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Effects of American Ginseng on Erectile Function and Sexual Behaviour. Matthew Barnes Supervisor: Lique Coolen The University of Western Ontario. Introduction: Erectile dysfunction. There is a growing demand for phosphodiesterase 5 (PDE5) inhibiters ( Wessells et al 2001)
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Effects of American Ginseng on Erectile Function and Sexual Behaviour Matthew Barnes Supervisor: Lique Coolen The University of Western Ontario
Introduction: Erectile dysfunction There is a growing demand for phosphodiesterase 5 (PDE5) inhibiters (Wessells et al 2001) Furthermore, men with type 2 diabetes have a 28% prevalence of erectile dysfunction (Feldman et al 1994) HOWEVER, 46% of men with type 2 diabetes don’t respond to PDE5 inhibitors (Rendell et al 1999) Finally, after a year of treatment, men with type 2 diabetes who respond positively to treatment may revert back to pretreatment conditions(Penson et al 2003)
Ginseng improves erectile function • Ginseng (North American and Korean Red) • Facilitates sexual behavior in rats (Murphy et al 1998) • Korean Red Ginseng: • Causes vasodilation in erectile tissue: corpus cavernosum (rabbit, canine)(Kang et al 2005, Chen and Lee 1995)
Ginseng and Diabetes • Decreased eNOS mRNA and expression (Xie et al 2007) • Increase eNOS phosphorylation Yu et all 2007) • Decreased VEGF expression and mRNA (Musicki et al 2004) • Increase VEGF expression via glucocorticoid receptor activation (Leung et al 2006) • Hyperglycemia → ROS → lipid peroxidation and upregulated cytokines and adhesion molecules → vascular damage (Yan et al 2008) • Antioxidant (Cho et al 2006) • Increase glutathione and decrease markers for lipid peroxidation (Ryu et al 2005) • Decreasing glucose levels in blood (Ji and Gong 2007)
Overview Research Goals Test the hypothesis that North American (Ontario) Ginseng facilitates erectile function and sexual behavior: 1. In healthy male rats 2. In diabetic male rats
Objectives – Current study • Investigate the effects of Ontario ginseng on sexual behavior and erectile function in healthy, adult male rats • Determine the effects of ginseng on anxiety and other non-sexual effects in healthy male rats. • Determine if ginseng acts centrally, peripherally, or both.
Animal Model • Rat • Long Evans • Hooded rat: will also be used for diabetic model (Zucker Fatty rat) • Show more psychogenic erections than albino rats
Ontario ginseng • Composite from 5 Ontario farms • Tested for heavy metal and herbicide levels, as well as adulteration • Delivery: Oral by gavage • daily 2 – 4 hours after lights off. • Dosages: • aqueous extract (125 or 250 mg/kg) or saline • ethanol extract (125 or 250 mg/kg) or saline
Timeline Week 6 Week 3 Week 4 Week 5
Reward/Aversion Aqueous extract was not rewarding or aversive Ethanol extract is rewarding Conditioned Place Preference Aqueous n = 8, Ethanol n = 10
Anxiety Aqueous or ethanol extracts did not cause or reduce anxiety Elevated Plus Maze Open Field Test Aqueous n = 8
Overview NA ginseng does not cause aversion nor anxiety Therefore: any effects on sexual behaviour will not be secondary to these influences.
Sexual Behavior Aqueous extract slightly increased erectile function Aqueous n = 8
Sexual Behavior Ethanol extract did not affect erectile function but increased motivation. Ethanol n = 10
Non-contact Erections Aqueous extract did not affect non-contact erections (psychogenic erections) Ethanol extract also had no effect Aqueous n = 8, Ethanol n = 10
Conclusions – Healthy rats • Aqueousextract: increase copulation efficiency; suggestive of increased erectile function during mating. • Ethanolextract: decreases mount and intromission latency; suggestive of increased sexual arousal. A trend exists of decreased mount frequency. • No effects on any other parameter of sexual behaviour or erectile function induced by distal cues.
Ongoing studies • Determine sites of action: central or peripheral • Peripheral: • Erectile tissues (quantitative PCR, NO activity assays) • Central Nervous System: • Neural activity mapping to visualize neurons activated by ginseng following acute and chronic administration
Future studies • Determine effects of Ginseng on sexual/erectile function in rat model of diabetes • Zucker rats have a mutated leptin gene • Most are diabetic displaying phenotypes similar to type 2 diabetes patients: • Obesity • Insulin resistance • Impaired vasodilation • Hypertension (Kasiske et al 1992)
Future Studies • Test effects of both extracts on erectile function in Zucker Fatty rats: • Sexual behaviour • Intercavernous pressure recordings
Thank you!_____________________________________________________________________________________________________Dr. Coolen, Dr. Lui, Dr. Hammond, Dr. FengOntario Ministry of Research and Innovation Have you had your Ginseng today?