Spin traps in myocardial ischemia and reperfusion injury

Spin traps in myocardial ischemia and reperfusion injury 

Spin traps are diamagnetic organic molecules containing either nitroso (-N=0) or nitrone ( C=N— 0) functional groups. The spin-trapping reaction is a kinetic method in which the transient radical (R ) reacts with a nitrone or nitroso spin trap forming a more stable nitroxide spin adduct (Eqs. 1 and 2), which is readily detectable by ESR. 

Spin trap + Transient radical — Spin adduct. (2) 

The steady-state concentration of the spin adduct is dependent on the local concentration of spin trap, the number of transient radicals produced, the rate constant (k) for spin trapping and the decay of spin adducts. The rate constant (k) is primarily dependent on the nature of the transient radical and the structure of the spin trap. 

In recent years, spin traps have been used extensively to detect transient oxygen-derived radicals formed during myocardial ischemia and reperfusion [85-110]. However, except for few studies [110-115], the cardiovascular effects of spin traps have not been considered in detail. Since spin traps are reactive organic molecules, it is very plausible that they exert both pharmacologic and toxic effects on the myocardium. The objective of this study was to determine the effect of several structurally similar spin traps (either hydrophilic, lefthand side of Fig. 4) or hydrophobic, righthand side of Fig. 4) upon normal aerobic cardiac function and coronary flow rate in the isolated perfused rat heart. 

---