  The gravity effects in high-energy scattering, described by a
four-dimensional eikonal amplitude related to gravireggeons induced by compact
extra dimensions are studied. It is demonstrated that the real part of the
eikonal (with a massless mode subtracted) dominates its imaginary part at both
small and large impact parameters, in contrast to the usual case of hadronic
high-energy behavior. The real part of the scattering amplitude exhibits an
exponential falloff at large momentum transfer, similar to that of the
imaginary part of the amplitude.
