Document Detail


Progressive changes in synaptic inputs to motoneurons in adult sacral spinal cord of a mouse model of amyotrophic lateral sclerosis.
MedLine Citation:
PMID:  19955354     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Amyotrophic lateral sclerosis (ALS) is characterized by progressive degeneration of motoneurons. One potential mechanism is excitotoxicity. We studied the behaviors of spinal neurons using an in vitro preparation of the sacral cord from the G93A SOD1 mouse model of ALS. Measurements were conducted at presymptomatic [approximately postnatal day 50 (approximately P50)], early (approximately P90), and late (>P120) stages of the disease. Short-latency reflexes (SRs) in ventral roots, presumably monosynaptic, were evoked by electrical stimulation of a dorsal root. The fraction of motoneurons capable of responding to this activation was evaluated by measuring the compound action potential [total motor activity (TMA)] evoked by antidromic stimulation of the distal ventral root. In mutant SOD1 (mSOD1) mice, both the SR and the TMA decreased with age compared with nontransgenic littermates, ruling out the SR as a source of increasing excitotoxicity. Spinal interneuron activity was assessed using the synchronized ventral root bursts generated by both bath application of blockers of inhibitory neurotransmitters (glycine, GABA(A)) and agonists of glutamate receptors (especially NMDA receptors). After symptom onset, a higher percentage of preparations from mSOD1 mice exhibited bursting, and these bursts exhibited more sub-bursts and a more disorganized pattern. In mSOD1 mice with clear muscle tremor, the ventral roots exhibited spontaneous synchronized bursts, which were highly sensitive to the blockade of NMDA receptors. These data suggest that although short-latency sensory input does not increase as symptoms develop, interneuron activity does increase and may contribute to excitotoxicity.
Authors:
Mingchen Jiang; Jenna E Schuster; Ronggen Fu; Teepu Siddique; C J Heckman
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  29     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2009 Dec 
Date Detail:
Created Date:  2009-12-03     Completed Date:  2009-12-22     Revised Date:  2011-09-26    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  15031-8     Citation Subset:  IM    
Affiliation:
Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA. m-jiang@northwestern.edu
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / drug effects,  physiology
Age Factors
Amyotrophic Lateral Sclerosis / genetics,  pathology*,  physiopathology
Animals
Biophysics / methods
Chi-Square Distribution
Disease Models, Animal
Disease Progression
Electric Stimulation
Excitatory Amino Acid Agonists / pharmacology
Excitatory Amino Acid Antagonists / pharmacology
Humans
Interneurons / physiology
Mice
Mice, Transgenic
Motor Neurons / pathology*,  physiology*
Mutation
N-Methylaspartate / pharmacology
Patch-Clamp Techniques / methods
Psychomotor Performance / drug effects,  physiology
Quinoxalines / pharmacology
Reaction Time / genetics
Reflex / drug effects,  genetics,  physiology
Spinal Cord / pathology*
Superoxide Dismutase / genetics
Synapses / pathology,  physiology*
Grant Support
ID/Acronym/Agency:
F31 NS060532-02/NS/NINDS NIH HHS; NS050641/NS/NINDS NIH HHS; NS051462/NS/NINDS NIH HHS; R01 NS050641-04/NS/NINDS NIH HHS; R01 NS051462-04/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
0/Excitatory Amino Acid Agonists; 0/Excitatory Amino Acid Antagonists; 0/Quinoxalines; 2379-57-9/FG 9041; 6384-92-5/N-Methylaspartate; EC 1.15.1.-/superoxide dismutase 1; EC 1.15.1.1/Superoxide Dismutase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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