Facilitation of male sexual behavior in Syrian hamsters by the combined action of dihydrotestosterone and testosterone

Management Options for Premature Ejaculation and Delayed Ejaculation in Men

INTRODUCTION

Many men experience distressing issues regarding the timing of orgasm and ejaculation, such as premature ejaculation (PE) and delayed ejaculation (DE). Despite being highly prevalent, both PE and DE are poorly understood and present a management challenge for sexual medicine specialists.

AIM

To summarize existing data on the medical management of PE and DE.

METHODS

A comprehensive literature review pertaining to the management of PE and DE was conducted using PubMed and clinicaltrials.gov for data published up until May 2019. Our focus was on double-blind, placebo-controlled trials and meta-analyses of such studies.

MAIN OUTCOME MEASURE

Peer-reviewed studies on treatment options for PE and DE were critically analyzed for results and methodological rigor.

RESULTS

The peer-reviewed data on PE management continue to evolve. Psychotherapy, pharmacotherapy, and procedural interventions have all been associated with some degree of efficacy. A strong evidence base supports the off-label use of selective serotonin reuptake inhibitors and local anesthetics in PE given consistent increases in ejaculation latency time. Education and mental health assessments remain important components of PE management despite a dearth of peer-reviewed data on these interventions. Numerous treatment strategies have been evaluated for DE; limited data support psychotherapy, pharmacotherapy, and/or penile vibratory stimulation as management options.

CONCLUSION

A number of management options for PE or DE exist but none has been formally approved by the US Food and Drug Administration. New and novel treatments would be of great value in managing issues regarding the timing of ejaculation/orgasm. Martin-Tuite P, Shindel AW. Management Options for Premature Ejaculation and Delayed Ejaculation in Men. Sex Med Rev 2020; 8:473-485.

BDNF infusion into the MPN mag is sufficient to restore copulatory behavior in the castrated Syrian hamster

Testosterone plays a key role in the expression of male sex behavior by influencing cellular activity and synapses within the magnocellular medial preoptic nucleus (MPN mag), a sub-nucleus of the medial preoptic area (MPOA) in the Syrian hamster. Although the mechanisms underlying hormonally-induced synaptic plasticity in this region remain elusive, the data suggests that an increase in synaptic density may mediate testosterone's effects on copulation. As brain derived neurotrophic factor (BDNF) plays an integral role in regulating synaptic plasticity and gonadal steroids regulate the levels of BDNF, we hypothesize that BDNF may mediate the effects of gonadal hormones on copulatory behavior. To test this hypothesis, we infused BDNF or controls into the MPN mag of long-term castrates. Our results indicate that BDNF, but not the controls, restored copulatory behavior in castrated male Syrian hamsters. Furthermore, the rise of BDNF expression in the MPOA preceded the rise of synaptophysin following testosterone replacement in castrated males. These data are consistent with our hypothesis, implicating a role for BDNF in mediating testosterone's action on copulation and suggest that the delay in testosterone's restoration of copulation is, in part, due to the delay in the increase of BDNF and synaptophysin.

The drug treatment of delayed ejaculation

Delayed ejaculation (DE) is an uncommon and a challenging disorder to treat. It is often quite concerning to patients and it can affect psychosocial well-being. Here we reviewed how DE is treated pharmacologically .We also highlighted specific settings where drugs could be introduced to medical practice. Electronic databases were searched from 1966 to February 2016, including PubMed MEDLINE, EMBASE, EBCSO Academic Search Complete, Cochrane Systematic Reviews Database, and Google Scholar using key words; delayed ejaculation, retarded ejaculation, inhibited ejaculation, drugs, treatment, or pharmacology. To achieve the maximum sensitivity of the search strategy and to identify all studies, we combined “delayed ejaculation” as Medical Subject Headings (MeSH) terms or keywords with each of “testosterone” or “cabergoline” or “bupropion” or “amantadine” or “cyproheptadine” or “midodrine” or “imipramine” or “ephedrine” or “pseudoephedrine” or “yohimbine” or “buspirone” or “oxytocin” or “bethanechol” as MeSH terms or keywords. There are a number of drugs to treat patients with DE including: testosterone, cabergoline, bupropion, amantadine, cyproheptadine, midodrine, imipramine, ephedrine, pseudoephedrine, yohimbine, buspirone, oxytocin, and bethanechol. Although there are many pharmacological treatment options, the evidence is still limited to small trials, case series or case reports. Review of literature showed that evidence level 1 (Double blind randomized clinical trial) studies were performed with testosterone, oxytocin, buspirone or bethanechol treatment. It is concluded that successful drug treatment of DE is still in its infancy. The clinicians need to be aware of the pathogenesis of DE and the pharmacological basis underlying the use of different drugs to extend better care for these patients. Various drugs are available to address such problem, however their evidence of efficacy is still limited and their choice needs to be individualized to each specific case.

Behavioral effects of progesterone on pair bonding and partner preference in the female zebra finch (Taeniopygia guttata)

Progesterone is a sex steroid known to be involved in reproduction, but its role in pair relationships is not well understood. This study explored the effects of exogenous progesterone (P4) on courtship and pairing behaviors in female zebra finches (Taeniopygia guttata) in two separate experiments: the first focused on courtship and initial pair formation and the second examined the effects on pair maintenance. In these experiments, we tested the hypothesis that P4 increases pairing behaviors and consequently influences their partner preference. In Experiment 1, animals engaged in significantly more pairing behaviors when they were treated with P4 than when they received the vehicle. However, this effect was not partner-specific, since the association index (a marker for female partner preference) did not differ between treatment conditions. In Experiment 2, females were given two weeks to form a pair and then injected with P4 or vehicle. Pairs were observed that day and the subsequent day to determine if P4 caused a decrease in mate-directed behavior and an increase in extra pair behavior. P4 did not affect the quality of the pair relationship and did not increase extra pair behavior. These results suggest that P4 influences the overall quantity of initial pairing behaviors and may slightly increase the likelihood of partner preference formation over short time courses. However, P4 does not alter a previously established bond, suggesting there are likely separate mechanisms for initial pairing behaviors and pair maintenance.

Impact of androgen deprivation therapy on sexual function

Many patients with prostate cancer for whom androgen deprivation therapy (ADT) is indicated are young and desire to remain sexually active. In such patients, the side effects of androgen therapy on sexual function can be a source of serious reduction in overall quality of life. Providing the appropriate treatment options in this patient population is therefore essential. Nevertheless, treating such patients is challenging and an understanding of the underlying mechanisms of sexual physiology and pathophysiology is crucial to optimal patient care. In this paper, we reviewed what was known regarding the effects of ADT on sexual function in animal models and we also provided a detailed review on the effects of ADT on sexual health in humans and its treatment.

The protein synthesis inhibitor anisomycin reduces sex behavior during a critical period after testosterone treatment in male Syrian hamsters

Testosterone (T) is critical for maintaining male sexual behavior (MSB) in rodents, in part by altering protein synthesis in a well-defined neural circuit. The specific timing of protein synthesis essential for expression of MSB has never been investigated. We administered the protein synthesis inhibitor anisomycin (Ani) to castrated male Syrian hamsters treated sc with 100 μg T in an aqueous vehicle once weekly; this T regimen maintains MSB while elevating circulating T concentrations for only a few hours after each injection. Hamsters were injected s.c. with the vehicle or 12.5 mg Ani at one of several times relative to T administration; MSB was assessed once per week, 6 days after the previous T injection, for 5 weeks. Anisomycin administered 6-12 h after T injection significantly reduced the expression of sexual behavior, whereas Ani treatment between 3 h before and 3 h after T injection did not impair MSB. This experiment is the first to assess the specific timing of protein synthesis relative to a T pulse that is required for the expression of MSB. The demarcation of a critical interval for T-induced protein synthesis necessary for maintenance of MSB should facilitate specification of the genomic, proteomic, and biochemical cascades that subserve actions of T on male copulation.