  Bars in disc-dominated galaxies are able to drive gas inflow inside the
corotation radius, thus enhancing the central star formation rate (SFR).
Previous work, however, has found that disc-dominated galaxies with centrally
suppressed SFR frequently host a bar. Here we investigate possible causes for
the suppression of central SFR in such cases. We compare physical properties of
a sample of disc-dominated barred galaxies with high central SFR (HC galaxies)
with those of a sample of disc-dominated barred galaxies with low central SFR
(LC galaxies). We find that the two samples have on average similar HI content
and bars of similar strength. But we also find that the HCs have bluer colors
than LCs, and that outside the bar region they host stronger spiral arms than
the LCs where closed rings are more often seen. We discuss and evaluate the
possible causes for the suppression of the central SFR in the LC galaxies as
opposed to its enhancement in the HC galaxies.
