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1996-03-04
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Document 0625
DOCN M9640625
TI Neurotoxic mechanisms of transactivating protein Tat of Maedi-Visna
virus.
DT 9604
AU Strijbos PJ; Zamani MR; Rothwell NJ; Arbuthnott G; Harkiss G; Department
of Molecular Pharmacology, Wellcome Research; Laboratories, Beckenham,
Kent, UK.
SO Neurosci Lett. 1995 Sep 15;197(3):215-8. Unique Identifier : AIDSLINE
MED/96117198
AB Infection by lentiviruses such as human immunodeficiency virus (HIV) and
Maedi-Visna virus (MVV) is associated with neurodegenerative disorders.
We have investigated the neurotoxic mechanisms of a synthetic peptide of
transactivating protein tat of MVV in striatal neuronal cultures. Tat
peptide (but not control peptide) caused neuronal death, without
affecting glial viability, in a time- and dose-dependent manner.
Significant neuronal death was not observed until 6-8 h after tat
peptide application (2.35-2350 nM), whereas half maximal and maximal
cell death was observed after 12 and 24 h respectively. Tat peptide
neurotoxicity could be partially inhibited by blockade of either
N-methyl-D-aspartate (NMDA)- or non-NMDA receptors, suggesting that
excessive neuroexcitation by glutamate or its analogues may contribute
to tat-neurotoxicity. Furthermore, when both these glutamate receptor
subtypes were blocked simultaneously, an increased degree of
neuroprotection was observed. Finally, tat peptide toxicity was also
reduced by blockade of L-type calcium channels. Calcium imaging revealed
that intracellular calcium increases slowly upon tat application,
predominantly due to entry of extracellular calcium. These results
indicate that cellular calcium entry through voltage-gated calcium
channels following activation of both NMDA and non-NMDA receptors, and
subsequent accumulation of intracellular calcium may contribute to the
neuronal death induced by tat protein.
DE Animal Calcium/METABOLISM Cell Death Cells, Cultured Corpus
Striatum/CYTOLOGY Dose-Response Relationship, Drug Gene Products,
tat/*PHARMACOLOGY Immunohistochemistry Nerve Degeneration
Neurons/DRUG EFFECTS/METABOLISM Neurotoxins/*PHARMACOLOGY Rats Rats,
Sprague-Dawley Support, Non-U.S. Gov't Time Factors *Visna-Maedi
Virus JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).