CELL-MEMBRANE LIPID MOLECULAR-DYNAMICS IN A SOLENOID VERSUS A MAGNETICALLY SHIELDED ROOM

The generalized polarization function of the fluorescent probe 2-dimet hylamino-6-lauroylnaphthalene has been used to evaluate the lipid dyna mics in Friend erythroleukemia cell membrane. The values of this funct ion varied during the culture growth cycle, showing decreased lipid dy namics 24-48 h from the cell seeding. When the cycle occurred in a sol enoid producing a magnetic field of 70 mu T at 50 Hz in addition to th e 45 mu T DC of the earth (short-term 4-day exposure), the membrane li pid dynamics during this same time-period decreased by about 10% (P < .04). After long-term (184 days) or extremely long-term (395 days) exp osure of the cells to the magnetic field, little additional variation in the membrane lipid dynamics was observed, suggesting an adaptation phenomenon. A variation of membrane lipid dynamics was also observed d ue to in vitro cell differentiation (P < .02). Nevertheless, the expos ure of both undifferentiating and differentiating cells to a highly at tenuated magnetic field in a magnetically shielded room (20 nT DC plus 2.5 pT AC) did not induce any modification of membrane lipid dynamics . (C) 1998 Wiley-Liss, Inc.