Histamine contents in hearts and whole blood during early myocardial ischemia in 3 rodents

Release of cardiac histamine (H) by coronary artery ligation (CAL) in anesthetized dogs initiated early ischemic arrhythmias. Our purpose was to determine whether the H contents (by fluorospectrophotometric determination) in heart and whole blood were altered by CAL in anesthetized rats, guinea pigs and rabbits. The myocardial H contents in ischemic zone of left ventricle were decreased in these rodents 20 min after CAL. While the H concentration in the whole blood increased in rats. but not in other 2 species. The cardiac H contents were decreased by 42, 25 and 23% in rats. guinea pigs and rabbits, respectively. Thus, cardiac H changes induced by myocardial ischemia were different among rodents and rats seemed to be more sensitive than rabbits and guinea pigs.