Nanosecond pulse electric field (nanopulse): A novel non-ligand agonist for platelet activation

Abstract

Nanosecond pulse stimulation of a variety of cells produces a wide range of physiological responses (e.g., apoptosis, stimulation of calcium (Ca 2+) fluxes, changes in membrane potential). In this study, we investigated the effect of nanosecond pulses, which generate intense electric fields (nsPEFs), on human platelet aggregation, intracellular free Ca 2+ ion concentration ([Ca 2+] i) and platelet-derived growth factor release. When platelet rich plasma was pulsed with one 300 ns pulse with an electric field of 30 kV/cm, platelets aggregated and a platelet gel was produced. Platelet aggregation was observed with pulses as low as 7 kV/cm with maximum effects seen with approximately 30 kV/cm. The increases in intracellular Ca 2+ release and Ca 2+ influx were dose dependent on the electrical energy density and were maximally stimulated with approximately 30 kV/cm. The increases in [Ca 2+] i induced by nsPEF were similar to those seen with thapsigargin but not thrombin. We postulate that nsPEF caused Ca 2+ to leak out of intracellular Ca 2+ stores by a process involving the formation of nanopores in organelle membranes and also caused Ca 2+ influx through plasma membrane nanopores. We conclude that nsPEFs dose-dependently cause platelets to rapidly aggregate, like other platelet agonists, and this is most likely initiated by the nsPEFs increasing [Ca 2+] i, however by a different mechanism.