[Role of ryanodine receptors in hydrogen peroxide-induced DNA fragmentation and thymidine incorporation in cultured rat astrocytes].
In the CNS, reactive oxygen species (ROS) have been implicated in a wide range of degenerative processes including amyotrophic lateral sclerosis, ischemia-reperfusion injury, Alzheimer disease, Parkinson disease and aging. However, the exact mechanism is unknown, and there is little information on possible roles of ROS in cell injury and the process on recovery of astrocytes, the most abundant glial cells in the brain. We examined hydrogen peroxide (H2O2)-induced DNA fragmentation and thymidine incorporation into cultured astrocytes as an indicator of the process of recovery from astrocytic DNA injury. Astrocytes were isolated from cerebral cortices of 0-day-old rats and treated with 1 mM dibutyryl cyclic AMP for 4 days. H2O2 of 100 microM stimulated thymidine incorporation into astrocytes. Caffeine, ryanodine, cyclic ADP-ribose (endogenous ryanodine receptor agonist) and beta-NAD+ (precursor of cyclic ADP-ribose) suppressed partially the stimulatory effect of H2O2. Ruthenium red (ryanodine receptor antagonist) facilitated further the stimulatory effect of H2O2. The facilitated effect of ruthenium red on H2O2-induced thymidine incorporation was suppressed by caffeine, ryanodine, cyclic ADP-ribose and beta-NAD+. H2O2-induced DNA fragmentation and astrocytic death were suppressed by ruthenium red. These findings suggest that the process of recovery from astrocytic DNA injury by H2O2 may be regulated by Ca2+ efflux from ryanodine-sensitive intracellular Ca2+ stores.
Tanaka
K
K
Department of Parmacology Kagoshima University Dental School, Japan.
Ohnishi
Y
Y
Sato
T
T
Nishikawa
T
T
D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D016923:Cell Death / Q000502:physiology; D002478:Cells, Cultured; D036563:Cyclic ADP-Ribose; D053938:DNA Fragmentation / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012430:Ruthenium Red / Q000494:pharmacology; D012433:Ryanodine / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000502:physiology*; D013936:Thymidine / Q000378:metabolism*
D019837:Ryanodine Receptor Calcium Release Channel; D012430:Ruthenium Red; D036563:Cyclic ADP-Ribose; D012433:Ryanodine; D000246:Adenosine Diphosphate Ribose; D002110:Caffeine; D006861:Hydrogen Peroxide; D002118:Calcium; D013936:Thymidine