Melanocortin 4 receptor signaling in Sim1 neurons permits sexual receptivity in female mice

Introduction

Female sexual dysfunction affects approximately 40% of women in the United States, yet few therapeutic options exist for these patients. The melanocortin system is a new treatment target for hypoactive sexual desire disorder (HSDD), but the neuronal pathways involved are unclear.

Methods

In this study, the sexual behavior of female MC4R knockout mice lacking melanocortin 4 receptors (MC4Rs) was examined. The mice were then bred to express MC4Rs exclusively on Sim1 neurons (tbMC4RSim1 mice) or on oxytocin neurons (tbMC4ROxt mice) to examine the effect on sexual responsiveness.

Results

MC4R knockout mice were found to approach males less and have reduced receptivity to copulation, as indicated by a low lordosis quotient. These changes were independent of body weight. Lordosis behavior was normalized in tbMC4RSim1 mice and improved in tbMC4ROxt mice. In contrast, approach behavior was unchanged in tbMC4RSim1 mice but greatly increased in tbMC4ROxt animals. The changes were independent of melanocortin-driven metabolic effects.

Discussion

These results implicate MC4R signaling in Oxt neurons in appetitive behaviors and MC4R signaling in Sim1 neurons in female sexual receptivity, while suggesting melanocortin-driven sexual function does not rely on metabolic neural circuits.

Treatment of women's sexual dysfunction using Apium graveolens L. Fruit (celery seed): A double-blind, randomized, placebo-controlled clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional manuscripts refer to plants such as Apium graveolens L. Fruit (celery seed), which could be used to improve sexual function among women. Since that time, local herbal shops in Iran continue to provide this herb as a natural aphrodisiac product.

AIM OF THE STUDY

This study aimed to evaluate the efficacy and safety of celery seed for the treatment of female sexual dysfunction.

METHODS AND MATERIALS

In this parallel, randomized, double-blinded clinical trial, 80 women were assigned to receive either 500 mg of celery seed or placebo 3 times a day for a period of 6 weeks (n = 40 per group). The female sexual function index (FSFI) questionnaire was used to evaluate women's sexual function before and after treatment.

RESULTS

At the end of the sixth week, an improvement in the total FSFI score was significantly greater in celery seed-treated women than those receiving the placebo (P < 0.001). Increased total FSFI score is mainly contributed by improvement in the sexual desire (p < 0.001), arousal (p < 0.001), lubrication (p < 0.001), and pain (p = 0.033) domains at the endpoint of study. No serious side effects were noticed in both groups during the study period.

CONCLUSION

It seems that celery seed improved sexual function in women and could be used as a safe, well-tolerated, and effective herbal medicine in women with sexual dysfunction.

The Effect of Korean Red Ginseng on Sexual Function in Premenopausal Women: Placebo-Controlled, Double-Blind, Crossover Clinical Trial

This study investigated whether Korean red ginseng (KRG) extracts could improve sexual function in premenopausal women. Forty-one premenopausal women participated in this placebo-controlled, double-blind, and crossover clinical study with administration of either three ginseng capsules (1 g per capsule) or placebo daily. After 8 weeks of medication of KRG or placebo, medication was changed for the subjects to placebo or KRG after 2 weeks of washout period. The efficacy of KRG extracts was measured by using Female Sexual Function Index (FSFI). Results. Twenty-three women completed the study. Total FSFI scores increased after KRG treatment (from 20.13 ± 2.87 to 23.98 ± 4.10, p = 0.015) and placebo treatment (from 20.06 ± 2.64 to 23.78 ± 3.28, p = 0.003). However, this change was not significantly different between the two groups (p = 0.702). KRG treatment significantly improved sexual desire, arousal, orgasm, and satisfaction domains; however, there was no treatment effect compared with placebo. There was a case of gastric discomfort after taking KRG extracts. Oral administration of KRG extracts improved sexual function in premenopausal women; however, there were no statistical significant changes compared to placebo. It implies that KRG extracts have a substantial placebo effect in premenopausal women with sexual dysfunction.

An update on sexual function and dysfunction in women

Sexual function of women can be affected by many factors resulting in female sexual dysfunction (FSD). Sexual dysfunction is a common problem among women of all ages and has negative effects not only on their quality of lives but also on the sexual function and quality of life of their partners. It can also affect mental health of the entire family and society. Regarding the multidimensional nature of female sexual dysfunction and considering its consequences, this condition needs to be recognised in its early stages in order to prevent future consequences and impacts. This article discusses biopsychosocial aspect of female sexual function, classifications and risk factors of female sexual dysfunction and investigates current approaches to identify and treat this problem.

Review of low libido in women

Low libido is the most frequently reported sexual dysfunction. This is an important and complex problem with multiple causes. At present the interpretation of data on this topic remains a challenge, as the subject population is diverse and various tools are used in assessment. Coupled with this, several definitions are in use with differing emphasis on distress resulting from this state. Developments in the understanding of psychopharmacology are shedding light on the pathways involved in normal sexual response and these are being utilized in the development of treatments. This article reviews the current definitions, aetiology and treatment options and explores the recent developments in low libido in women.