Abstract
In the present investigation we measured various physiological parameters and blood levels of histamine and serotonin in anaphylaxis induced by the intravenous infusion of ascaris antigen.
Mongrel dogs, weighing 10-25kg, were anesthetized with intravenous administration of 2mg/kg of sodium pentobarbital. Catheters were inserted into the left femoral artery, bilateral femoral veins, left pulmonary truncus and left atrium. A probe of an electromagnet flow meter was placed around the ascending aorta. We measured tracheal pressure (PTR), pulmonary arterial pressure (PPA), femoral arterial pressure (PFA), left atrial pressure (PLA), and the cardiac output (QAORTA). Incrementally increasing doses of ascaris antigen were injected intravenously, and blood samples for the assay of histamine and serotonin were taken from the catheter inserted into the left femoral vein.
1) By the administration of ascaris antigen PPA, PLA, PFA and QAORTA showed a marked decrease and PTR showed an increase within a minute.
2) Plasma levels of histamine and serotonin showed a significant increase and reached the maximum value within a minute after the antigen challenge.
3) By repeated challenges with the ascaris antigen, late increase of PTR instead of anaphylactic shock was observed repeatedly within a short time.
The above results suggest that ascaris antigen challenge is a useful method to investigate the pathophysiology of anaphylaxis.
