Changes of cell behavior by near-infrared signals.

3T3 mouse fibroblasts responded differently to specific near-infrared signals from epithelial CV1 cells. Furthermore, signals with the same wavelength and energy changed the percentages of attracted and repelled 3T3 cells if their intensity modulation was altered. I found this result in a 22 month long study which established a spectrum of motile responses of 781 individual 3T3 cells and 148 CV1 cells to the near-infrared emissions of microscopic, pulsating light sources using the infrared spot-irradiation phase-contrast (IRSIP) microscope [Albrecht-Buehler, 1991: J. Cell Biol. 114:493-502]. Thus the response of cultured, mammalian cells to near-infrared light signals is not merely a matter of total energy absorption by certain cytoplasmic components. Since it seems to depend on the cell type and the temporal pattern in which the light energy is emitted, it appears to imply the existence of a new kind of cellular information.