Effects of Ginkgo Biloba on changes induced by quantitative cerebral microembolization in rats

Unilateral embolization of the brain was performed in rats by the intracarotid injection of 4000 radioactive microspheres (50 micron). The local blood flow was determined using the iodoantipyrine technique in the hippocampus, hypothalamus, striatum and remainder of the brain. Embolization resulted in a decrease in the blood flow and a modification of the distribution of microflow. Besides, the embolization produced changes in energy metabolism, specially a fall in ATP and glucose levels and an increase in lactate level. Subsequently severe vasogenic cerebral edema developed. There was a correlation between the number of microspheres injected and the extent of edema. Pretreatment with an extract of Ginkgo Biloba leaves partially suppressed the effects of the embolization. An increase in the blood flow associated with normalization of cellular energy metabolism explained the decrease in brain edema.