the effects of cimetidine on the respiratory burst of the rat’s neutrophils

background & objectives: neutrophils are the most important member of granulocytes & the first line of host defence against micro-organisms. they kill micro-organisms entering the body by phagocytic activity. one of the important phases of phagocytic activity is respiratory burst which can be effected by different drugs such as cimetidine. in this study the effects of cimetidine on respiratory burst of rat’s neutrophils are described. materials & methods: in this blind experimental case-control study 17 rats in two groups of case(8) & control (9) were selected. cimetidine & placebo were injected for one week & then the respiratory burst of neutrophils was evaluated with nitrobluetetrazolium test (nbt). the results were compared by using man-withney test (mw). results: it was showed that cimetidine had significant effects on neutrophil’s respiratory burst. mean of neutrophil’s respiratory burst was significantly more in case than control group(p<0.034). discussion: this study showed that cimetidine can stimulate respiratory burst in rat’s neutrophils. this may be due to effects of cimitidine on h2 histamine receptors on neutrophils. more studies are required to show effects of this drug on neutrophils’s. activities.