The role of rat
anaphylatoxin in histamine release and increased vascular permeability during the first thirty minute period in
zymosan-air-pouch
inflammation, an experimental model of
inflammation induced by
zymosan in an air-pouch prepared on the back of rats, was investigated.
Complement depletion by
cobra venom factor did not affect the histamine release nor the increased vascular permeability in the
inflammation of this type. In spite of apparent
anaphylatoxin activity,
zymosan activated serum (ZAS) failed to cause any significant release of
histamine when infused in the air-pouch on the back.
Anaphylatoxin purified from rat serum activated with
zymosan in the presence of an inhibitor (
epsilon-aminocaproic acid) of
anaphylatoxin inactivator gave a single band in both
polyacrylamide gel electrophoresis (PAGE) and SDS-PAGE. The molecular weight estimated by SDS-PAGE was approx. 7,000. The purified rat
anaphylatoxin failed to induce histamine release nor increased vascular permeability even at 50 micrograms/ml, although it caused contraction of guinea pig ileum at 0.8 micrograms/ml. These results suggest that rat
anaphylatoxin does not participate in histamine release and increased vascular permeability in the
zymosan-air-pouch
inflammation.