Protein synthesis and release by normal and lesioned axolotl peripheral nerves.
(1995)
Journal - Experimental neurology (UNITED STATES )
Abstract :
Previous studies in urodeles (Holder et al., 1982, J. Physiol. 326:371; Holder et al., 1984, Proc. R. Soc. Lond. B 222:477; Aaronson et al., 1995, Neuroscience 66:201) have shown that regenerating axons of peripheral nerves tend to grow toward distal nerve stumps, which is consistent with the hypothesis that axonal growth may be stimulated by factors released from degenerating nerves. In the present study we used two-dimensional gel electrophoresis and autoradiography to compare the incorporation of radiolabeled methionine into proteins which are synthesized and released in vitro by segments of normal and previously cut axolotl sciatic nerves, within the isoelectric point range 2.4-10.6 and molecular weight range 3.6-200 kDa. In the distal portion of nerves cut 7 days previously in vivo, the synthesis of at least six secreted proteins was significantly greater than in undamaged nerves. The possible cellular sources of these proteins was assessed by comparing protein release from normal nerves with nerve segments maintained in culture for 7 days (in which the contribution from recruited macrophages would be expected to be minimal) and segments of nerve which had been frozen and then replaced in situ for 7 days (in which the contribution from sheath cells would be expected to be minimal).(ABSTRACT TRUNCATED AT 250 WORDS)
| ISSN : | 0014-4886 |
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| Mesh Heading : | Ambystoma mexicanum Animals Autoradiography Culture Techniques Electrophoresis, Gel, Two-Dimensional Heparin Immunologic Techniques Methionine Nerve Tissue Proteins Peripheral Nervous System Diseases Reference Values Sciatic Nerve metabolism metabolism cytology |
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| Mesh Heading Relevant : | metabolism metabolism metabolism |
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Expression of GAP-43 in normal and regenerating nerves in the frog.
(1993)
Journal - Neuroscience (ENGLAND )
Abstract :
A polyclonal antiserum to chicken, growth-associated protein-43 (GAP-43), raised in rabbit, was shown to recognize a molecule with similar properties to GAP-43 in frogs. Using this antiserum, GAP-43 immunoreactivity was shown to be present throughout the brain and white matter of the spinal cord of larval frogs, but became restricted to specific regions in the adult frog central nervous system. In the peripheral nervous system, GAP-43 was present in normal tadpole and adult axons. After cutting the adult sciatic nerve, GAP-43 slowly disappeared from axons in the distal stump, but appeared in Schwann cells and other (uncharacterized) cells. The constitutive expression of GAP-43 in the adult frog sciatic nerve may be related to the phenomenon of remodelling of motor end-plates, which is known to occur throughout life in frogs.
| ISSN : | 0306-4522 |
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| Mesh Heading : | Animals Antibodies Autoradiography Axonal Transport Axons Brain Brain Chemistry Electrophoresis, Polyacrylamide Gel GAP-43 Protein Immunoblotting Immunohistochemistry Larva Membrane Glycoproteins Motor Endplate Nerve Regeneration Nerve Tissue Proteins Nervous System Rana pipiens Rana temporaria Sciatic Nerve Spinal Cord analysis physiology growth & development physiology immunology chemistry immunology metabolism growth & development metabolism physiology metabolism |
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| Mesh Heading Relevant : | biosynthesis physiology biosynthesis metabolism |
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Effects of freezing a segment of peripheral nerve on subsequent protein release and axonal regeneration in the frog.
(1992)
Journal - Experimental neurology (UNITED STATES )
Abstract :
Previous studies in frogs have shown that axons from the proximal stump of a cut nerve will grow toward the distal stump, possibly in response to diffusible trophic factors produced by cells of the nerve sheath. In the present experiments, the synthesis and release of proteins in vitro, from proximal and distal stumps of frog sciatic nerves, were studied 1, 4, and 14 days after nerve section in vivo. Using two-dimensional gel electrophoresis to separate released proteins, a marked increase in the synthesis of two lipoproteins of 37 and 67 kDa was seen, initially in both proximal and distal stumps, but by 14 days these proteins were produced exclusively by the distal stump. To see if the production of these proteins was correlated with subsequent reinnervation of the distal stump, isolated nerve segments were removed from the frogs and either replaced immediately or frozen (to kill sheath cells) and replaced. After 2 weeks, the pattern of newly synthesized proteins released by both the frozen and nonfrozen nerve segments was similar although freezing severely impaired the reinnervation of the nerve segment. These results suggest that although the 37- and 67-kDa lipoproteins may have a role in nerve regeneration, their presence per se is not sufficient to support the reinnervation of a distal stump of a cut peripheral nerve and that additional factors may therefore be required.
| ISSN : | 0014-4886 |
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| Mesh Heading : | Animals Autoradiography Axons Denervation Densitometry Nerve Tissue Proteins Rana pipiens Sciatic Nerve Ultracentrifugation |
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| Mesh Heading Relevant : | Freezing Nerve Regeneration physiology metabolism metabolism |
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