ABSTRACT
<p><b>OBJECTIVE</b>To study the effects and mechanism of hydrogen peroxide (H2O2) of low concentration on dynamic changes of intracellular free calcium contents ([Ca2+]i) in cultural rat liver oval cells (WB-F344 cells).</p><p><b>METHODS</b>Using Fluo-3/Am as fluorescent indicator of [Ca2+]i and it was measured by laser scanning confocal microscope system.</p><p><b>RESULTS</b>The results showed that: (1) A rapid transient spiking of [Ca2+]i occurred after the stimulation of H2O2 of low concentration (800 nmol/L). (2) The [Ca2+]i increase was abolished by pretreated with catalase (CAT) or by incubated in D-Hank's solution containing EGTA, the chelate of extracellular Ca2+. (3) The [Ca2+]i increase was not inhibited by pretreated nifedipine, Ca2+ channel blocker, but was abolished by pretreated with anthracere-9-cardoxylic acid (A9C), the Cl-channel blocker and which also blocked calcium activated non-selective cation channel (CAN).</p><p><b>CONCLUSIONS</b>These results suggest that the increase of [Ca2+]i induced by H2O2 of low concentration may be due to the influx of extracellular Ca2+ through CAN.</p>