On the role of intracellular concentration of Ca2+ and H+ in thymocyte death after irradiation.
The role of intracellular Ca2+ and H+ concentrations in radiation-induced interphase death of rat thymocytes has been studied. In response to concanavalin A treatment in the Ca(2+)-containing medium, or to the CaCl2 treatment in the Ca(2+)-free medium, the [Ca2+]i rise in irradiated cells was as in the non-treated cells. No changes in the level of [Ca2+]i and pHi were found within 1 h after irradiation of thymocytes with a dose of 6 Gy. 15 microM 5-(N-ethyl-N-isopropyl)-amiloride, an inhibitor of Na+/H+ exchange, did not affect the DNA fragmentation. The fragmentation was prevented by 2-4 microM (1-[bis(4-chlorophenyl)methyl]-3-[2-(2,4-dichlorophenyl)]-2-[(2,4- dichlorophenyl)-methoxy]-ethyl)-1-H-imidazolium chloride, an inhibitor of calmodulin. The above data indicate that triggering of interphase death in irradiated thymocytes is not mediated by changes in either [Ca2+]i or pHi. Such changes seem to be involved in intermediate steps of the interphase death process.
Shaposhnikova
V V
VV
Laboratory of Cell Radiobiology, Russian Academy of Sciences, Pushchino, Moscow Region.
Dobrovinskaya
O R
OR
Gukovskaya
A S
AS
Trepakova
E S
ES
Korystov
Y N
YN
D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D017920:Antiporters / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000037:antagonists & inhibitors; D016923:Cell Death; D003208:Concanavalin A / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D011833:Radiation Injuries, Experimental / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013950:Thymus Gland / Q000166:cytology / Q000528:radiation effects*; D013997:Time Factors
D017920:Antiporters; D002147:Calmodulin; D007093:Imidazoles; D003208:Concanavalin A; C031938:calmidazolium; D000584:Amiloride; D002118:Calcium; C039614:ethylisopropylamiloride