Does MDMA have treatment potential in sexual dysfunction? A systematic review of outcomes across the female and male sexual response cycles.

INTRODUCTION: Sexual health, an integral component of overall well-being, is frequently compromised by common yet underdiagnosed sexual dysfunctions. Traditional interventions encompass pharmaceutical and psychological treatments. Unconventional therapies, like MDMA, offer hope for sexual dysfunction. This review delves into MDMA's effects on sexual responsiveness and its potential role in treating sexual dysfunction. OBJECTIVES: The purpose of this review is to elucidate effects of MDMA on different domains of the female and male sexual response cycles. METHODS: We conducted a systematic review on the effects of MDMA on each domain of the female and male sexual response cycles. PubMed, MEDLINE, and EMBASE were queried, and results were screened using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Search terms utilized were "MDMA" or "ecstasy" in combination with "desire," "arousal," "lubrication," "orgasm," "pleasure," "libido," "erection," and "ejaculation." Inclusion criteria for this review were MDMA use by study subjects and sexual outcomes in at least 1 domain of the female and/or male sexual response cycles were described and measured. Randomized controlled trials, cohort studies (both prospective and retrospective), surveys, and literature reviews published between January 2000 and June 2022 were included. Case reports and studies that did not address conditions of interest were excluded from analysis. Duplicated search results were screened out. The remaining studies were then read in full text to ensure they met inclusion and exclusion criteria for analysis. RESULTS: We identified 181 studies, of which 6 met criteria for assessment of the female sexual response cycle and 8 met criteria for assessment of the male sexual response cycle. Four of 6 studies reported increased sexual desire with MDMA use among women. Arousal and lubrication were improved with MDMA use in 3 of 4 studies, but they were not affected in 1 randomized control study. In men, 7 studies evaluated the effects of MDMA on desire and/or arousal, 5 studies measured impact on erection, 3 on orgasm, and 2 on ejaculation. Sixty percent of interview-based studies reported increased sexual desire in men, while 40% reported mixed or no effect. Two studies reported impairment of erection, 2 reported mixed effects, and 1 reported fear of erection impairment. In both men and women, all studies evaluating orgasm reported delay in achieving orgasm but increased intensity and pleasure if achieved. Primary outcome measures were variable and largely qualitative. CONCLUSION: Our findings suggest that MDMA generally increases sexual desire and intensifies orgasm when achieved. While producing conflicting evidence on sexual arousal in both sexes, MDMA may impair erectile and ejaculatory function in men.

Dissociable effects of the prodrug phendimetrazine and its metabolite phenmetrazine at dopamine transporters.

Phendimetrazine (PDM) is a clinically available anorectic and a candidate pharmacotherapy for cocaine addiction. PDM has been hypothesized to function as a prodrug that requires metabolism to the amphetamine-like monoamine transporter substrate phenmetrazine (PM) to produce its pharmacological effects; however, whether PDM functions as an inactive prodrug or has pharmacological activity on its own remains unclear. The study aim was to determine PDM pharmacological mechanisms using electrophysiological, neurochemical, and behavioral procedures. PDM blocked the endogenous basal hDAT (human dopamine transporter) current in voltage-clamped (-60 mV) oocytes consistent with a DAT inhibitor profile, whereas its metabolite PM induced an inward hDAT current consistent with a DAT substrate profile. PDM also attenuated the PM-induced inward current during co-application, providing further evidence that PDM functions as a DAT inhibitor. PDM increased nucleus accumbens dopamine levels and facilitated electrical brain stimulation reinforcement within 10 min in rats, providing in vivo evidence supporting PDM pharmacological activity. These results demonstrate that PDM functions as a DAT inhibitor that may also interact with the pharmacological effects of its metabolite PM. Overall, these results suggest a novel mechanism for PDM therapeutic effects via initial PDM DAT inhibition followed by PM DAT substrate-induced dopamine release.

Abuse-Related Neurochemical Effects of Para-Substituted Methcathinone Analogs in Rats: Microdialysis Studies of Nucleus Accumbens Dopamine and Serotonin.

Methcathinone (MCAT) is a monoamine releaser and parent compound to a new class of designer drugs that includes the synthetic cathinones mephedrone and flephedrone. Using MCAT and a series of para-substituted (or 4-substituted) MCAT analogs, it has been previously shown that expression of abuse-related behavioral effects in rats correlates both with the volume of the para substituent and in vitro neurochemical selectivity to promote monoamine release via the dopamine (DA) versus serotonin (5-HT) transporters in rat brain synaptosomes. The present study used in vivo microdialysis to determine the relationship between these previous measures and the in vivo neurochemical selectivity of these compounds to alter nucleus accumbens (NAc) DA and 5-HT levels. Male Sprague-Dawley rats were implanted with bilateral guide cannulae targeting the NAc. MCAT and five para-substituted analogs (4-F, 4-Cl, 4-Br, 4-CH3, and 4-OCH3) produced dose- and time-dependent increases in NAc DA and/or 5-HT levels. Selectivity was determined as the dose required to increase peak 5-HT levels by 250% divided by the dose required to increase peak DA levels by 250%. This measure of in vivo neurochemical selectivity varied across compounds and correlated with 1) in vivo expression of abuse-related behavioral effects (r = 0.89, P = 0.02); 2) in vitro selectivity to promote monoamine release via DA and 5-HT transporters (r = 0.95, P < 0.01); and 3) molecular volume of the para substituent (r = -0.85, P = 0.03). These results support a relationship between these molecular, neurochemical, and behavioral measures and support a role for molecular structure as a determinant of abuse-related neurochemical and behavioral effects of MCAT analogs.

Epidermal growth factor-induced heparanase nucleolar localization augments DNA topoisomerase I activity in brain metastatic breast cancer.

Identification of molecular mechanisms responsible for brain metastatic breast cancer (BMBC) is imperative to develop novel therapies. However, current understanding of the molecular circuitry that governs BMBC dissemination remains fragmentary. Heparanase (HPSE) is the only functional mammalian endoglycosidase whose activity correlates with cancer metastasis, angiogenesis, and the reduced postoperative survival of cancer patients, making it an active target for anticancer therapeutics. We hypothesized that human epidermal growth factor receptor 2 (HER2)/epidermal growth factor receptor (EGFR) activation promotes HPSE function in human BMBC. To address this, we examined HPSE content, activity, and intracellular trafficking in a HER2/EGFR-expressing BMBC model system and show that HPSE is present, functional, and correlates with HER2 status. Further, we showed that EGF induced nucleolar translocation of HPSE in these cells in a dose- and time-dependent manner upon activation of HER2/EGFR. Knockdowns of HER2/EGFR by small interference RNA abolished EGF-induced HPSE nucleolar translocalization. It was also noted that nucleolar HPSE modulates DNA topoisomerase I (Topo I), an enzyme that is highly present in nucleoli, essential for DNA replication and transcription in a variety of tumors, and inhibited by heparan sulfate. Evidence is provided that HPSE can regulate Topo I activity, which subsequently affects BMBC cell proliferation. Finally, we showed that the nucleolar presence of HPSE with Topo I colocalization is detected only in HER2-overexpressing BMBC patient specimens. Altogether, these findings support the notion that HPSE is a critical downstream target of HER2 mechanisms driving BMBC and is potentially relevant for BMBC therapeutic interventions.