Peracute Myocardial Infarction: Features of the Influence of α₂-Adrenoreceptor Stimulation on the Isolated Heart

We performed a comparative analysis of the effect of α₂-adrenoreceptor stimulation on the performance of Langendorff-isolated heart from rats with experimental myocardial infarction in the acute stage and sham-operated animals (control). In animals with peracute myocardial infarction, different agonist concentrations (clonidine, 10^-6 and 10^-9 M) produced a multidirectional effect on the left-ventricular developed pressure and speed and time parameters of heart contractility. In control rats, both concentrations of the agonist added to the perfused solution reduced contraction force. Clonidine in a concentration of 10^-6 M reduced HR in both groups and in a concentration of 10^-9 M, it decreased HR in control rats and caused multidirectional changes in rats with myocardial infarction. The coronary flow decreased in all series of experiments.