Dopamine has been widely used in the past for improving renal function but was abandoned due to lack of evidence and various potential serious side effects. In the new Heart Failure Guidelines 2013 of the AHA.pdf there is an interesting note in the section hospitalized patients with heart failure: low-dose dopamine infusion may be considered in addition to loop diuretic therapy to improve diuresis and better improve renal function.
The level of evidence is IIb/B which means that efficacy is less well established and that there is greater conflicting evidence from trials. Indeed, when looking at the cited articles more questions than answer remain... but see yourself.
Giamouzis G, et al. .J Card Fail. 2010 Dec;16(12):922-30
Elkayam U, et al. Circulation. 2008 Jan 15;117(2):200-205