Acute myocardial infarction enhances the portal venous histamine level in dogs

Objective and Design: The aim of our experiments was to determine the plasma histamine level in the portal venous (VP) blood during acute coronary occlusion and reperfusion. Subjects: 27 adult mongrel dogs of either sex were randomized for three groups: sham-operated controls, occlusion group (group O) and reperfusion group (group R). Treatment: The left circumflex coronary artery (LCx) was proximally occluded and the occlusion was maintained during 6 h (group O), or after a 60-min occlusion the LCx was reperfused (group R). The portal vein was cannulated to take blood samples for hormone measurements. Methods: The plasma histamine concentrations were measured with the radioenzymatic method. Results: The VP plasma histamine level was significantly increased 60 min after the LCx occlusion in groups O (99.9 +/- 40.2 vs. 252.9 +/- 100 pg/ml, mean +/- SD) and R (101.2 +/- 55.1 vs. 179.8 +/- 96 pg/ml), and remained high in group O (240.4 +/- 81 pg/ml), while 2 h after LCx reperfusion it had decreased to the basic level. There was no correlation between the hemodynamic parameters and the portal Vein plasma histamine levels. Conclusions: Histamine is released into the gastrointestinal tract during acute myocardial ischemia and reperfusion, but the release of the vasoactive drug has no effect on systemic hemodynamics.