Abstract: The objective of this paper war to study the activity change of cyclic adenosine monophosphatephosphodiesterase (cAMP-PDE) in neutrophils of dogs with canine distemper and its regulation by Chinese herbs in vitro and to provide data for further studies of antiinflammatory agents and Chinese herbal therapies on viral inflammation. cAMP-PDE was obtained from neutrophils which isolated from dogs having distemper (n=9) (distemper group) and normal dogs (n=6) (control group), and the influences of Chinese herbs on activity of the cAMP-PDE was detected by high performance liquid chromatography (HPLC). The results showed that the activity of cAMP-PDE extracted from neutrophils of distemper group (18.55%±2.66%) was significantly higher than that of the control group (11.54%±5.16%) (P<0.05). 14 traditional Chinese medicines out of 5 types 114 medicines (drugs for relieving exterior syndrome etc.) were significantly inhibit the activity of cAMP-PDE ,including rhizoma phragmitis(77.27%), figwortflower picrorhiza rhizome (70.41%), glossy privet fruit (65.50%), haichow elsholtzia herb (65.16%), fritillariae tuber (61.43%), scutellaria (60.67%), sagittate epimedium (60.34%), astragalus mongholicus (59.13%), herba artemisiae annuae (56.93%) cortex fraxini (55.55%), biond magnolia flower (55.03%), glycyrrhiza uralensis (54.67%), fructus Arctii (53.40%) and ephedra herb (53.32%)，respectively.Those results indicate that the activity of cAMP-PDE in neutrophils plays an important role in the progress of inflammation of dogs with canine distemper.The Chinese herbs might have therapeutic effect on canine distemper because of its comparatively strong inhibitory effects on cAMP-PDE,and inhibiting the activity of cAMP-PDE in neutrophils might be one of the mechanism of Chinese herbs antiinflammatory. 

Key words: canine distemper; polymorphonuclear; neutrophil; phosphodiesterase; Chinese herbs