Showing papers on "Nervous system published in 1981"

Axonal elongation into peripheral nervous system "bridges" after central nervous system injury in adult rats

Abstract: The origin, termination, and length of axonal growth after focal central nervous system injury was examined in adult rats by means of a new experimental model. When peripheral nerve segments were used as "bridges" between the medulla and spinal cord, axons from neurons at both these levels grew approximately 30 millimeters. The regenerative potential of these central neurons seems to be expressed when the central nervous system glial environment is changed to that of the peripheral nervous system.

Immunochemical and immuno-cytochemical localization of S-100 antigen in normal human skin.

Abstract: The S-100 antigen1 is generally considered to be unique to the nervous system, where it is found primarily in the cytoplasm and nucleus of glial cells, both in soluble and bound form2,3. It belongs to the family of acidic Ca2+-binding proteins4. In phylogenesis, S-100 conserves a close immunological relationship between different species, and during ontogenesis the pattern of its accumulation parallels the functional maturation of the nervous system2,3, although its biological role remains to be clarified. Recently, S-100 has been found in cells of non-nervous organs (interstitial cells of the pineal gland5, stellate cells of the adenohypophysis6,7 and satellite cells of the adrenal medulla8), and in cultured malignant human melanomas9. We report here the presence of S-100 in normal human skin, where the antigen seems to be located specifically in melanocytes and in cells with morphological features of Langerhans cells.

Differential effects of capsaicin on the content of somatostatin, substance P, and neurotensin in the nervous system of the rat.

Abstract: The distribution of immunoreactive substance P (I-SP), somatostatin (I-SRIF), and neurotensin (I-NT) and the effect of capsaicin treatment on the concentration of these peptides was studied in the peripheral and central nervous system of the rat. Neonatal capsaicin treatment (50 mg/kg s.c.) caused a depletion of I-SRIF as well as of I-SP in sensory nerves and in the dorsal half of the spinal cord. No recovery of the peptide content was found when examined 4 months later suggesting an irrerersible effect. I-NT, not a constituent of primary sensory neurons, was not changed in the spinal cord. None of the peptides studied was depleted in the hypothalamus or preoptic area. Capsaicin treatment of adult rats also led to a decrease of I-SRIF and I-SP in primarh sensory neurons. The highest dose used (950 mg/kg s.c.) induced no greater depletion than the lowest one (50 mg/kg), except for I-SP in dorsal root ganglia. Intraperitoneal injection of capsaicin led to a higher degree of depletion than subcutaneous administration as examined 1 week after treatment. In contrast to neonatal treatment, the I-SRIF content was completely restored within 4 months after treatment of adult rats. The I-SP content, however, did not completely recover in all areas but remained reduced in cornea, vagus nerve, dorsal spinal cord, and medulla oblongata for up to 9 months. Intraventricular administration of capsaicin (200 μg) caused a depletion of I-SP in the medulla oblongata but had no effect on the content of all 3 peptides in hypothalamus or preoptic area. In contrast to systemic treatment, no depletion of I-SP or I-SRIF was found in the trigeminal ganglion. Chemosensitivity of the eye was abolished after intraventricular or systemic treatment. Repeated topical application of a capsaicin solution (10 mg/ml) to the eye led within 4 h to a nearly complete depletion of I-SP in the cornea. These experiments show that capsaicin treatment of rats caused a depletion of both I-SRIF and I-SP in primary sensory neurons. While topical or systemic capsaicin administration causes depletion in terminals, the failure of intraventricular injections of capsaicin to deplete the peptides in the trigeminal ganglion suggests that depletion of the entire neuron requires an action of capsaicin on the peripheral branch and/or the cell body.

Glycine receptor: light microscopic autoradiographic localization with [3H]strychnine

Abstract: Glycine receptors have been localized by autoradiography in the rat central nervous system (CNS) using [3H]strychnine. The gross distribution of receptors is in excellent accord with the distribution determined by filtration binding assays. Specifically, the density of glycine receptors is greatest in the gray matter of the spinal cord and decreases progressively in regions more rostral in the neuraxis. Glycine receptors were found to be associated with both sensory and motor systems in the CNS. Moreover, there is a striking correlation between areas of high strychnine binding site density and areas in which glycine has been found to be electrophysiologically active. Finally, the anatomic localization of strychnine binding sites may help explain many of the signs and symptoms of strychnine ingestion. For example, individuals consuming subconvulsive doses of strychnine frequently experience altered cutaneous and auditory sensation. We have localized strychnine receptors in areas of the acoustic system known to influence discriminative aspects of audition and in areas of the spinal cord and trigeminal nuclei which modulate discriminative aspects of cutaneous sensation. The alteration of visceral functions (e.g., blood pressure and respiratory rate) associated with strychnine ingestion may be accounted for in a similar manner.

Embryogenesis of an insect nervous system II: a second class of neuron precursor cells and the origin of the intersegmental connectives.

Abstract: The intersegmental connectives in the locust central nervous system are initiated by the axons of early differentiating neuron trios. Using a combination of electron microscopy and fluorescent dye injection we have shown that the axons of these cells grow out anteriorly and posteriorly in each segment along a basement membrane, and link together at the segment borders to form continuous longitudinal pathways on each side of the developing nervous system. These early neurons are the progeny of a second class of precursor cell, the midline precursors, which are distinct from the segmental neuroblasts. Like the neuroblasts, the midline precursors are arranged in a standard segmentally repeated pattern. This and the standard pattern of axon outgrowth in different segments suggest that the nervous system develops to a common, segmentally repeated programme.

Progressive neuropathologic lesions in vitamin E-deficient rhesus monkeys.

Abstract: A consistent group of progressive central and peripheral nervous system lesions developed in seven rhesus monkeys maintained on a vitamin E-deficient diet for 30 to 33 months. These lesions were absent from vitamin E-supplemented monkeys. The principal neuropathologic alteration was loss of sensory axons in the posterior columns, sensory roots, and peripheral nerves. Morphologic and morphometric studies indicated that the distal segments of the axons were affected most severely and large-caliber myelinated fibers are selectively involved. Swollen, dystrophic axons (spheroids) occurred infrequently. Degeneration and phagocytosis of small numbers of neuronal perikarya were observed in the dorsal root ganglia and the anterior horns. The number of affected neurons was not proportional to the number of affected axons. Accumulation of lipopigment was evident in neuronal perikarya and CNS endothelial cells. The nervous system lesions were usually accompanied by a chronic necrotizing myopathy. The neuropathologic lesions in vitamin E-deficient monkeys are compared with those in vitamin E-deficient rats and in humans with low serum vitamin E concentrations. A similar type of sensory axonopathy is associated with chronic deficiency of vitamin E in these three species.

Decreased glutamate uptake in subcortical areas deafferented by sensorimotor cortical ablation in the cat

Abstract: Evidence that L-glutamate is a neurotransmitter of corticofugal fibers was sought by measuring changes in several biochemical markers of neurotransmitter function after pericruciate (sensorimotor) ablations in cats. Two weeks after cortical ablation, samples from various brain regions were analyzed for high affinity uptake of glutamate, gama- aminobutyric acid (GABA), glycine, alanine, and tyrosine. Amino acid levels and the activity of choline acetyltransferase (CAT) also were determined. High affinity glutamate uptake is decreased relative to the opposite side in areas of the nervous system which lost a predominantly unilateral corticofugal projection. These areas include the caudate nucleus, ventrolateral thalamic nucleus, red nucleus, basis pontis, and cervical and lumbar spinal cord. No significant changes were found in the uptake of other amino acids or in CAT in these regions. Changes in the levels of amino acids were significant only in ventrolateral thalamus where there was a 33% decrease in glutamate on the deafferented side. The data suggest that L-glutamate is a neurotransmitter of corticofugal fibers to many subcortical areas related to motor control.

Radiation Damage to the Nervous System

Abstract: This book is greatly needed in the fields of oncology, neuro-oncology, and clinical neurology. Its first three chapters deal with delayed necrosis in the monkey brain, clinical features of irradiation injury of the human brain, and dosimetric considerations. Next are discussions of neurological and neuropathological perspectives of CNS radionecrosis, its treatment, and the use of imaging techniques in its diagnosis. Specific types of radiation damage are covered in chapters on radiation injury of the cranial and peripheral nerves and the hypothalamic pituitary regions. Spinal-cord injury and the relative radiation tolerance of brain and spinal cord are covered in two chapters. The last chapter is devoted to a comparison of myelopathy associated with megavoltage irradiation and remote cancers. Although rare, the consequences of radiation injury to the nervous system are serious. The book is of manageable length and provides a good discussion of nervous system radiation injury. The reader is given

Experimental diabetic autonomic neuropathy.

Abstract: The regular occurrence of autonomic neuropathy, colonic dilatation, and loss of fecal consistency was investigated in streptozotocin-diabetic, age-matched control, and pancreatic-islet--transplanted rats using ultrastructural, histochemical, and biochemical methods. Degenerating unmyelinated axons were observed by electron microscopy in the colonic submucosa and muscularis, ileal mesentery, and splenic pedicle in 5--7 months diabetic animals; similar changes were not found in control rats or animals subjected to islet transplantation three weeks after induction of diabetes and sacrificed 4--6 months later (colon only). Regenerative changes, including axons with identifiable growth cones, were demonstrated in the mesenteric nerves of chronically diabetic animals. Formaldehyde-induced catecholamine fluorescence and cholinesterase histochemistry suggested deficiencies in colonic adrenergic and cholinergic innervation; histochemical findings in islet-transplanted animals were comparable to those of untreated control animals. Biochemical measurements of the adrenergic and cholinergic nervous system marker enzymes dopamine-beta-hydroxylase and choline acetyltransferase, respectively, in colon and spleen confirm a deficit in adrenergic (colon and spleen) and cholinergic (colon) innervation in chronically diabetic animals.

Cell-surface antigen distinguishes sensory and autonomic peripheral neurones from central neurones.

Abstract: Cell-surface markers are useful in identifying and studying different cell types in the nervous system. For example, the major cell types in rat dorsal root ganglion (DRG) cultures have been identified using a combination of tetanus toxin and antibodies to the cell-surface antigens Ran-1 and Thy-1. Neurones bind tetanus toxin and express Thy-1, Schwann cells express only Ran-1 and fibroblasts express only Thy-1 (ref. 1). A natural extension of this approach was to use antibodies to distinguish between different neuronal subpopulations on the basis of their cell-surface antigens. We therefore immunized mice with cells from rat DRG cultures, and then used the hybridoma technique of Kohler and Milstein2 to produce monoclonal antibodies. We report here an antibody that recognizes a surface antigen which is present on all rat peripheral neurones we have studied and absent from neurones derived from the central nervous system. An antigen with reciprocal distribution, expressed only by neurones of the rat central nervous system, has been defined by Cohen and Selvendran3.

A neuronal cell-surface antigen is found in the CNS but not in peripheral neurones.

Abstract: In embryogenesis, the neural tube gives rise to the neurones of the central nervous system (CNS) whereas those in the peripheral nervous system (PNS) are generated from the neural crest and possibly also the placodes. Little is known of the part played by cell-surface molecules in this early sorting-out process and in subsequent interactions between different classes of neurone during development. Of the few known antisera that seem to define neuronal cell-surface antigens, none appears to distinguish between neuronal subpopulations1–4. However, the discriminating power of the immunological approach to this question has been greatly enhanced by the advent of the hybridoma technique for making monoclonal antibodies5–8. We have produced a hybridoma secreting an antibody that binds to the surfaces of neurones from the CNS but not from the PNS. The accompanying letter describes a monoclonal antibody with the reciprocal neuronal distribution9.

Effects of chronic vitamin E deficiency on the nervous system of the rat

Abstract: Light- and electron-microscopic studies were carried out on the central nervous system (CNS) and the peripheral nervous system (PNS) of vitamin E-deficient rats. Extensive axonal degeneration and dystrophic changes were observed in posterior columns and their medullary relay nuclei, respectively. The changes were more prominent in gracile tracts and nuclei than cuneate tracts and nuclei. Alteration in the PNS were less severe than those in the CNS. The posterior roots and sciatic nerves showed only a mild degree of axonal degeneration, while more distal segments of axons in s.c. nerves, in cutaneous sensory corpuscles, and in muscle spindles of hind paws were more severely affected. The neurons in the dorsal root ganglia showed only accumulation of lipofuscin. The above findings in chronic vitamin E deficiency indicate that (a) in addition to the degeneration of central extensions of sensory neurons, their peripheral axons are also affected, (b) the distribution of lesions is similar to those seen in distal axonopathies or a “dying back” process.

The Relationship between Function and Energy Metabolism: Its Use in the Localization of Functional Activity in the Nervous System

Abstract: A published version of Sokoloff's F. O. Schmitt Lecture in Neuroscience, given at MIT, March 18, 1980, on receiving the F. O. Schmitt Prize

Transitions in the Nervous System during Amphibian Metamorphosis

Abstract: The tadpole as a whole can be considered to be an aggregate of mosaic territories, each responding in a distinctive way to the increased titers of thyroid hormones (TH) responsible for progressive metamorphic changes. Similarly, the separate elements of the nervous system can be considered, at least as a first approximation, to be composed of a series of mosaic territories. They differ as to the stages when they are first morphologically distinguishable, when they first acquire capacity to respond to TH, in the rates of increase in such sensitivity, i.e., in reduction of threshold concentrations required to elicit detectable change, and in the rates of response to given concentrations. They probably also differ with respect to the hormone concentrations required to elicit maximal rates of tissue response. Some elements of the nervous system grow and differentiate; others shrink, die, and disappear. The extent to which there may be elements of the nervous system that are unresponsive to TH remains largely to be established.

Anatomical Distribution of Phenolic and Tyrosyl Ring Iodothyronine Deiodinases in the Nervous System of Normal and Hypothyroid Rats

Abstract: We have evaluated regional differences in T4 5′-deiodinase and iodothyronine tyrosyl ring deiodinase activities and assessed the effect of hypothyroidism on these activities in the rat nervous system. T4 5′-deiodination and T3 tyrosyl ring deiodination were both measured by radiometric assays at 37 C in the presence of 100 mM dithiothreitol in homogenates of cerebral cortex, corpus striatum, midbrain, hypothalamus, cerebellum, brain stem, spinal cord, brachial plexus, and sciatic nerve from normal and hypothyroid rats. T4 5′-deiodinase activity was present throughout the central nervous system. In both groups, the highest mean reaction rates were in cerebral cortical and cerebellar homogenates. The lowest mean rate in normal rats was in spinal cord homogenates, and the lowest mean rate in the hypothyroid rats was in hypothalamic homogenates, with spinal cord being the next lowest. In each central nervous system region, T4 5′-deiodination rates were significantly higher in hypothyroid tissue than in normal...

Immunohistochemistry and Immunocytochemistry of Nervous Tissue

Abstract: During the last decade immunocytochemistry has become one of the most powerful tools for localizing specific substances in the nervous system. The method is based on investigations of Coons et al. (1955), Coons (1978) and of Sternberger (1969). Labeled antibodies directed against purified tissue components or substances are used on tissue sections for localization of their binding sites. This technique may be applied for multiple purposes: at the light and electron microscopical level functional systems of the central or peripheral nervous system can be explored, specific metabolic pathways may be analyzed, and pathologic states of nervous tissue may be recognized. Metabolites, enzymes, neurotransmitters, or receptor systems can be localized in the nervous tissue. Thus specific neuronal pathways, functional systems, and metabolic features of the nervous system are revealed at the macro-, micro-, and molecular-morphological level. Considering morphology as an important tool of understanding living processes and pathologic alterations, the basic importance of immunocytochemistry becomes evident, particularly for neuroanatomy. Almost no technique of comparable importance has been developed in the past decade for neuroanatomic studies.

Techniques in neuroanatomical research

Abstract: I General Research Methods in Neuroanatomy.- 1 General Methods in Light Microscopy of the Nervous System.- 2 General Methods in Transmission Electron Microscopy of the Nervous System..- 3 Freeze-Etching in Neuroanatomy..- 4 General Methods in Scanning Electron Microscopy of the Nervous System.- 5 Lesion Methods in Neurobiology..- 6 General Methods for Characterization of Brain Regions..- II Light Microscopical Research Methods in Neuroanatomy.- 7 Enzyme Histochemistry of Nervous Tissue..- 8 The Golgi Methods..- 9 Fluorescence Histochemistry of Biogenic Monoamines..- 10 Immunohistochemistry and Immunocytochemistry of Nervous Tissue..- 11 Identification of Single Neurons by Intracellular Application of Tracers..- 12 Light Microscopical Autoradiography of Nervous Tissue..- 13 Brain Localization of Hormones and Drugs by Thaw-mount Autoradiography, Combined Autoradiography-Formaldehyde Induced Fluorescence, and Combined Autoradiography-Immunohistochemistry..- 14 Combined Immunocytochemistry and Autoradiography: In Vivo Injections of Monoclonal Antibodies and Radioactive Amines (Substance P and 3H-Serotonin).- III Electron Microscopical Research Methods in Neuroanatomy.- 15 Quick-Freezing Methods in Neuroanatomy..- 16 Ultrastructural Histochemistry of Nervous Tissue..- 17 The Zinc Iodide-Osmium Tetroxide (ZIO) Method..- 18 Combined Freeze-Fracturing and Autoradiography Techniques: Freeze-Fracture Autoradiography..- IV Investigation of Living Nervous Tissue.- 19 Extracellular Marking and Retrograde Labelling of Neurons..- 20 Cell, Tissue, and Organ Culture in Neuroanatomy..

Nerve Cells in Clonal Systems

Abstract: A piece of neuronal tube from a frog embryo successfully grown by Harrison (1907) in a drop of clotted lymph was the first “tissue culture” of a nerve cell in vitro. Since then, the art of culturing cells for extended periods of time in defined media has been constantly improved and refined. Consequently, the neurobiologist has been provided with the opportunity to study the development of nervous tissue cells and their interactions with other cells under relatively controlled conditions. Primary cultures of brain cells (amphibian, avian, and mammalian) grown as monolayers or rotating aggregates, explants and single cell cultures from the spinal cord, sympathetic and sensory ganglia, and mixed cultures of nerve and muscle cells have all yielded a large, invaluable volume of information concerning the steps that lead to establishing the neuronal network. However, the complexity of the nervous system and the consequent difficulty of separating homogeneous populations of living neurons from their associated satellite cells make the biochemical studies of differentiation a formidable task. The long quest for a simpler system that exhibits neuronal properties and could still be manipulated under experimental conditions was partially satisfied with the establishment of continuous cell cultures derived from neuronal tumors.

Influence of nerve activity of the macromolecular content of neurons and their effector organs.

Abstract: The term "plasticity" is sometimes used to refer exclusively to anatomical changes in the nervous system that occur, in response either to neural damage or to changes in an animal's environment. However, in a more general sense, the term can encompass long-term changes in the biochemi­ cal and electrophysiological properties of neurons that occur under these same circumstances. One experimental approach to the study of biochemi­ cal plasticity has been to ask what effects periods of "use" or "disuse" have on the biochemistry of neurons and their effector cells. Biochemical changes following repeated activation of a neural circuit have often been postulated to underlie long-term changes in an animal's behavior and physiology (e.g. learning, adaptation to environmental change) (see 44). Such activity­ dependent changes have thus far been most successfully studied in the peripheral nervous system-particularly in skeletal muscle, the superior cervical ganglion, and the pineal gland. This brief review summarizes evi­ dence that the level of neural stimulation of these tissues affects the concen­ trations of certain proteins important in regulating the tissues' function.