplasm of neurons (Leranth et al 1991;Shinoda et al 1993;Gutekunst et al 1998).…”

Quantitative changes of Holmes positive nucleolus-like inclusion bodies in the mouse locus coeruleus under various experimental conditions.

“…Finally, in light of earlier reports showing that inclusion bodies are composed of proteins and RNA (GRILLO, 1970;SANTOLAYA, 1973;HINDELANG-GERTNER et al, 1974;TAKEUCHI and TAKEUCHI, 1982;KATOH and SHIMIZU, 1982b), several synthesizing inhibitors were administered in the present experiments in order to observe the resultant changes. When cycloheximide and puromycin are administered directly to the brain, they are said to inhibit protein synthesis markedly (FLEXNER and FLEXNER, 1966;BARONDES and COHEN, 1967).…”

“…Morphologically, these inclusion bodies consist of larger and smaller granules and filamentous substances, and the main components are reported to be composed of proteins and ribonucleic acid (RNA) (GRILLO, 1970;SANTOLAYA, 1973;HINDELANG-GERTNER et al, 1974;KATOH and SHIMIZU, 1982b;TAKEUCHI and TAKEUCHI, 1982). However, the light microscopic stainability, quantities, chemical characteristics and functional significance of the inclusion bodies have not yet been clarified.…”