  In the current paradigm of cosmic structure formation, dark matter plays a
key role on the formation and evolution of galaxies through its gravitational
influence. On microscopic scales, dark matter particles are expected to
annihilate amongst themselves into different products, with some fraction of
the energy being transferred to the baryonic component. It is the aim of the
present work to show that, in the innermost regions of dark matter halos,
heating by dark matter annihilation may be comparable to the cooling rate of
the gas. We use analytical models of the dark matter and gas distributions in
order to estimate the heating and cooling rates, as well as the energy
available from supernova explosions. Depending on the model parameters and the
precise nature of dark matter particles, the injected energy may be enough to
balance radiative cooling in the cores of galaxy clusters. On galactic scales,
it would inhibit star formation more efficiently than supernova feedback. Our
results suggest that dark matter annihilation prevents gas cooling and star
formation within at least $0.01-1$ per cent of the virial radius.
