Nanosecond electric pulse-induced calcium entry into chromaffin cells.
Electrically excitable bovine adrenal chromaffin cells were exposed to nanosecond duration electric pulses at field intensities ranging from 2 MV/m to 8 MV/m and intracellular calcium levels ([Ca(2+)](i)) monitored in real time by fluorescence imaging of cells loaded with Calcium Green. A single 4 ns, 8 MV/m pulse produced a rapid, short-lived increase in [Ca(2+)](i), with the magnitude of the calcium response depending on the intensity of the electric field. Multiple pulses failed to produce a greater calcium response than a single pulse, and a short refractory period was required between pulses before another maximal increase in [Ca(2+)](i) could be triggered. The pulse-induced rise in [Ca(2+)](i) was not affected by depleting intracellular calcium stores with caffeine or thapsigargin but was completely prevented by the presence of EGTA, Co(2+), or the L-type calcium channel blocker nitrendipine in the extracellular medium. Thus, a single nanosecond pulse is sufficient to elicit a rise in [Ca(2+)](i) that involves entry of calcium via L-type calcium channels.
Vernier
P Thomas
PT
MOSIS, Information Sciences Institute, Viterbi School of Engineering, University of Southern California, Marina del Rey, CA, USA.
Sun
Yinghua
Y
Chen
Meng-Tse
MT
Gundersen
Martin A
MA
Craviso
Gale L
GL
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D019439:Chromaffin Cells / Q000187:drug effects / Q000378:metabolism*; D004563:Electrochemistry; D004583:Electrons; D018274:Electroporation; D013997:Time Factors
D015220:Calcium Channels; D002614:Chelating Agents; D002118:Calcium