Asymmetrical bipolar nanosecond electric pulse widths modify bipolar cancellation

• Published in: Scientific reports 2017-11, Vol.7 (1), p.16372-12, Article 16372
• Main Authors: Valdez, Chris M., Barnes, Ronald A., Roth, Caleb C., Moen, Erick K., Throckmorton, Graham A., Ibey, Bennett L.
• Format: Article
• Language: English
• Subjects: 13/106; 14; 14/19; 14/34; 631/57; 631/57/2270; Calcium influx; Exposure; Humanities and Social Sciences; multidisciplinary; Physiology; Polarity; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-16142-6

A bipolar (BP) nanosecond electric pulse (nsEP) exposure generates reduced calcium influx compared to a unipolar (UP) nsEP. This attenuated physiological response from a BP nsEP exposure is termed “ bipolar cancellation ” ( BPC ). The predominant BP nsEP parameters that induce BPC consist of a positive polarity (↑) front pulse followed by the delivery of a negative polarity (↓) back pulse of equal voltage and width; thereby the duration is twice a UP nsEP exposure. We tested these BPC parameters, and discovered that a BP nsEP with symmetrical pulse widths is not required to generate BPC . For example, our data revealed the physiological response initiated by a ↑900 nsEP exposure can be cancelled by a second pulse that is a third of its duration.  However, we observed a complete loss of BPC from a ↑300 nsEP followed by a ↓900 nsEP exposure. Spatiotemporal analysis revealed these asymmetrical BP nsEP exposures generate distinct local YO-PRO®-1 uptake patterns across the plasma membrane. From these findings, we generated a conceptual model that suggests BPC is a phenomenon balanced by localized charging and discharging events across the membrane.