Effect of If Current Blockade on Newborn Rat Heart Isolated According to Langendorff

The study examined the effects of hyperpolarization-activated funny current (If) on HR and coronary flow in Langendorff-isolated hearts from newborn rats. Blockade of If current with ZD7288 changed the examined cardiac parameters. The blocker in a concentration of 10 —9 M decreased HR by 26.8% ( p ≤0.05). In concentrations 10 —8 , 10 —7 , 10 —6 , and 10 —5 M ZD7288 produced minor differently directed effects. In a concentration of 10 —5 M, ZD7288 reduced coronary flow in the isolated heart ( p ≤0.01). In other concentrations, the blocker produced no significant effects on coronary flow.