LOCAL CHANGES IN MEMBRANE-POTENTIAL INTENSIFY NEUTROPHIL OXIDATIVE BURST

The aim of this paper is to study the effects of the pulsed electrical field/current alone or combined with ionomycin, fMLP and PMA, the che mical stimuli that operate through distinctly different activation pat hways, on the time course of the oxidative burst response in human neu trophils. Neither the control groups nor the neutrophils treated with electrical field alone shelved any increase in oxidative burst activit y measured by the luminol-enhanced chemiluminescence technique, It was found that electrical treatment potentiates chemically induced activa tion with either of the chemical stimulators used. The integrated oxid ative burst response-which represents a cumulative amount of oxygen me tabolites produced during whole response-was 87% higher in neutrophils treated with a combination of ionomycin and an electric field than in solely ionomycin treated cells, while the peak level of the response was 114% higher. In neutrophils stimulated with fMLP the electrochemic al treatment caused a 32% higher integral response as well as a 22% hi gher peak level compared to the neutrophils treated with chemical stim ulant alone, The integrated oxidative burst response in the combined P MA and electric treatment was only 4.7% higher than in the cells treat ed with PMA alone, and no significant difference in the peak level was found, The results suggest that electric field treatment preferential ly stimulates calcium-induced activation with ionomycin rather than ca lcium-dependent activation with fMLP or PMA.