Thimerosal causes calcium oscillations and sensitizes calcium-induced calcium release in unfertilized hamster eggs.
Calcium-induced-calcium-release (CICR) was assayed in unfertilized golden hamster eggs by injecting Ca2+ and monitoring Ca2(+)-dependent hyperpolarizing responses (HRs) and Ca2(+)-sensitive fluo-3 fluorescence. Incubating eggs in the sulfhydryl reagent thimerosal caused [Ca2+]i oscillations as monitored by Ca2(+)-dependent HRs and decreased approximately 10-fold the Ca2+ injection current required to generate an HR and cause a large intracellular Ca2+ increase. Thimerosal also enhanced the sensitivity of eggs to Ca2+ injection in a calcium-free medium. The effects of thimerosal on CICR were prevented by dithiothreitol and were not mimicked by injecting inositol 1,4,5-trisphosphate. The data suggest that thimerosal may be an alternative agent for studying CICR in caffeine-insensitive cells.
Swann
K
K
MRC Experimental Embryology, St. George's Hospital Medical School, London, UK.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006224:Cricetinae; D003593:Cytoplasm / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D008647:Mesocricetus; D010063:Ovum / Q000378:metabolism*; D010507:Periodicity; D013849:Thimerosal / Q000494:pharmacology*
D013849:Thimerosal; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium