Effect of Hyperpolarization-Activated Current Blockade on the Isolated Rat Heart during Long-Term Consequences of Experimental Myocardial Infarction
摘要
Hyperpolarization-activated currents blockade (If) (ZD7288, 10–9 M) had a multidirectional effect on the left ventricular developed pressure in sham-operated (SO) rats and decreased this parameter in rats with long-term consequences of myocardial infarction (lcMI). The If blocker (10–5 M) increased the left ventricular developed pressure in SO rats and decreased it in the lcMI group. Heart rate of the isolated heart after If blockade decreased in both experimental groups. If blockade (10–9 M) produced multidirectional changes in coronary flow (CF) in the lcMI group and decreased CF in the SO group. The maximum concentration of the blocker reduced CF in both experimental groups. The duration of contraction of the isolated heart decreased after addition of If blocker at a minimum concentration, while the maximum concentration of If blocker increased this parameter in both groups. The If blocker increased the duration of relaxation of the isolated heart at both concentrations in all groups, the greatest changes were observed in the SO group. The duration of the contraction cycle during If blockade (10–9 M) increased in the SO group and did not change significantly in the lcMI group. At a concentration of 10–9 M, the blocker increased the duration of the contraction cycle in both groups.