Effect of Ginseng-20S-prosapogenin on Tissue Blood Flow Measured by the Hydrogen Clearance Method in Sympathicotonic- or Parasympathicotonic-type Stressed Mice

An attempt was made to investigate the preventive effects of 20S-prosapogenin (20S-PG), a partial hydrolyzate of diol saponins isolated from Panax ginseng, on changes of peripheral tissue blood flow in diseased model animals with vagotonic-type autonomic imbalance [SART (specific alternation of rhythm in temperature)-stressed (repeated cold-stressed) mice developed by us], and sympathicotonic-type stressed mice [restraint and water immersion-stressed (R WIS) mice], using the hydrogen clearance method. Decreases in gastric blood flow in both body and pyloric regions of the stomach and increases in dermal blood in both the shoulder and lumbar region in SART-stressed mice were prevented to a considerable extent by daily treatments with 20S-PG, 2.5-10 mg/kg/d. Similarly, the marked decrease in gastric blood flow following R WIS loading was significantly blocked by 10 mg/kg/d of 20S-PG. 20S-PG had a minor preventive effect on decreases in hepatic and dermal blood flow in R WIS mice. The preventive effect of 20S-PG on changes in tissue blood flow, recognized in model animals with autonomic imbalance not only in the vagotonic state but also in the sympathicotonic state, is therefore regarded with considerable interest and may provide a clue to explain the pharmacological action of ginseng.