CGS 21680, dibutyryl cyclic AMP and rolipram attenuate the pro-inflammatory interactions of the Pseudomonas aeruginosa -derived pigment, 1-hydroxyphenazine, with human neutrophils

Reduction of infarct size and postischemic inflammation from ATL-146e, a highly selective adenosine A2A receptor agonist, in reperfused canine myocardium

Adenosine and adenosine A(2A) receptor agonists have been shown to limit myocardial infarct size when given at vasodilatory doses during reperfusion. This beneficial effect is thought to be due, in part, to stimulation of adenosine A(2A) receptors on inflammatory cells. The specific aims of this study were to determine whether the anti-inflammatory and cardioprotective properties of a novel adenosine A(2A) receptor agonist, ATL-146e (ATL), alone or in combination with the phosphodiesterase IV inhibitor rolipram would occur using very low, nonvasodilating doses. In a canine model of reperfused myocardial infarction, low-dose ATL given alone reduced infarct size by 45% (P < 0.05 vs. control). When ATL was combined with a very low dose of rolipram (0.001 microg.kg(-1).min(-1)), a marked reduction in P-selectin expression and neutrophil infiltration (51% lower; P < 0.001 vs. control) was seen and the infarct size reduction (58% lower; P < 0.01 vs. control) was greater than observed with ATL (45% lower; P < 0.05) or rolipram (33% lower; P < 0.05) alone. In conclusion, a low, nonvasodilating dose of ATL, a highly selective adenosine A(2A) receptor agonist, reduced infarct size after reperfusion. Furthermore, combining ATL and the phosphodiesterase IV inhibitor rolipram reduced infarct size even more than either agent alone. Such combination therapy may be beneficial clinically by potentiating cardioprotection after coronary reperfusion at doses far below those producing vasodilatation or side effects.

The antidepressant and antiinflammatory effects of rolipram in the central nervous system

Rolipram is a selective inhibitor of phosphodiesterases (PDE) IV, especially of the subtype PDE IVB. These phosphodiesterases are responsible for hydrolysis of the cyclic nucleotides cAMP and cGMP, particularly in nerve and immune cells. Consequences of rolipram-induced elevation of intracellular cAMP are increased synthesis and release of norepinephrine, which enhance central noradrenergic transmission, and suppress expression of proinflammatory cytokines and other mediators of inflammation. In humans and animals rolipram produces thereby a variety of biological effects. These effects include attenuation of endogenous depression and inflammation in the central nervous system (CNS), both effects are of potential clinical relevance. There are some discrepancies between in vitro and in vivo effects of rolipram, as well as between results obtained in animal models and clinical studies. The clinical use of rolipram is limited because of its behavioral and other side effects. Newly developed selective PDE IV inhibitors with presumably higher potency and lower toxicity are currently under investigation.