Effect of Endotoxin and Anaphylatoxin on Rat Mast Cells and Chopped Rat Lung 1

Conclusions

1. Neither endotoxin, nor anaphylatoxin generated by the action of endotoxin on rat serum, released histamine from rat mast cell suspensions. 2. Preformed anaphylatoxin, but not endotoxin alone, released histamine from chopped rat lung. 3. We confirmed reports that endotoxin (and agar) causes generation of an anaphylatoxin in rat serum. 4. Although anaphylatoxin generated by either endotoxin or agar does not release histamine from rat serous fluid mast cells, it does release histamine from rat chopped lung, suggesting that formation of an anaphylatoxin may be one mechanism for release of histamine by endotoxin in vivo.