Tests of a Model for Macromolecular Migration on Myoblast Cell Surfaces Exposed to Alternating Electric Fields

摘要

The proposal that low frequency alternating electric fields may cause a net displacement of charged cell surface molecules similar to the effect observed with static electric fields is tested. Spherical myoblasts obtained from cultured embryos of Xenopus laevis were exposed for 30 min to static fields (2.5 to 9.5 V/cm) and for 30 to 75 min to 10- and 60-Hz electric fields in the range 18 toi 34 V/cm sub (p-p). Tests in electric fields were with normal medium (pH 7.8), a calcium and magnesium free (CMF) medium, or following pretreatment with neuramininidase in order to investigate dependence on cell surface molecular charge. Microflurimetry is used to measure the surface distribution of concanavilin A receptors as mapped by rhodamine tagged con A. Myoblasts exposed in AC fields in normal with and without neuraminidase pretreatment had essentially iotropic receptor distributions. However, a statistical analysis indicated a small anisotropy for exposures in 10- and 6-Hz fields at 60 min (p < .001), although there was no evidence of receptor redistribution to the extent observable with static fields. Fluorescence micrographs revealed no clustering or clumping of receptors. Cells exposed to 60 Hz fields in CMF medium had slightly more receptor anisotropy than those in normal medium, but, if real, effects were still small. The effects in CMF appear due to a sub-population of cells for which the aniosotropy was greater than under other exposure conditions, suggesting that altered divalent cation concentrations may enhance receptor motion in AC fields.