Abstract
Anaphylactic, trypsin, and peptone shock are closely related phenomena. The prominent symptoms are similar and the intravenous injection of antigen, trypsin, or proteose into intact animals has been shown to result in the liberation of significant amounts of histamine. 1-3 It has also been shown that the addition of antigen, trypsin, or proteose to rabbits' blood (rendered incoagulable with heparin) leads to the release of histamine from cells to plasma. 4-9 It is possible that the mechanisms of the release are the same in each case. A study of the effect of various agents in inhibiting or augmenting the release of histamine by the above substances suggests itself as a means of determining whether similar mechanisms are involved. Inasmuch as rabbits' blood can be divided into samples which can be considered identical in every respect, this tissue seems to provide an ideal medium for such studies.
It has been shown that heparin is capable of inhibiting the proteolysis of various substrates by trypsin, 10 , 11 and we have found that heparin antagonizes the toxic effects of trypsin in intact animals. 12 Consequently the present experiments were performed to determine whether heparin has an inhibitory effect upon the release of histamine by trypsin, and if so, to examine the effect of heparin upon the release of histamine by antigen and by proteose.
Experimental. Blood was obtained from unanesthetized rabbits by cardiac puncture. Sufficient heparin† was added to this blood to prevent clotting, a concentration of 0.02%. Each blood sample was divided into 3 tubes. Saline was added to the first tube; specific antigen, trypsin, or proteose was added to the second tube; and specific antigen, trypsin. Or proteose plus additional heparin, a final concentratin of 0.12% was added to the third tube.
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