  Galaxy nuclei are a unique laboratory to study gas flows. High-resolution
imaging of the gas flows in galactic nuclei are instrumental in the study of
the fueling and the feedback of star formation and nuclear activity in nearby
galaxies. Several fueling mechanisms can be now confronted in detail with
observations done with state-of-the-art interferometers. Furthermore, the study
of gas flows in galactic nuclei can probe the feedback of activity on the
interstellar medium of galaxies. Feedback action from star formation and AGN
activity is invoked to prevent galaxies from becoming overly massive, but also
to explain scaling laws like black hole (BH)-bulge mass correlations and the
bimodal color distribution of galaxies. This close relationship between
galaxies and their central supermassive BH can be described as co-evolution.
There is mounting observational evidence for the existence of gas outflows in
different populations of starbursts and active galaxies, a manifestation of the
feedback of activity. We summarize the main results recently obtained from the
observation of galactic inflows and outflows in a variety of active galaxies
with current millimeter interferometers like ALMA or the IRAM array.
