Central mechanisms of erectile dysfunction: what a clinician may want to know

Is Internet Pornography Causing Sexual Dysfunctions? A Review with Clinical Reports

Traditional factors that once explained men's sexual difficulties appear insufficient to account for the sharp rise in erectile dysfunction, delayed ejaculation, decreased sexual satisfaction, and diminished libido during partnered sex in men under 40. This review (1) considers data from multiple domains, e.g., clinical, biological (addiction/urology), psychological (sexual conditioning), sociological; and (2) presents a series of clinical reports, all with the aim of proposing a possible direction for future research of this phenomenon. Alterations to the brain's motivational system are explored as a possible etiology underlying pornography-related sexual dysfunctions. This review also considers evidence that Internet pornography's unique properties (limitless novelty, potential for easy escalation to more extreme material, video format, etc.) may be potent enough to condition sexual arousal to aspects of Internet pornography use that do not readily transition to real-life partners, such that sex with desired partners may not register as meeting expectations and arousal declines. Clinical reports suggest that terminating Internet pornography use is sometimes sufficient to reverse negative effects, underscoring the need for extensive investigation using methodologies that have subjects remove the variable of Internet pornography use. In the interim, a simple diagnostic protocol for assessing patients with porn-induced sexual dysfunction is put forth.

The pharmacological properties and therapeutic use of apomorphine

Apomorphine (APO) is an aporphine derivative used in human and veterinary medicine. APO activates D₁, D_2S, D_2L, D₃, D₄, and D₅ receptors (and is thus classified as a non-selective dopamine agonist), serotonin receptors (5HT_1A, 5HT_2A, 5HT_2B, and 5HT_2C), and α-adrenergic receptors (α_1B, α_1D, α_2A, α_2B, and α_2C). In veterinary medicine, APO is used to induce vomiting in dogs, an important early treatment for some common orally ingested poisons (e.g., anti-freeze or insecticides). In human medicine, it has been used in a variety of treatments ranging from the treatment of addiction (i.e., to heroin, alcohol or cigarettes), for treatment of erectile dysfunction in males and hypoactive sexual desire disorder in females to the treatment of patients with Parkinson's disease (PD). Currently, APO is used in patients with advanced PD, for the treatment of persistent and disabling motor fluctuations which do not respond to levodopa or other dopamine agonists, either on its own or in combination with deep brain stimulation. Recently, a new and potentially important therapeutic role for APO in the treatment of Alzheimer’s disease has been suggested; APO seems to stimulate Aβ catabolism in an animal model and cell culture, thus reducing the rate of Aβ oligomerisation and consequent neural cell death.

The effect of amantadine on clomipramine induced sexual dysfunction in male rats

OBJECTIVE

Several studies have reported that Clomipramine has the ability to suppress male rat sexual behavior. Literature indicates that the activation of brain D(2) receptors causes facilitation of penile erection, and a number of reports have indicated dopamine's involvement in sexual function. Hence this study was undertaken to investigate the effect of Amantadine, a dopamine agonists on the Clomipramine induced sexual dysfunction.

METHODS

The study subjects involved a total of 48 males and 48 females, 4 months old Sprague-Dawley albino rats, all housed in a group of six males and females separately in plexi glass cages in an acclimatized colony room (25±0.5(0)C) maintained on a 12/12 hr light/dark cycle. The male rats were randomly divided into four groups of 12 male rats each. Group I served as controls. Group II, III, and IV were treated with Amantadine (9 mg/kg body weight, p.o) 30 min, prior to the treatment with 13.5 mg/kg, 27 mg/Kg and 54 mg/Kg bodyweight p.o of Clomipramine respectively for 60 days. The control group received vehicle 1 ml / kg p.o. The sexual behavior of the male rats was observed to determine the following parameters: mount latency, intromission latency, ejaculation latency, post ejaculatory pause, and intromission frequency. As well as the sexual behavior; serum testosterone and histopathology of the testes were also investigated in this study.

RESULTS

The results indicate that Amantadine in all aspects failed to antagonize Clomipramine induced sexual dysfunction in male rats. Even the sexual competence of male rats treated with ½ therapeutic dose (TD) of Clomipramine failed to regain their sexual competence in the presence of Amantadine. Testicular damage and decline in testosterone levels continued in the presence of Amantadine.

CONCLUSION

Overall, the results suggest that Amantadine could not be a safe antidote to antagonize Clomipramine induced sexual dysfunction.

Inhalation device allows novel administration of apomorphine in men with erectile dysfunction-efficacy and safety findings

INTRODUCTION

Erectile dysfunction (ED) treatment is greatly influenced by patient preference, and currently available oral therapies do not meet all patients' needs. New therapies and formulations are therefore being investigated.

AIM

The aim of this article is to assess the clinical efficacy and safety of inhaled apomorphine, VR004, in men with mild to severe ED.

MAIN OUTCOME MEASURES

Efficacy outcomes were the change in the proportion of positive responses to sexual encounter profile questions, International Index of Erectile Function (IIEF) scores and onset of therapeutic effect. Safety outcomes included a change in vital signs at an orthostatic challenge and adverse events (AEs).

METHODS

Two consecutive, multicenter trials each comprised a 4-week no-treatment period and a 12-week "at home" treatment period with regular clinic visits. Patients (N = 211 and N = 389) were randomized to receive one of three set doses of VR004 (100-300 microg) or matching placebo in each trial. VR004 was administered by a dry-powder inhaler at least once a week.

RESULTS

Efficacy was generally dose dependent. The proportion of per-protocol patients maintaining an erection long enough for successful intercourse increased in all VR004 groups vs. placebo. IIEF scores were higher in the VR004 groups compared with placebo, and the majority of responders achieved an erection within 10 minutes of dosing. The safety profile of VR004 was generally similar to that of placebo, and AEs were mild or moderate in severity. The incidence of treatment-related AEs was dose dependent. Few patients (4%) withdrew because of treatment-related AEs, and the majority of these withdrawals occurred on the day of the stringent orthostatic challenge.

CONCLUSIONS

The VR004 system administers low apomorphine doses that are well tolerated without compromising efficacy. This route of administration ensures a rapid onset of action and reproducible efficacy and safety profiles. Inhaled apomorphine is therefore a potential first-line treatment for ED.

A Double‐Blind Randomized Placebo Control Study Comparing the Objective and Subjective Changes in Female Sexual Response Using Sublingual Apomorphine

INTRODUCTION

Female sexual dysfunction and its therapeutic approach is a growing area.

AIM

We aimed to assess the subjective and objective changes of the female sexual response, in patients with orgasmic sexual dysfunction using 3 mg SL Apomorphine (APO).

METHODS

Twenty-four patients (mean age 32 years old, SD: 9.69) were included in a prospective randomized cross-over protocol. Sexual response was evaluated objectively (duplex ultrasound) and subjectively (self-reported questionnaire) following vibrator stimuli with the addition of 3 mg SL APO or placebo.

MAIN OUTCOME MEASURE

Sexual response objective (PSV, EDV, RI) and subjective (arousal and lubrication degree and orgasm achievement). Adverse events were also recorded.

RESULTS

Clitoral hemodynamical changes, particularly peak systolic velocity (PSV), were significantly higher with APO (P = 0.003), mean increase of PSV poststimulus was 72.50% with placebo (from 9.7 cm/second to 17.0 cm/second) and 139.14% with APO (from 9.7 cm/second to 21.4 cm/second). SUBJECTIVE CHANGES (AROUSAL AND LUBRICATION) WERE ALSO SIGNIFICATIVE WITH APO (P < 0.05).

CONCLUSION

According to our observations, APO seemed to produce more subjective and objective changes in the sexual arousal phase of women with orgasmic sexual dysfunction than placebo. Future research is needed to evaluate the place of this drug in the treatment of the female sexual dysfunction.