The specific type IV phosphodiesterase inhibitor rolipram differentially regulates the proinflammatory mediators TNF-α and nitric oxide

Abstract We compared the effect of the specific type IV phosphodiesterase inhibitor rolipram on intracellular cAMP concentration, nitric oxide (NO) and tumour necrosis factor-α (TNF) formation in the murine macrophage cell line RAW 264.7. We found a dose-dependent increase of nitrite accumulation in LPS-stimulated macrophages from 17.5 to 25.1 μM nitrite with rolipram, whereas TNF synthesis was suppressed to less than 30% of control. This was accompanied by an increase from 7.4 to a maximum of 10.5 nM cAMP in RAW cells incubated with rolipram. These results were confirmed with the stable cAMP analogue ( S )- p -adenosine 3′,5′-cyclic phosphorothioate [( S )- p -cAMPS]. These findings demonstrate that elevation of cAMP in RAW 264.7 cells by rolipram decreases TNF synthesis and increases NO formation.