EFFECTS OF LOW-FREQUENCY ELECTRIC FIELDS ON THE INTRACELLULAR Ca²⁺ RESPONSE INDUCED IN HUMAN VASCULAR ENDOTHELIAL CELLS BY VASOACTIVE SUBSTANCES

Abstract

Human vascular endothelial cells (HUVEC) were exposed to air electric fields of 30 kV/m, 50 Hz for 24 hr. After exposure, the change in intracellular Ca²⁺ concentration ([Ca²⁺]_i) induced by the vasoactive substances ATP and histamine were determined using confocal laser scanning microscopy. A statistically significant increase in [Ca²⁺]_i was observed following stimulation with 100 μM ATP, compared with the results in sham-exposed cells (22%, p<0.05, n=20). No changes in [Ca²⁺]_i due to the field were observed after stimulation with histamine, showing that the effect of the field on the change in [Ca²⁺]_i was agonist-specific. The Ca²⁺ concentration in the medium was low, suggesting that the ATP-induced increase in [Ca²⁺]_i in cells exposed to electric fields was due to the release of Ca²⁺ from intracellular stores. The results suggested that the applied low-frequency electric field affected the function of HUVEC via a change in [Ca²⁺]_i.

• Low-frequency electric fields
• Intracellular Ca²⁺ response
• Human vascular endothelial cells