The Effects of Ginseng Saponin on Relaxation of Smooth Muscle in the Lower Urinary Tract and the Corpus Cavernosum

Jung, Hee Chang; Oh, Tae Hee

Abstract

BACKGROUND: Korean ginseng (KG) has been used as a general tonic, and for voiding dysfunction for a long time in oriental society. However, scientific basic studies on the use of KG, have been rare, especially for voiding and erectile dysfunction. This study was performed to investigate the effects of KG on voiding and erectile function by examining the effects of total saponin (TS) on the bladder, urethral and penile cavernosal smooth muscle. MATERILAS AND METHODS: To examine the effects of TS, NewZeland white rabbits were used to obtain tissue strips from the smooth muscle of the bladder, proximal urethra and corpus cavernosum. Adult Sprague Dawley rats were used to examine the changes in urodynamic findings and penile erection after administration of TS.
RESULTS
In proximal urethral strips, the rate of relaxation of the proximal urethra was increased from 9.0+/-2.9 to 33.7+/-4.8% in a dose-dependent manner when the concentration of TS was added accumulatively from 0.25 mg/ml to 4.0 mg/ml (p<0.05). However, no significant response was observed in the bladder strips within these concentration ranges. For the corpus cavernosal strips, the rate of relaxation ranged from 5.8+/-2.1 to 36.7+/-5.8%, increasing in a dose-dependent manner when TS was increased from 1.0 mg/ml to 4.0 mg/ml (p<0.05). After administration of 0.1 ml of TS (32 mg/ml) in the rat, the bladder pressure was 37.5+/-8.5 mmHg at 52.1+/-7.0 sec. during isovolumetric bladder contraction, showing no significant differences from 35.7+/-7.8 mmHg and 50.7+/-7.2 sec, respectively, before treatment. However, when 0.1 ml of TS (32 mg/ml) was administered, the relative reduction of urethral pressure was 6.9+/-0.5 mmHg at 62+/-7.5 sec, which was significantly higher compared to 4.6+/-1.1 mmHg at 45+/-10 sec before treatment (p<0.05). For the cavernosal injection study, the change in intracavernosal pressure (delta ICP) was examined after administering 0.1 ml of TS. The cumulative additions of TS at concentrations from 0.5 mg/ml to 32 mg/ml increased delta ICP from 1.3+/-0.5 to 21.3+/-7.8 mmHg in a dose-dependent manner (p<0.05). The duration of tumescence was from 0.3+/-0.1 to 5.2+/-0.2 min, showing dose-dependent increase (p<0.05). Furthermore, the cumulative addition of TS at concentrations from 0.5 mg/ml upto 32 mg/ml did not cause any significant change in systemic blood pressure.
CONCLUSION
These results suggest that ginseng improves voiding functions, which is mainly achieved by TS relaxing the proximal urethra, the most important part of the bladder outlet function. In addition, ginseng safely induced a penile erection hemodynamically by relaxing the corpus cavernosum.