  We consider a neutralization of excited antiprotonic helium ion accompanied
by antiproton transitions to lower states in collisions with helium atoms
$(\bar{p}\mathrm{He}^{2+})_{nl} + \mathrm{He} \rightarrow \left[
(\bar{p}\mathrm{He}^{2+})_{n_f l_f} e\right]_{1s} + \mathrm{He}^+$ in
low-temperature medium. Interactions in the input and output channels are taken
similar to the potentials of $\mathrm{H}^+ - \mathrm{He}$ ($X^1\Sigma$) and
$\mathrm{H} - \mathrm{He}^+$ ($A^1\Sigma$) systems, respectively. The final
term is shifted down by the antiproton transition energy. Therefore initial and
final terms can intersect for the suitable antiproton quantum numbers leading
to an appreciable cross sections of the transitions. We have found that this
process can provide an additional increase of effective annihilation rates for
highly excited antiprotonic helium ion even in the low-density and temperature
target corresponding to known experimental conditions.
