A dual physiological character for sexual function: libido and sexual pheromones

Measuring Sexual Intelligence for Evaluating Sexual Health

The current paper reports four consecutive studies that were conducted to link sexual health with a new construct of sexual intelligence by developing and validating a new scale to measure sexual intelligence. Sexual intelligence was defined as "the ability to perceive, understand and respond to sexual needs and desires in a personal and social context." Sexual Intelligence Scale (SIS), comprising of 8 items in English and 2 factors (sexual knowledge & sexual behavior), was developed and validated by involving 959 respondents in the process of 4 consecutive studies. The validity of SIS was tested step by step for its face, content, factorial, convergent, discriminant, and predictive validities. The reliability was measured through internal consistency and item-total & item-scale correlations. The study found significantly higher levels of sexual intelligence in men as compared to women. Sexual intelligence, moreover, had significant positive correlations with age, education, emotional intelligence, social intelligence, sexual health, and satisfaction with life. Sexual health was linked with sexual intelligence and the SIS was accepted as a reliable and valid tool to measure sexual intelligence.

Prostate cancer in sexual minorities and the influence of HIV status

Prostate cancer is the second most common cause of cancer-related death in men in the USA, but the effect of prostate cancer diagnosis and treatment on men in a sexual minority group, including men who have sex with men and transgender women, is poorly understood. Efforts to study this population are complicated, as cancer registries do not routinely collect information on sexual orientation. As a result, epidemiological data regarding this population have come from small studies that have included disparate rates of prostate cancer screening, diagnosis and treatment. Qualitative studies indicate that prostate cancer is experienced differently by sexual minorities, with distinct health-care needs that arise owing to differences in sexual practices, social support systems and relationships with the medical community. Notably, sexual minorities have been reported to experience poorer health-related quality of life outcomes than heterosexual men, and tend to have less robust social support systems, experience increased psychological distress caused by sexual dysfunction (areas of which are unmeasured after treatment), experience isolation within the health-care system and express increased levels of dissatisfaction with treatment. The incidence of prostate cancer actually seems to be decreased in men from sexual minorities living with HIV, despite there being no differences in screening and treatment, with poor cancer-specific mortality. Although the literature on patients with prostate cancer in men from sexual minority groups has historically been sparse, peer-reviewed research in this area has grown considerably during the past decade and has become an important field of study.

Neuroanatomy and function of human sexual behavior: A neglected or unknown issue?

INTRODUCTION

Sexual desire, arousal, and orgasm are mediated by complex, yet still not fully understood, interactions of the somatic and autonomic nervous systems operating at the central and peripheral levels. Disruption of endocrine, neural, or vascular response, caused by aging, medical illness, neurological diseases, surgery, or drugs, can lead to sexual dysfunctions, thus significantly affecting patients' quality of life.

PURPOSE

This narrative review aims at characterizing the involvement of the central nervous system in human sexual behavior.

METHODS

A literature search was conducted using PubMed in its entirety up to June 2018, analyzing the studies dealing with the neurobiological and neurophysiological basis of human sexuality.

RESULTS

Sexual behavior is regulated by both subcortical structures, such as the hypothalamus, brainstem, and spinal cord, and several cortical brain areas acting as an orchestra to finely adjust this primitive, complex, and versatile behavior. At the central level, dopaminergic and serotonergic systems appear to play a significant role in various factors of sexual response, although adrenergic, cholinergic, and other neuropeptide transmitter systems may contribute as well.

CONCLUSIONS

Providing healthcare professionals with information concerning sexual behavior may overcome useless and sometimes dangerous barriers and improve patient management, since sexual well-being is considered one of the most important aspects of one's quality of life.

Aromatherapy: Activating olfactory calcium-sensing receptors impairs renal hemodynamics via sympathetic nerve-mediated vasoconstriction

AIM

This study determines whether the activation of olfactory calcium-sensing receptor initiates a sympathetic activation-dependent neurovascular reflex subsequently contributing to renal hemodynamic depression.

METHODS

Immunohistochemistry and nose-loading calcium-sensitive dye were used to explore the location and function of calcium-sensing receptor on the olfactory sensory neuron. The renal sympathetic nervous activity, renal hemodynamics and the microcirculation of kidney, liver and intestine were evaluated after liquid-phase intranasal administrations of saline, lidocaine, calcium-sensing receptor agonists and antagonist in sham and bilateral renal denervated rats. Real-time renal glomerular filtration rate was measured by a magnetic resonance renography.

RESULTS

Calcium-sensing receptors were expressed on the cilia the olfactory sensory neuron and their activation depolarized olfactory sensory neuron and induced the calcium influx in the terminal side on olfactory glomeruli. Activating olfactory calcium-sensing receptors significantly increased arterial blood pressure and renal sympathetic nervous activities and subsequently decreased renal blood flow, renal, hepatic and enteral microcirculation. Cotreatments with calcium-sensing receptor antagonist or lidocaine inhibited these physiological alterations. The renal hemodynamic depressions by olfactory calcium-sensing receptor activation were significantly blocked by bilateral renal denervation. The intranasal manganese administration decreased the glomerular filtration rate.

CONCLUSION

Calcium-sensing receptor acts as a functional chemosensory receptor on olfactory sensory neuron, and its activation causes the global sympathetic enhancement contributing to systematic vasoconstriction and subsequently depresses renal blood flow and glomerular filtration rate. These data implicate a possibly clinical aspect that several environmental stimuli may activate olfactory calcium-sensing receptors to evoke a sympathetic nervous system-mediated neurovascular reflex to depress renal hemodynamics.

Molecular basis of androgen action on human sexual desire

Reproduction is a fundamental process for the species maintenance and the propagation of genetic information. The energy expenditure for mating is overtaken by motivational stimuli, such as orgasm, finely regulated by steroid hormones, gonadotropins, neurotransmitters and molecules acting in the brain and peripheral organs. These functions are often investigated using animal models and translated to humans, where the androgens action is mediated by nuclear and membrane receptors converging in the regulation of both long-term genomic and rapid non-genomic signals. In both sexes, testosterone is a central player of this game and is involved in the regulation of sexual desire and arousal, and, finally, in reproduction through cognitive and peripheral physiological mechanisms which may decline with aging and circadian disruption. Finally, genetic variations impact on reproductive behaviours, resulting in sex-specific effect and different reproductive strategies. In this review, androgen actions on sexual desire are evaluated, focusing on the molecular levels of interaction.

The ventral-hypothalamic input route: a common neural network for abstract cognition and sexuality

Classically, external receptors of the body transmit information from the environment to the cerebral cortex via the thalamus. This review explains and argues that only concrete external information is transmitted from peripheral receptors to the cortex via a thalamic route, while abstract and sexual external information are actually transmitted from peripheral receptors to the cortex through a cognitive hypothalamic route. Sexual function typically implies participation of two distinct partners, ensuring reproduction in many species including humans. Human sexual response involves participation of multiple (environmental, biological, psychological) kinds of stimuli and processing, so the understanding of sexual control and response supposes integration between the classical physiological mechanisms with the more complex processes of our 'mind'. Cognition and sexuality are two relational functions, which are dependent on concrete (colours, sounds, etc.) and/or abstract (gestures, facial expression, how you move, the way you say something seemingly trivial, etc.) environmental cues. Abstract cues are encoded independent of the specific object features of the stimuli, suggesting that such cues should be transmitted and interpreted within the brain through a system different than the classical thalamo-cortical network that operates on concrete (material) information. Indeed, data show that the cerebral cortex is capable of interpreting two distinct (concrete and abstract) formats of information via distinct and non-compatible brain areas. We expand upon this abstract-concrete dichotomy of the brain, positing that the two distinct cortical networks should be uploaded with distinct information from the environment via two distinct informational input routes. These two routes would be represented by the two distinct routes of the ascending reticular activating system (ARAS), namely the classical/dorsal thalamic input route for concrete information and the ventral hypothalamic input route for abstract cognition and sexuality. Physiologically, the hypothalamic (dual-autonomic) route of the ARAS that processes abstract and sexual information is incompatible with the thalamic (somatic) route of the ARAS that processes concrete information, such that the two distinct routes would be needed to support the mind processes (awareness, consciousness, sexuality) through their own informational inputs from the environment. Informationally, the concrete external data are differentiated from abstract and sexual external data, so that they should be transmitted to cortex through distinct input routes. Pathologically, the hardware and/or software impairments of the hypothalamic default-mode network generate disturbed messages within the brain (related to information transmitted on this route), laying at the basis of mental and sexual disorders. The novel conceptualisations presented in the present paper help address issues surrounding the mind-brain dichotomy and, in doing so, suggest new possible avenues for exploration in the treatment and interventions for cognitive and sexual problems.

Pheromonal bile acid 3-ketopetromyzonol sulfate primes the neuroendocrine system in sea lamprey

BACKGROUND

Vertebrate pheromones are known to prime the endocrine system, especially the hypothalamic-pituitary-gonadal (HPG) axis. However, no known pheromone molecule has been shown to modulate directly the synthesis or release of gonadotropin releasing hormone (GnRH), the main regulator of the HPG axis. We selected sea lamprey (Petromyzon marinus) as a model system to determine whether a single pheromone component alters the output of GnRH.Sea lamprey male sex pheromones contain a main component, 7α, 12α, 24-trihydroxy-5α-cholan-3-one 24-sulfate (3 keto-petromyzonol sulfate or 3kPZS), which has been shown to modulate behaviors of mature females. Through a series of experiments, we tested the hypothesis that 3kPZS modulates both synthesis and release of GnRH, and subsequently, HPG output in immature sea lamprey.

RESULTS

The results showed that natural male pheromone mixtures induced differential steroid responses but facilitated sexual maturation in both sexes of immature animals (χ(2) = 5.042, dF = 1, p < 0.05). Exposure to 3kPZS increased plasma 15α-hydroxyprogesterone (15α-P) concentrations (one-way ANOVA, p < 0.05) and brain gene expressions (genes examined: three lamprey (l) GnRH-I transcripts, lGnRH-III, Jun and Jun N-terminal kinase (JNK); one-way ANOVA, p < 0.05), but did not alter the number of GnRH neurons in the hypothalamus in immature animals. In addition, 3kPZS treatments increased lGnRH peptide concentrations in the forebrain and modulated their levels in plasma. Overall, 3kPZS modulation of HPG axis is more pronounced in immature males than in females.

CONCLUSIONS

We conclude that a single male pheromone component primes the HPG axis in immature sea lamprey in a sexually dimorphic manner.

Preliminary study with bicalutamide in heterosexual and homosexual patients with prostate cancer: a possible implication of androgens in male homosexual arousal

OBJECTIVE

• Not only has a precise characterization of libido and sexual arousal in men as a central neural process been lacking, but the interactive role of gonadal hormones and sexual orientation in such processes has never been investigated. We investigate the relationships among sexual hormones, sexual arousal, and sexual orientation in men by comparing the self-reported sexual response of heterosexual and homosexual men with locally advanced prostate neoplasm, receiving the non-steroidal anti-androgen bicalutamide as monotherapy.

PATIENTS AND METHODS

• 29 Romanian men participated in this study: 17 heterosexual and 12 homosexual. Patients were undergoing treatment for prostate cancer consisting of a standard daily dose of 50 mg bicalutamide, a fast acting non-steroidal anti-androgen with action comparable to other anti-androgen drugs but with reportedly fewer sexual side effects. • Patients retrospectively provided information regarding their sexual functioning measured by the IIEF prior to commencing bicalutamide treatment. • Then, about five weeks later, patients were asked to prospectively provide information regarding their current sexual functioning while undergoing bicalutamide treatment.

RESULTS

• Overall IIEF scores as well as the Erectile Function, Orgasmic Function, Sexual Desire, and Overall Satisfaction subscales showed group, treatment, and group by treatment effects. • The Intercourse Satisfaction subscale showed group and group by treatment effects. • On most subscales, homosexual men showed lower functioning than heterosexual men, primarily in response to treatment with bicalutamide.

CONCLUSIONS

• Treatment with an anti-androgen in a clinical population of men undergoing therapy for prostate cancer affected homosexual men more than heterosexual men, although not all heterosexual men were unaffected. • These results are discussed in the context of dual sexual natures, a concept recently developed in the sexual literature. • Furthermore, these findings reiterate the importance of incorporating such variables as sexual orientation into studies investigating medical treatments on sexual response.