Reduction in inflammatory response by prior injection of a different agent at the same site: an experimental study in the rat.

Glycogen, producing a weak PMN response, and BHI/PP, which induces a strong response, have been injected both separately and sequentially into the peritoneal cavity of the rat. It was found that the first stimulus, glycogen, had a modifying effect on the response to the second stimulus, which was reduced. Changes in the number of PMNs in the peritoneal cavity were found to correspond to PMN count changes in the blood, which were monitored simultaneously. This suggests the possibility that the number of PMNs in an exudate is dependent on blood PMN numbers. The point at which the modifying mechanism has its effect remains to be demonstrated, and an assessment of the importance of the changes in blood counts is crucial in locating the point at which the two stimuli interact.