Inosine is a positive inotropic agent and dilates coronary blood vessels. During
ischemia,
inosine infusion increases blood flow, resulting in decreased myocardial damage. We wished (a) to determine
inosine's effect in isolated rat hearts and (b) to determine if
inosine attenuates myocardial dysfunction after transient global
ischemia. Developed left ventricular pressure (LVP), LV dP/dt, and coronary perfusion pressure were monitored in hearts receiving
Krebs-Henseleit buffer (KHB) (n = 10) or KHB + 2 mM
inosine (n = 4). KHB + 2 mM
inosine significantly reduced coronary perfusion pressure by 21% but had no effect on developed LVP or LV dP/dt. Hearts receiving KHB (n = 6) or KHB + 2 mM
inosine (n = 5) were subjected to 15-min global
ischemia followed by 30-min reperfusion with KHB. Recovery of LVP, LV dP/dt, the incidence of arrhythmias, and the time to peak recovery of developed LVP was not different between groups. In two additional hearts, KHB + 2 mM
inosine administered during reperfusion had no effect on developed LVP, LV dP/dt, or coronary perfusion pressure. Thus, unlike other preparations,
inosine pretreatment did not significantly affect the time course of postischemic functional recovery of rat myocardium.