  The high density effects should be manifest at small x and/or large nuclei.
In this letter we consider the behavior of nuclear structure function $F_2^A$
slope in the kinematic region which could be explored in the future eA
colliders as a search of these effects. We verify that the high density implies
that the maximum value of the slope occurs at large values of the photon
virtuality, i.e. in a perturbative regime, and is dependent of the number of
nucleons A and energy. Our conclusion is that the measurement of this
observable will allow to explicit the saturation.
