Effects of MR exposure on axonal outgrowth in the sympathetic nervous system of the chick.

The effects of MR exposure on the rate and specificity of sympathetic preganglionic axonal outgrowth were examined in the chick embryo. Embryos were exposed to a static magnetic field of 1.5 T for 6 hours, 64 MHz RF field pulses, and a switched magnetic field gradient of amplitude 0.6 G/cm for 4 hours. No significant difference in axonal outgrowth was observed between MR-exposed and control embryos. In addition, the distributions of several major extracellular matrix (ECM) molecules, laminin, fibronectin, and collagen IV, were examined. Immunostaining patterns of these ECM molecules during axonal outgrowth showed no difference between MR-exposed and control embryos. Our results suggest that the MR exposure conditions used in this study do not affect axonal outgrowth in the sympathetic nervous system of the chick.