CA2-DEPENDENT MECHANISMS OF CELL INJURY IN CULTURED CORTICAL-NEURONS()

Citation
Mr. Castillo et Jr. Babson, CA2-DEPENDENT MECHANISMS OF CELL INJURY IN CULTURED CORTICAL-NEURONS(), Neuroscience, 86(4), 1998, pp. 1133-1144
Citations number
48
Categorie Soggetti
Neurosciences
Journal title
ISSN journal
03064522
Volume
86
Issue
4
Year of publication
1998
Pages
1133 - 1144
Database
ISI
SICI code
0306-4522(1998)86:4<1133:CMOCII>2.0.ZU;2-C
Abstract
The contributions of several Ca2+-dependent processes to neurotoxicity were examined in primary cultures of rat cortical neurons. The Ca2+ i onophore ionomycin induced a rapid loss of axonal morphology and conco mitant release of inositol phosphates that preceded morphological alte rations of neuronal cell bodies, choline and arachidonate release, and protein degradation. These events were followed by a degree of neuron al lysis proportional to the external Ca2+ concentration and exposure time. The phospholipase inhibitor neomycin decreased both arachidonate release and the phospholipid hydrolysis catalysed by phospholipases C and D. Proteolysis was abated by the protease inhibitor leupeptin, bu t not by lysosomal proteolysis inhibitors. Neuronal lysis was inhibite d partially by either leupeptin or neomycin and almost completely by b oth in combination. However, neither agent, alone or in combination, a ffected the morphological derangements. The diacylglycerol lipase inhi bitor RHC-80267 reduced arachidonate release, but not neuronal lysis. Phospholipase A(2) inhibitors had no effect on either arachidonate rel ease or lysis. Treatment of mixed cultures of neurons and glia with a Ca2+-dependent glutamate challenge caused similar morphological change s and a delayed neuronal lysis that was also diminished by leupeptin a nd neomycin, but not by inhibitors of lysosomal proteolysis. These dat a describe several distinct stages of Ca2+-dependent injury to cortica l neurons, a key feature of which is the stimulation of protease, and phospholipase C and D activities. The initial stage is characterized b y a rapid loss of axonal morphology and increased phosphatidylinositol hydrolysis. An intermediate stage involves changes in cell body morph ology plus the degradation of neuronal protein and phosphatidylcholine . In a later stage, the loss of plasma membrane integrity denotes neur onal death. (C) 1998 IBRO. Published by Elsevier Science Ltd.