Biomaterial Database

Patterns of degeneration in the external cuneate nucleus after multiple dorsal rhizotomies. 1977

J M Rosenstein, and R B Page, and A E Leure-DuPree

Unilateral, intradural dorsal rhizotomies (C3-Cs) were performed on adult rats to study the patterns of synaptic organization of ascending dorsal root fibers in the external cuneate nucleus (ECN). Animals were permitted to survive for periods of time ranging from 3 hours to 12 days. Sham-operated animals presented a morphology indistinguishable from that of normal, unoperated animals. In rhizotomized animals, degeneration was observed ipsilaterally at all survival periods. After postoperative survivals of 3 to 14 hours some terminal boutons displayed clumping and diminution in numbers of synaptic vesicles and, in addition, degeneration myelinated axons were observed at this time. There was considerable degeneration in the neuropil between 24 and 48 hours postoperative. Two forms of degeneration occurred in axons and terminal boutons with comparable frequency: electron lucent degeneration and electron opaque degeneration. Reactive phagocytic glial cells contained degenerated masses, lipoid droplets, lysosome-like structures and myelin fragments. After postoperative survivals of four to six days, lucent and opaque degenerating terminals were less numerous. Neurofilamentous degeneration was observed only occasionally. Unaltered synaptic membrane specializations were present and were usually abutted by glia. At 12 days postoperative, synaptic glomeruli and serial synapses were not seen. Invaginating dendritic spines were rarely seen. Bouton populations that remained unualtered were: small (0.3-3.0 micron) boutons that contact dendritic shafts and somata, nodal synaptic boutons and boutons containing granular vesicles (80-100 nm).

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008526	Medulla Oblongata	The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.	Accessory Cuneate Nucleus,Ambiguous Nucleus,Arcuate Nucleus of the Medulla,Arcuate Nucleus-1,External Cuneate Nucleus,Lateral Cuneate Nucleus,Nucleus Ambiguus,Ambiguus, Nucleus,Arcuate Nucleus 1,Arcuate Nucleus-1s,Cuneate Nucleus, Accessory,Cuneate Nucleus, External,Cuneate Nucleus, Lateral,Medulla Oblongatas,Nucleus, Accessory Cuneate,Nucleus, Ambiguous,Nucleus, External Cuneate,Nucleus, Lateral Cuneate
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009434	Neural Pathways	Neural tracts connecting one part of the nervous system with another.	Neural Interconnections,Interconnection, Neural,Interconnections, Neural,Neural Interconnection,Neural Pathway,Pathway, Neural,Pathways, Neural
D001931	Brain Mapping	Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.	Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013126	Spinal Nerve Roots	Paired bundles of NERVE FIBERS entering and leaving the SPINAL CORD at each segment. The dorsal and ventral nerve roots join to form the mixed segmental spinal nerves. The dorsal roots are generally afferent, formed by the central projections of the spinal (dorsal root) ganglia sensory cells, and the ventral roots are efferent, comprising the axons of spinal motor and PREGANGLIONIC AUTONOMIC FIBERS.	Dorsal Roots,Spinal Roots,Ventral Roots,Dorsal Root,Nerve Root, Spinal,Nerve Roots, Spinal,Root, Dorsal,Root, Spinal,Root, Spinal Nerve,Root, Ventral,Roots, Dorsal,Roots, Spinal,Roots, Spinal Nerve,Roots, Ventral,Spinal Nerve Root,Spinal Root,Ventral Root
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus