[The protective effect of EGb 761 in isolated isochemical/reperfused rat hearts]

This study was conducted to evaluate the effect of Ginkgo biloba extract (EGb 761) on the nitric oxide (NO) production in relation to the recovery of postischemic cardiac function in isolated working rat hearts. Rats were orally treated with various doses (25, 50, 75, and 100 mg/kg/day) of EGb 761 for 10 days. Hearts were isolated in "working mode" and subjected to 30 min ischemia followed by 120 min reperfusion. In the initial phase of reperfusion, NO production measured by electron spin resonance spectroscopy (ESR) was reduced by 85% in the 75 mg/kg/day of EGb 761 treated group in comparison with the drug-free ischemic/reperfused hearts. Inducible NO synthase (iNOS) messenger RNA (mRNA) measured by reverse transcription-polymerase chain reaction (RT-PCR) also was reduced by 41 and 58% in the groups treated with 75 and 100 mg/kg/day of EGb 761. Our findings show that EGb 761 directly acts as an NO scavenger and concomitantly inhibits the expression of iNOS mRNA. Thus, EGb 761 may act as a potent inhibitor of NO production under the condition of ischemia/reperfusion, improving the recovery of postischemic cardiac function.