Cellular exposure to nanosecond pulsed electric fields (nsPEF) are believed to cause immediate creation of
nanopores in the plasma membrane. These nanopores enable passage of small ions, but remain impermeable to
larger molecules like propidium iodide. Previous work has shown that nanopores are stable for minutes after
exposure, suggesting that formation of nanopores in excitable cells could lead to prolonged action potential
inhibition. Previously, we measured the formation of nanopores in neuroblastoma cells by measuring the influx of
extracellular calcium by preloading cells with Calcium Green-AM. In this work, we explored the impact of changing
the width of a single nsPEF, at constant amplitude, on uptake of extracellular calcium ions by primary hippocampal
neurons (PHN). Calcium Green was again used to measure the influx of extracellular calcium and FM1-43 was used
to monitor changes in membrane conformation. The observed thresholds for nanopore formation in PHN by nsPEF
were comparable to those measured in neuroblastoma. This work is the first study of nsPEF effects on PHN and
strongly suggests that neurological inhibition by nanosecond electrical pulses is highly likely at doses well below
irreversible damage.
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