Neuronal nitric oxide synthase activity mediates Lycium barbarum polysaccharides-enhanced sexual performance without stimulating noncontact erection in rats

• Published in: Psychopharmacology Vol. 236; no. 4; pp. 1293 - 1301
• Main Authors: Huang, Andy C., Wu, Jia-Min, Chang, Ya-Han, Dubey, Navneet Kumar, Chiu, Allen W., Yeh, Chien-Yu, Tsai, Tung-Hu, Yeh, Kuei-Ying
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-04-2019; Springer; Springer Nature B.V
• Subjects: Animals; Biomedical and Life Sciences; Biomedicine; Brain; Copulation; Drugs, Chinese Herbal - pharmacology; Ejaculation; Enzyme Activation - drug effects; Enzyme Activation - physiology; Female; Lycium barbarum; Male; Neurons; Neurons - drug effects; Neurons - enzymology; Neurosciences; Nitric Oxide; Nitric Oxide Synthase Type I - metabolism; Nitric-oxide synthase; Nitrogen oxides; Original Investigation; Paraventricular Hypothalamic Nucleus - drug effects; Paraventricular Hypothalamic Nucleus - enzymology; Paraventricular nucleus; Penile Erection - drug effects; Penile Erection - physiology; Penis; Pharmacology/Toxicology; Polysaccharides; Preoptic area; Preoptic Area - drug effects; Preoptic Area - enzymology; Psychiatry; Rats; Rats, Long-Evans; Rodents; Saccharides; Sexual behavior; Sexual Behavior, Animal - drug effects; Sexual Behavior, Animal - physiology; Sexual disorders; Testis - drug effects; Testis - enzymology; Noncontact erection; Paraventricular nucleus; polysaccharide; Medial preoptic area; Sexual behavior; nNOS; Lycium barbarum polysaccharide
• ISSN: 0033-3158; 1432-2072
• DOI: 10.1007/s00213-018-5141-z

Rationale
Lycium barbarum
polysaccharide (LBP) is known to promote reproductive functions. However, its role in noncontact erection (NCE) of penis initiated by brain regions including medial preoptic area (MPOA) and paraventricular nucleus (PVN) regions responsible for sexual behavior has not been investigated.
Objectives
Therefore, this study initially investigated the effects of LBP on male sexual function, and subsequently, the mechanistic insight was investigated through assessing the expression of neuronal nitric oxide synthase (nNOS) in the MPOA and PVN.
Methods
The adult male rats were treated with 100 mg/kg of LBP or vehicle by oral gavage. Before and after 14 days of treatment, copulatory behavior and noncontact erection (NCE) were recorded. After the last behavioral test, the brain was isolated to measure nNOS expression in the MPOA and PVN.
Results
Data showed that LBP treatment significantly increased both the frequencies of intromission as well as ejaculation, compared to the control group. Whereas, a reduced post-ejaculatory interval was observed compared to same group on day 0. Furthermore, the treatment led to an increased intromission ratio, inter-intromission interval, and the number of MPOA nNOS-immunoreactive cells (nNOS-ir). Additionally, a significantly positive correlation between ejaculation frequency and MPOA nNOS-ir cells was recorded. Of note, LBP treatment had no effects on NCE and PVN nNOS-ir expression.
Conclusion
These findings suggest that LBP enhances sexual behavior through increased nNOS expression in the MPOA in male rats.