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.