  The only comparative study of the inclusive pion single-spin asymmetries
produced in the interactions of the polarized protons and antiprotons in
collisions with unpolarized proton was carried out at E-704 experiment.
Significant asymmetries were found at large $x_{F}$ and middle $p_{T}$,
$\pi^{+}$ and $\pi^{0}$ asymmetries have positive signs while $\pi^{-}$ has
negative one in the $p^{\uparrow}+p$ collisions, while in the
$\bar{p}^{\uparrow}+p$ interactions the $\pi^{-}$ and $\pi^{0}$ asymmetries
have positive signs while $\pi^{+}$ has negative sign. Similar experimental
study can be done in the SPASCHARM experiment at U-70 accelerator at IHEP for
various secondary particles with the use of 16 GeV polarized proton and
antiproton beams.
