Evolving ideas about the male refractory period

Repeated sexual intercourse as a coping strategy for men with premature ejaculation

BACKGROUND

Patients with premature ejaculation (PE) are often concerned and distressed about their sexual performance. Hence, they may be more willing to exploit their refractory period to employ sexual coping strategies in order to improve their unsatisfactory sexual intercourse compared with patients without PE.

AIM

The study sought to verify the sexual coping strategies of patients with PE in the daily sexual activities.

METHODS

We included both patients with PE and individuals without PE and analyzed their sexual behaviors and attitudes by means of detailed interviews and questionnaires.

OUTCOMES

The main outcomes were perceived intravaginal ejaculatory latency time recording, Premature Ejaculation Diagnostic Tool score, and sexual frequency, attitudes, and behavior log.

RESULTS

A total of 182 young patients with PE (age 31.2 ± 6.2 years) and 92 individuals without PE (age 30.7 ± 5.1 years) were included in the study. A total of 53.3% of patients with PE vs 17.4% of individuals without PE reported engaging in multiple sexual intercourse sessions within a single day in the past 4 weeks. PE patients who engaged in multiple intercourse sessions displayed better performance during the second attempt but performed poorly compared with individuals without PE. Scores for the first attempt in PE vs second attempt in individuals with PE vs without PE were the following: intravaginal ejaculatory latency time, 2.4 ± 1.6 vs 4.8 ± 5.7 vs 9.9 ± 9.4 (P < .001); Premature Ejaculation Diagnostic Tool, 14.9 ± 3.1 vs 12.7 ± 4.8 vs 5.2 ± 2.5 (P < .001); satisfaction, 2.9 ± 1.0 vs 3.1 ± 0.8 vs 3.7 ± 1.4 (P < .001). A total of 57.1% of patients held a negative attitude toward precoital masturbation, for reasons such as a reduced sexual desire (21.2%), the belief that masturbation is harmful (17.6%), concerns about erectile function (15.7%), fatigue (9.8%), and other mixed reasons (35.3%).

CLINICAL IMPLICATIONS

Engaging in multiple intercourse sessions within a day is more common among the young PE population, and using precoital masturbation as a coping strategy is not universally applicable among patients with PE.

STRENGTHS AND LIMITATIONS

This is the first study to explore symptom-coping strategies in patients with PE compared with individuals without PE. However, the conclusions cannot be generalized to the entire male population.

CONCLUSION

Patients with PE, compared with individuals without PE, are more inclined to engage in multiple sexual intercourse sessions within a single sexual session, likely in an attempt to compensate for their first unsatisfactory sexual encounter. Moreover, the majority of patients with PE here studied hold a negative attitude toward using precoital masturbation as a coping strategy for symptoms.

Sexual Function and Satisfaction in the Context of Obesity

PURPOSE OF REVIEW

Sexual dysfunction is commonly associated with overweight/obesity, but the underlying physiological and psychosocial mechanisms are not fully understood. This review contextualizes the obesity-sexual (dys)function relationship, describes recent insights from the medical and social science literature, and suggests opportunities for continued research.

RECENT FINDINGS

Although sexual dysfunction has been historically evaluated as a consequence/outcome of obesity, it is increasingly considered as a harbinger of future metabolic comorbidities, including type 2 diabetes and cardiovascular disease. Body image dissatisfaction is a consistent predictor for lower sexual satisfaction across BMI categories, likely mediated by cognitive distraction during partnered sex. To fully capture the relationship between obesity and sexual dysfunction, multidisciplinary research approaches are warranted. While clinically significant weight loss tends to improve sexual functioning for women and men, higher body image satisfaction may independently promote sexual function and satisfaction without concomitant weight loss.

D. H. Lawrence and Sexuality: Reassessing the Novels

As a writer of fiction, D. H. Lawrence spent his career maneuvering between heterosexual and homosexual preferences. In order to make a living, he needed to use mainstream publishers. They encouraged his bold work but only if he censored it. What especially interested Lawrence were the differences between male and female orgasm-not just the mechanics but their meaning. Over his career (1910-1930) his views on orgasm evolved from simple release, to ambivalent forms of lust, to a challenging separation of responses: unfathomable silence for males and articulate expression for females. The sexes are privileged differently, and the categorical separation that Lawrence discovers is a revelation. This essay analyzes five of his most famous novels, from Sons and Lovers to Lady Chatterley's Lover, and, based on revisions in his texts, reaches conclusions that differ from those most readers have held. In revising, Lawrence came to reshape his characters' responses into complex, often-coded narratives.

Sex, ducks, and rock "n" roll: Mathematical model of sexual response

In this paper, we derive and analyze a mathematical model of a sexual response. As a starting point, we discuss two studies that proposed a connection between a sexual response cycle and a cusp catastrophe and explain why that connection is incorrect but suggests an analogy with excitable systems. This then serves as a basis for derivation of a phenomenological mathematical model of a sexual response, in which the variables represent levels of physiological and psychological arousal. Bifurcation analysis is performed to identify stability properties of the model's steady state, and numerical simulations are performed to illustrate different types of behavior that can be observed in the model. Solutions corresponding to the dynamics associated with the Masters-Johnson sexual response cycle are represented by "canard"-like trajectories that follow an unstable slow manifold before making a large excursion in the phase space. We also consider a stochastic version of the model, for which spectrum, variance, and coherence of stochastic oscillations around a deterministically stable steady state are found analytically, and confidence regions are computed. Large deviation theory is used to explore the possibility of stochastic escape from the neighborhood of the deterministically stable steady state, and the methods of an action plot and quasi-potential are employed to compute most probable escape paths. We discuss implications of the results for facilitating better quantitative understanding of the dynamics of a human sexual response and for improving clinical practice.

Male fattening is related to increased seminal quality of squirrel monkeys (Saimiri collinsi): Implications for sperm competition

Saimiri are neotropical primates with seasonal reproduction, males develop a seasonal fattening condition that has been suggested as a pre-copulatory sexual selection strategy. Furthermore, females mate with multiple males in the same season. This could also favor the evolution of a postcopulatory sexual strategy by sperm competition. In this study, we tested the hypothesis that there is a relationship between the fatted condition and advantageous seminal characteristics in Saimiri collinsi and evaluated its implications for sperm competition. Adult males (N = 10), aged 5-15 years, housed in mixed or only-male groups, were analyzed from June, 2015 to July, 2016. Measurements of weight, axilla, and arm skinfold, and testicular volume were taken monthly, and semen was collected by electroejaculation. A fattening index was developed to quantify and identify fatted males, biometrics, and seminal parameters were compared between the non-fatted and fatted conditions. The fatted males present a larger testicular volume. This is related to the increase in spermatogenic activity necessary to sustain a high ejaculation frequency during the mating season. An increase in seminal volume and in frequency of semen coagulation were detected in fatted males, advantages related to sperm protection in the female reproductive tract. Age and social context were not significant sources of variation for both morphological and seminal traits. A decrease in response from the fatted males in obtaining semen and an increase in the frequency of azoospermic ejaculates were observed. These unexpected results may be due to intense reproductive activities in a short period. The fattening phenomenon has many implications in the sexual selection of squirrel monkeys, and they are still not entirely unveiled. Our results corroborate the idea that, in S. collinsi, the fatted male condition is related to sexual selection, and we found evidence suggesting it may be also expressed by a post-copulatory component, sperm competition.

Exploring Male Multiple Orgasm in a Large Online Sample: Refining Our Understanding

BACKGROUND

The scientific literature on multiple orgasm in males is small. There is little consensus on a definition, and significant controversy about whether multiple orgasm is a unitary experience.

AIMS

This study has 2 goals: (i) describing the experience of male multiple orgasm; (ii) investigating whether there are different profiles of multiple orgasm in men.

METHODS

Data from a culturally diverse online convenience sample of 122 men reporting multiple orgasm were collected. Data reduction analyses were conducted using principal components analysis (PCA) on 13 variables of interest derived from theory and the existing literature. A K-means cluster analysis followed, from which a 4-cluster solution was retained.

RESULTS

While the range of reported orgasms varied from 2 to 30, the majority (79.5%, N = 97) of participants experienced between 2 and 4 orgasms separated by a specific time interval during which further stimulation was required to achieve another orgasm. Most participants reported maintaining their erections throughout and ejaculating with every orgasm. Age was not a significant correlate of the multiple orgasm experience which occurred more frequently in a dyadic context. Four different profiles of multiorgasmic men were described.

STRENGTHS & LIMITATIONS

This study constitutes a rare attempt to collect systematic self-report data concerning the experience of multiple orgasm in a relatively large sample. Limitations include the lack of validated measures, memory bias associated with self-reported data and retrospective designs, the lack of a control group and of physiological measurement.

CONCLUSION

Our study suggests that multiple orgasm in men is not a unitary phenomenon and sets the stage for future self-report and laboratory study. Griffin-Mathieu G, Berry M, Shtarkshall RA, Amsel R, Binik YM, Gérard M. Exploring Male Multiple Orgasm in a Large Online Sample: Refining Our Understanding. J Sex Med 2021;XX:XXX-XXX.

No evidence for prolactin's involvement in the post-ejaculatory refractory period

In many species, ejaculation is followed by a state of decreased sexual activity, the post-ejaculatory refractory period. Several lines of evidence have suggested prolactin, a pituitary hormone released around the time of ejaculation in humans and other animals, to be a decisive player in the establishment of the refractory period. However, data supporting this hypothesis is controversial. We took advantage of two different strains of house mouse, a wild derived and a classical laboratory strain that differ substantially in their sexual performance, to investigate prolactin's involvement in sexual activity and the refractory period. First, we show that there is prolactin release during sexual behavior in male mice. Second, using a pharmacological approach, we show that acute manipulations of prolactin levels, either mimicking the natural release during sexual behavior or inhibiting its occurrence, do not affect sexual activity or shorten the refractory period, respectively. Therefore, we show compelling evidence refuting the idea that prolactin released during copulation is involved in the establishment of the refractory period, a long-standing hypothesis in the field of behavioral endocrinology.

Modeling Human Sexual Motivation in Rodents: Some Caveats

Sexual behavior is activated by motivation. An overwhelming majority of experimental studies of the intricacies of sexual motivation has been performed in rodents, most of them in rats. Sometimes it is desirable to generalize results obtained in this species to other species, particularly the human. It is hoped that studies of the neurobiology of rodent sexual behavior may shed light on the central nervous mechanisms operating in the human, and the search for efficient pharmacological treatments of human sexual dysfunctions relies partly on studies performed in rodents. Then the issue of generalizability of the rodent data to the human becomes crucial. We emphasize the importance of distinguishing between copulatory acts, behavior involving the genitals, and the preceding event, the establishment of physical contact with a potential mate. Comparisons between the structure of copulatory behavior in rats and humans show abysmal differences, but there may be some similarity in the underlying mechanisms. The endocrine control of sex behavior is shortly mentioned, and we also compare the effects of the few drugs known to affect both rodent and human copulatory behavior. The stimuli activating sexual motivation, often called desire in the human literature, are examined, and the sexual approach behaviors in rats and humans are compared. There is a striking similarity between these species in how these behaviors respond to drugs. It is then shown that the intensity of sexual approach is unrelated to the intensity of copulatory behavior. Even though the approach is a requisite for copulation, an activity that requires at least two individuals in close physical contact, these two aspects of sexuality do not covary. This is similar to the role of the testosterone in men and male rats: although the hormone is needed for sex behavior, there is no correlation between serum testosterone concentration and the intensity of copulation. It is also pointed out that human sexual behavior is mostly determined by social conventions, whereas this is not the case in rats and other rodents. It is concluded that some observations in rats can be generalized to the human, but extreme caution must be exercised.

Association Between Post-Ejaculatory Refractory Time (PERT) and Premature Ejaculation (PE)

INTRODUCTION

Patients with premature ejaculation (PE) often complain of difficulty in having second erection, which is not yet investigated using scientific methodology.

AIM

Evaluation of the association between post-ejaculation refractory time (PERT) with PE by comparing PERT in premature ejaculators with their age-matched control subjects.

METHODS

After ethical committee approval and written informed consent from the participants were obtained, men in a monogamous stable sexual relationship and reporting PE were recruited into the study. Sexually active, matched control subjects were recruited for comparison. Exclusion criteria were erectile dysfunction, diabetes mellitus, cardiovascular diseases, hypogonadism, psychiatric conditions, instrumentation of the genitourinary tract, genitourinary anomalies, and genitourinary infections. Both the premature ejaculators and their control subjects were evaluated with the PE diagnostic tool before initiation of the study. They were asked to record their IELT and PERT over 4 weeks. The statistical analysis was done to obtain descriptive statistics, namely, mean and SD, paired t-tests, and logistic regression analysis. P < .001 was considered significant.

MAIN OUTCOME MEASURE

There was a statistically significant association between prolonged PERT and PE in patients with PE compared with their age-matched control subjects.

RESULTS

102 premature ejaculators and an equal number of matched control subjects were evaluated from January 2016-December 2017. The average PERT in premature ejaculators and control subjects was 330 ± 296.63 minutes and 105.64 ± 98.59 minutes, respectively (P < .0001). Increasing age was associated with increasing PERT. PE was more common in patients when PERT exceeded a threshold of 590 minutes.

CLINICAL IMPLICATIONS

Until now, the association between PE and PERT with matched-pair analysis was not reported. Our study addresses this association, which can add a new paradigm in the evaluation and management of PE.

STRENGTH & LIMITATIONS

The association between PE and prolonged PERT using a statistically appropriate, adequately powered methodology is the strength of the study. The inability to address the causal association between prolonged PERT and PE because of the paucity of evidence at present is the limitation of the study. We believe that the results of this study could trigger further research into such an association, so the mystery of such an association can be unraveled.

CONCLUSIONS

The association between prolonged PERT and PE, as seen in our study, is a finding, that needs further research to establish a causal association. However, reporting such an association is necessary because it is contrary to the present understanding. Bhat GS, Shastry A. Association Between Post-Ejaculatory Refractory Time (PERT) and Premature Ejaculation (PE). J Sex Med 2019;16:1364-1370.

Genital vibration for sexual function and enhancement: a review of evidence

Vibration, as provided by a genital vibrator, is commonly regarded as a tool to enhance sexual pleasure and in modern day society falls under the category of a sex toy. However, the vibrator was not originally intended to be a toy, and its benefits reach far beyond that of a plaything. This article is a narrative review of the current evidence regarding the use of vibratory stimulation for the treatment of sexual dysfunction and/or sexual and relationship enhancement. The literature indicates that vibratory stimulation has evidence-based support for the treatment of erectile dysfunction, ejaculatory dysfunction and anorgasmia. Vibratory stimulation is positively correlated with increased sexual desire and overall sexual function. It has also shown benefit for sexual arousal difficulties and pelvic floor dysfunction. Though definitive evidence is lacking, genital vibration is a potential treatment for sexual dysfunction related to a wide variety of sexual health concerns in men and women.

Normal male sexual function: emphasis on orgasm and ejaculation

Orgasm and ejaculation are two separate physiological processes that are sometimes difficult to distinguish. Orgasm is an intense transient peak sensation of intense pleasure creating an altered state of consciousness associated with reported physical changes. Antegrade ejaculation is a complex physiological process that is composed of two phases (emission and expulsion), and is influenced by intricate neurological and hormonal pathways. Despite the many published research projects dealing with the physiology of orgasm and ejaculation, much about this topic is still unknown. Ejaculatory dysfunction is a common disorder, and currently has no definitive cure. Understanding the complex physiology of orgasm and ejaculation allows the development of therapeutic targets for ejaculatory dysfunction. In this article, we summarize the current literature on the physiology of orgasm and ejaculation, starting with a brief description of the anatomy of sex organs and the physiology of erection. Then, we describe the physiology of orgasm and ejaculation detailing the neuronal, neurochemical, and hormonal control of the ejaculation process.

Caenorhabditis elegans male sensory-motor neurons and dopaminergic support cells couple ejaculation and post-ejaculatory behaviors

The circuit structure and function underlying post-coital male behaviors remain poorly understood. Using mutant analysis, laser ablation, optogenetics, and Ca²⁺ imaging, we observed that following C. elegans male copulation, the duration of post-coital lethargy is coupled to cellular events involved in ejaculation. We show that the SPV and SPD spicule-associated sensory neurons and the spicule socket neuronal support cells function with intromission circuit components, including the cholinergic SPC and PCB and the glutamatergic PCA sensory-motor neurons, to coordinate sex muscle contractions with initiation and continuation of sperm movement. Our observations suggest that the SPV and SPD and their associated dopamine-containing socket cells sense the intrauterine environment through cellular endings exposed at the spicule tips and regulate both sperm release into the hermaphrodite and the recovery from post-coital lethargy.

DOI:http://dx.doi.org/10.7554/eLife.02938.001

The nematode worm, C. elegans, is roughly 1 mm long, made up of around 1000 cells and has two sexes: male and hermaphrodite. Hermaphrodite worms produce both eggs and sperm and can self-fertilize to generate around 300 offspring each time. Fertilization by a male, on the other hand, results in three times as many progeny and introduces genetic diversity into the population. However, it also reduces the lifespan of the hermaphrodite.

Mating also incurs a cost for males: it requires a lot of energy, which prevents male works from engaging in other activities, such as feeding, and it also increases their risk of predation. In many species, including C. elegans, the frequency with which a male can mate is limited by a period of reduced mating drive and ability that follows each instance of successful mating. However, the molecular and cellular basis of this ‘refractory period’ remains largely unclear.

Using a range of techniques, LeBoeuf et al. have now identified the circuits that regulate male mating behavior in C. elegans. When male worms were introduced into a Petri dish containing 15 hermaphrodites, most males initiated mating within about 2 min. The length of the refractory period varied between worms, but averaged roughly 12 min. This consisted of a period of disinterest, in which males did not approach hermaphrodites, followed by a period in which males attempted mating but were slower and less efficient, suggesting that the neural circuits controlling mating behaviors had yet to recover completely.

Males with longer refractory periods produced more progeny in their second mating than those with shorter refractory periods, suggesting that the interval also enables males to replenish their sperm levels. Further experiments revealed that a chemical transmitter called dopamine promotes ejaculation and then immediately reduces the worm's activity levels, giving rise to the refractory period.

By enforcing a delay between matings, the refractory period may also increase the likelihood that successive matings will be with different hermaphrodites, helping to maximize the number and diversity of offspring. Some aspects of the neural circuitry that controls the refractory period in C. elegans resemble those seen in mammals, suggesting that insights gained from an animal with 1000 cells could also be relevant to more complex species.

DOI:http://dx.doi.org/10.7554/eLife.02938.002