In vivo production of nitric oxide in the canine heart in IgE-mediated anaphylaxis

We investigated the production of nitric oxide (NO) in the canine anaphylactic heart in vivo using an NO-selective electrode. Seven dogs with positive sensitivity to Ascaris Suum were studied, Ascaris Suum was administered into the systemic circulation to induce anaphylaxis, and NO, blood pressure, heart rate, end-diastolic left ventricular pressure, cardiac output, and the maximum rate of rise of left ventricular pressure were monitored for 60 min. The electrode was placed on the surface of the left ventricle adjacent to the interventricular branches of the left coronary artery, NO concentration increased significantly during the period from 2 to 3 min, and tended to increase during the period from 4 to 15 min after antigen challenge, and almost returned to baseline after 20 min, In conclusion, increases in NO in the heart are only observed during the early phase of anaphylaxis.