S-(+)-Rolipram

S- (+)-Rolipram is a less active enantiomer of the PDE4 inhibitor with an EC50 of 1.0 uM. It is an anti-inflammatory drug. Rolipram is being studied as a possible alternative to current antidepressants. Recent studies show that rolipram may have antipsychotic effects. It displays activity 10-fold less than R-rolipram at inhibition of PDE IV. It inhibits antigen-induced contraction of guinea-pig colonic smooth muscle.