Document Detail


At least two mechanisms are involved in the death of retinal ganglion cells following target ablation in neonatal rats.
MedLine Citation:
PMID:  8613749     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Removal of the superior colliculus (SC) in neonatal Wistar rats results in a rapid loss of retinal ganglion cells (RGCs). There is an early twofold increase in RGC death 4-8 hr postlesion (PL) followed by a later 10-11-fold increase in pyknosis about 24 hr PL. We have now used neurotrophic factors (BDNF, NT-4/5, NT-3, NGF, LIF), glutamate receptor antagonists (MK-801, DNQX, CNQX), an antioxidant (N-ace-tyl-L-cysteine), and an NOS inhibitor (L-NAME) to determine whether the early and late phases of lesion-induced RGC death involved similar or different mechanisms. Normal and pyknotic nuclei of tectally projecting RGCs were visualized by injecting the left s.c. of 2 d old rats with diamidino yellow (DY). Two days later the injection site was removed. In most rats, right eyes were injected with factors immediately after the s.c. ablation. Rats were perfused either 6 or 24 hr PL. In the latter group a second intravitreal injection of the appropriate factor was sometimes made 12 hr PL. NT- 4/5 and BDNF significantly decreased RGC pyknosis 6 and 24 hr PL, whereas NT-3 was only protective 6 hr PL. LIF slightly reduced RGC death 24 hr PL, but NGF had no influence on RGC survival at either time point. NT-4/5 also reduced the rate of naturally occurring RGC death. MK-801, DNQX, CNQX, N-acetylcysteine, and L-NAME all prevented the early lesion-induced increase in RGC death but had no significant effect on RGC death measured 24 hr PL; none of these factors significantly reduced the rate of naturally occuring RGC death. Cycloheximide, shown previously to reduce RGC pyknosis 24 hr PL, did not prevent RGC death 6 hr PL. The data indicate that there are at least two mechanisms involved in RGC death after neonatal target ablation. The early increase is related to excitotoxic effects mediated by glutamate receptors and involves NOS and the production of free radicals. We found no evidence that RGC death measured 24 hr PL is dependent on these processes, but the later death does require protein synthesis and, most likely, the activation of an endogenous suicide program. NT-4/5 and BDNF protected RGCs from both types of lesion-induced death.
Authors:
Q Cui; A R Harvey
Related Documents :
25431309 - Hospitalisation costs for infant bronchiolitis are up to 20 times higher if intensive c...
21469459 - Infant feeding and hiv positive mothers in the capricorn district of limpopo province.
16840509 - Climate impacts on myocardial infarction deaths in the athens territory: the climate st...
760509 - Infantile atlantooccipital instability. the potential danger of extreme extension.
12608629 - An investigative report on circumstances leading to death among indian cotton farmers.
7572879 - Unexpected infant death in association with suspended rocking cradles.
23724829 - An hour-specific nomogram for transcutaneous bilirubin values in japanese neonates.
15738019 - The impact of vaginal delivery in premature infants weighing less than 1,251 grams.
14149409 - Serotonin deficiency in infancy as one cause of a mental defect in phenylketonuria.
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  15     ISSN:  0270-6474     ISO Abbreviation:  J. Neurosci.     Publication Date:  1995 Dec 
Date Detail:
Created Date:  1996-06-06     Completed Date:  1996-06-06     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  8143-55     Citation Subset:  IM    
Affiliation:
Department of Anatomy and Human Biology, University of Western Australia, Nedlands, Perth, Australia.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Newborn / physiology*
Antioxidants / pharmacology
Biomechanics
Cell Count
Cell Death
Denervation
Excitatory Amino Acid Antagonists / pharmacology
Nerve Growth Factors / pharmacology
Nitric Oxide Synthase / antagonists & inhibitors
Rats
Rats, Wistar
Retinal Ganglion Cells / cytology,  drug effects,  physiology*
Superior Colliculi / physiology*
Time Factors
Chemical
Reg. No./Substance:
0/Antioxidants; 0/Excitatory Amino Acid Antagonists; 0/Nerve Growth Factors; EC 1.14.13.39/Nitric Oxide Synthase

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


Previous Document:  Nerve growth factor facilitates cholinergic neurotransmission between nucleus basalis and the amygda...
Next Document:  Expression of mu-, delta-, and kappa-opioid receptor-like immunoreactivities in rat dorsal root gang...