Document Detail


mRNA and protein expression and activities of nitric oxide synthases in the lumbar spinal cord of neonatal rats after sciatic nerve transection and melatonin administration.
MedLine Citation:
PMID:  16978780     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Sciatic axotomy in 2-day-old rats (P2) causes lumbar motoneuron loss, which could be associated with nitric oxide (NO) production. NO may be produced by three isoforms of synthase (NOS): neuronal (nNOS), endothelial (eNOS) and inducible (iNOS). We investigated NOS expression and NO synthesis in the lumbar enlargement of rats after sciatic nerve transection at P2 and treatment with the antioxidant melatonin (sc; 1 mg/kg). At time points ranging from P2 to P7, expression of each isoform was assessed by RT-PCR and immunohistochemistry; catalytic rates of calcium-dependent (nNOS, eNOS) and independent (iNOS) NOS were measured by the conversion of [3H]L-arginine to [3H]L-citrulline. All NOS isoforms were expressed and active in unlesioned animals. nNOS and iNOS were detected in some small cells in the parenchyma. Only endothelial cells were positive for eNOS. No NOS isoform was detected in motoneurons. Axotomy did not change these immunohistochemical findings, nNOS and iNOS mRNA expression and calcium-independent activity at all survival times. However, sciatic nerve transection reduced eNOS mRNA levels at P7 and increased calcium-dependent activity at 1 and 6 h. Melatonin did not alter NOS expression. Despite having no action on NOS activity in unlesioned controls the neurohormone enhanced calcium-dependent activity at 1 and 72 h and reduced calcium-independent catalysis at 72 h in lesioned rats. These results suggest that NOS isoforms are constitutive in the neonatal lumbar enlargement and are not overexpressed after sciatic axotomy. Changes in NO synthesis induced by axotomy and melatonin administration in the current model are discussed considering some beneficial and deleterious effects that NO may have.
Authors:
Fábio Rogério; Simone Aparecida Teixeira; Hamilton Jordão Júnior; Carla Cristina Judice Maria; André Schwambach Vieira; Alexandre César Santos de Rezende; Gonçalo Amarante Guimarães Pereira; Marcelo Nicolás Muscará; Francesco Langone
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-09-15
Journal Detail:
Title:  Neuroscience letters     Volume:  407     ISSN:  0304-3940     ISO Abbreviation:  Neurosci. Lett.     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2006-09-25     Completed Date:  2006-11-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7600130     Medline TA:  Neurosci Lett     Country:  Ireland    
Other Details:
Languages:  eng     Pagination:  182-7     Citation Subset:  IM    
Affiliation:
Department of Physiology and Biophysics, State University of Campinas, UNICAMP, 13083-970 Campinas, SP, Brazil.
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MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Newborn / metabolism*
Axotomy
Immunohistochemistry
Melatonin / pharmacology*
Nerve Tissue Proteins / biosynthesis*
Nitric Oxide / physiology
Nitric Oxide Synthase Type I / metabolism*
RNA, Messenger / biosynthesis*
Rats
Rats, Wistar
Sciatic Nerve / metabolism*
Spinal Cord / enzymology,  metabolism*
Chemical
Reg. No./Substance:
0/Nerve Tissue Proteins; 0/RNA, Messenger; 10102-43-9/Nitric Oxide; 73-31-4/Melatonin; EC 1.14.13.39/Nitric Oxide Synthase Type I

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