PF-04822163 is an orally active, selective, and blood-brain barrier permeable PDE1 inhibitor with IC 50 values of 2 nM, 2.4 nM, and 7 nM for PDE1A , PDE1B , and PDE1C respectively. PF-04822163 can be used in the research of attention deficit hyperactivity disorder or Parkinson's disease.