Rolipram is a phosphodiesterase-4 (PDE 4) inhibitor. It is being researched as a possible alternative to current antidepressants (Washtel, 1983; Bobon et al., 1988). Recent studies show that rolipram may have antipsychotic effects (Maxwell et al.,2004; Kanes et al., 2006).There is a conflicting data about the role of nitric oxide (NO) in arthritic diseases. In the present work, we examined whether the suppression of NO production by L- NG - monomethyl arginine (L-NMMA), a non-selective NOS inhibitor or addition of exogenous NO by administration of sodium nitroprusside (SNP) can modify the...