Differential effects of serotonin reuptake inhibitors on erectile responses, NO-production, and neuronal NO synthase expression in rat corpus cavernosum tissue

The comparison of efficacy of Escitalopram and Bupropion in treatment of depression symptoms in patients with heart failure: randomized clinical trial

Objective

This study aims to compare the effects of two medicines, Escitalopram and Bupropion, on HF patients who have depression symptoms.

Methods

This double-blind randomized clinical trial study was conducted on HF patients with depression symptoms at the Heart Failure Clinics affiliated with Babol University of Medical Sciences. In this study, 80 participants were examined for depression based on the Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HDRS). They were randomly allocated into two groups of 40 participants treated with Bupropion 75 mg and Escitalopram 5 mg. Following the intervention, the individuals were assessed in terms of their depression score at 4, 8, and 12-week intervals. Finally, the data were analyzed using SPSS version 22.0.

Results

In the examination of Beck and Hamilton scores in the two research groups during different follow-ups, a significant decrease was found over time (P<0.001 for both medicines). While the effectiveness of the two medicines was the same at different times (P>0.05 in all cases). Comparing the side effects between the two intervention groups, the orgasm disorder (P=0.018) and sexual dysfunction (P<0.001) were reported significantly more in the Escitalopram group than in the Bupropion group.

Conclusions

The findings of this study showed that Escitalopram has the same efficacy as Bupropion in the treatment of depression symptoms in HF patients.

Multistrain probiotic rescinds quinpirole-induced obsessive-compulsive disorder phenotypes by reshaping of microbiota gut-brain axis in rats

Obsessive-compulsive disorder (OCD) is a disabling mental condition that poses recurring bothersome intrusive thoughts, obsessions, and compulsions. Considering the positive impact of probiotics on neuropsychiatric disorders, herein, we investigated the effect of multistrain probiotic (Bifidobacterium lactis UBBLa-70, Bacillus coagulans Unique IS-2, Lactobacillus rhamnosus UBLR-58, Lactobacillus plantarum UBLP-40, Bifidobacterium infantis UBBI-01, Bifidobacterium breve UBBr-01, and glutamine) in the management of OCD-like phenotype in rats. Rats injected with quinpirole for 5 weeks showed an increased number of marble burying and self-grooming episodes. Quinpirole-injected animals also did less head dipping in the hole board test and avoided exploration of open spaces in the elevated-plus maze. These repetitive, compulsive, self-directed, and anxiety-like phenotypes were abolished after 8-week of multistrain probiotic treatment. The probiotic formulation also prevented the elevated mRNA expression of interleukin-6, tumor-necrosis factor-α, and C-reactive protein in the amygdala and dysregulated levels of 5-hydroxytryptamine, dopamine, and noradrenaline in the frontal cortex of quinpirole-injected rats. The level of brain-derived neurotrophic factor in the frontal cortex remained unaffected across the groups. The altered levels of goblet cells and crypt-to-villi ratio in quinpirole rats were prevented by multistrain probiotic treatment. The results of 16S-rRNA gene-sequencing of gut microbiota from feces contents revealed an elevation in the abundance of Allobaculum and Bifidobacterium species (specifically Bifidobacterium animalis), while the presence of Lactobacillus species (including Lactobacillus reuteri and Lactobacillus vaginalis) exhibited a decline in quinpirole-induced rats. These results imply that modifying the gut-brain axis may be a possible mechanism by which selective multistrain probiotic therapy prevents OCD-like behaviors.

The association of hypogonadism with depression and its treatments

According to World Health Organization estimates, 5% of the adult population worldwide suffers from depression. In addition to the affective, psychomotor and cognitive symptoms which characterize this mood disorder, sexual dysfunction has been frequently reported among men suffering from depression. The most common sexual manifestations are decreased libido, erectile dysfunction and orgasmic disorder. In addition, epidemiological studies have documented a reduction of testosterone concentrations in men with depression and, for these reasons, depressive disorders appear as one possible cause of male functional hypogonadism. Moreover, some largely used antidepressant medications can cause or worsen sexual complaints, thus depression and its treatments rise several andrological-relevant issues. The other way round, men with hypogonadism can manifest depressed mood, anxiety, insomnia, memory impairment which, if mild, may respond to testosterone replacement therapy (TRT). However, the prevalence of functional hypogonadism in depression, and of depressive symptoms in hypogonadal men, is not known. Severe depressive symptoms do not respond to TRT, while the effect of treating major depression on functional hypogonadism, has not been investigated. Overall, the clinical relevance of each condition to the other, as well as the physiopathological underpinnings of their relationship, are still to be clarified. The present review summarizes current evidence on the influence of testosterone on mood and of depression on the hypothalamic-pituitary-testis axis; the clinical association between male hypogonadism and depression; and the reciprocal effects of respective treatments.

The pathophysiology of Post SSRI Sexual Dysfunction - Lessons from a case study

BACKGROUND

Although Post-SSRI Sexual Dysfunction (PSSD) has finally been recognized by the European Medicines Agency as a medical condition that can outlast discontinuation of SSRI and SNRI antidepressants, this condition is still largely unknown by patients, doctors, and researchers, and hence, poorly understood, underdiagnosed, and undertreated.

OBJECTIVE

Becoming familiar with the symptomatology of PSSD and understanding the underlying mechanisms and treatment options.

METHOD

We applied a design thinking approach to innovation to 1) provide insights into the medical condition as well as the personal needs and pains of a targeted patient; and 2) generate ideas for new solutions from the perspective of this particular patient. These insights and ideas informed a literature search on the potential pathophysiological mechanisms that could underlie the patient's symptoms.

RESULTS

The 55-year-old male patient developed symptoms of low libido, delayed ejaculation, erectile dysfunction, 'brain zaps', overactive bladder and urinary inconsistency after discontinuation of the SNRI venlafaxine. In many of these symptoms a dysregulation in serotonergic activity has been implicated, with an important role of 5-HT_1A receptor downregulation and possible downstream effects on neurosteroid and oxytocin systems.

CONCLUSIONS

The clinical presentation and development of symptoms are suggestive of PSSD but need further clinical elaboration. Further knowledge of post-treatment changes in serotonergic - and possibly noradrenergic - mechanisms is required to improve our understanding of the clinical complaints and to inform appropriate treatment regimes.

A review of experimental techniques for erectile function researches and development of medical technology using animal erectile dysfunction models in sexual and reproductive medicine

Background

Erectile dysfunction (ED) is one of the causes of male infertility and is a disease that requires treatment. The first-line drugs for ED are phosphodiesterase 5 (PDE-5) inhibitors, and further treatment options are currently limited. Medical technologies, such as genetic control and regenerative medicine, are developing rapidly. Research on erectile function is progressing rapidly, coupled with technological innovations in other areas.

Methods

A PubMed search using the keywords "animal (rat, mouse, rabbit, dog, and monkey)" and "erectile" was conducted, and all relevant peer-reviewed English results were evaluated.

Main findings

The methods for evaluating erectile function include intracavernous pressure (ICP) measurements, isometric tension studies, and dynamic infusion cavernosometry. Papers also reported various disease model animals for the study of diabetes mellitus, cavernous nerve injury, and drug-induced ED.

Conclusion

Basic research on ED treatment has progressed rapidly over the past 20 years. In particular, research on the mechanism of ED has been accelerated by the publication of a study on the evaluation of erectile function using ICP measurements in rats. In addition, molecular biological experimental methods such as polymerase chain reaction (PCR) and western blotting have become relatively easy to perform due to technological progress, thus advancing research development.

Plantain peels restore sexual performance, hormonal imbalance, and modulate nitric oxide production and key enzymes of penile function in paroxetine-sexually impaired male rats

This study focused on the effect of unripe (UPP) and ripe (RPP) plantain peels' extracts (200 and 400 mg/kg) on sexual behavior, hormonal profiles [testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH)], and enzymes [acetylcholinesterase (AChE), phosphodiesterase-5' (PDE-5), arginase, angiotensin-I converting enzyme (ACE), ecto-5'neucleotidase, and adenosine deaminase (ADA)] in paroxetine (PAR)-induced penile dysfunction rats. From the result, arginase, PDE-5', ACE, ecto-5'-nucleotidase ADA, and AChE activities, sexual activities, hormonal profile, and NO level were reduced, while thiobarbituric acid reactive species (TBARS) level increased (p < .05) relative to normal control rats. However, treatment with UPP and URP reduced the activities of these enzymes, decreased TBARS levels, and increased hormones, and penile NO levels in PAR-induced rats. Thus, the use of UPP and RPP could be channeled towards the improvement of sexual performance in erectile dysfunction (ED) disorder. PRACTICAL APPLICATIONS: Plantain fruits are a tropical staple food crop commonly consumed at various stages of ripeness and cooking methods. However, its peels are regarded as a waste product with reported cases of environmental menace. Interestingly, plantain peel is being used as a major raw material for industrial applications in the agro-based industries and in folklore for the treatment of many human ailments due to its rich phytochemicals such as polyphenols, carotenoids, alkaloids, etc., which have been reported. A prelude study has also indicated its usefulness in ED management, but further pharmacological investigations are needed to proffer information on its effect in ED management and its anti-androgenic activity in male Wistar rats. The information from this study could be of pharmaceutical importance in designing natural remedies capable of improving penile rigidity, hormone profiles, and alteration of enzymes linked with ED.

Narrative review: pathogenesis, diagnosis, and treatment of sleep-related painful erection

Objective

Through critical analysis and comprehensive review of the limited literature, this paper can help clinicians better identify the pathophysiology of sleep-related painful erections (SRPE) and provide direction for future treatment research.

Background

Patients with SRPE will be awakened by painful erections during sleep, which affects their sleep process and general health. At present, literatures of experimental and clinical research on SRPE disease are limited, as well as long-term reports on its pathogenesis and clinical management.

Methods

We use the PubMed database to obtain sleep-related peer erection literature. The search terms used include sleep, painful, penis and erection. After rigorous screening, the search returned 21 references published between 1987 and 2021.

Conclusions

The main cause of SRPE is obstructive sleep apnea (OSA) syndrome, psychological and spiritual factors, androgen elevation, neuroendocrine regulation and threshold of pain in the REM phase. The combination of multiple medications is the most effective approach to treat sleep-pain-related erections. The combination of CPAP, REM inhibitors and Baclofen has significant effect on SRPE caused by OSA syndrome. This article provides effective support and strategies for doctors to manage SRPE patients through a comprehensive analysis of the pathogenesis mechanism and clinical treatment strategies of SRPE.

Ketamine alleviating depressive-like behaviors is associated with regulation of nNOS-CAPON-Dexras1 complex in chronic unpredictable mild stress rats

BACKGROUND

A growing number of studies have demonstrated that ketamine induces rapid and sustained antidepressant action. Neuronal nitric oxide synthase (nNOS) signaling has been explored for the treatment of neuropsychiatric disorders for decades. But the effect of ketamine on nNOS signaling is poorly understood. The aim of the present study was to investigate the effect of ketamine on nNOS signaling in a chronic unpredictable mild stress (CUMS) model of depression.

METHODS

Forty-eight rats were randomly divided into four groups: the control group of healthy rats (group C), the healthy rats treated with ketamine 10 mg/kg for 3 days (group CK), the rats model of stress-induced depression group (group D), and the depressed group treated with ketamine 10 mg/kg for 3 days (group DK). The sucrose preference test and open field test were used to assess behavioral changes. Immunohistochemistry, immunofluorescence, and real-time PCR analysis were carried out to measure the expression of nNOS, CAPON, and Dexras1 in the prefrontal cortex (PFC) of the CUMS rats.

RESULTS

Compared with healthy rats, the total distance traveled, the rearing counts, the sucrose preference percentage (SPP), and CAPON and Dexras1 expression in the PFC significantly decreased, while nNOS expression increased in CUMS rats. After treating with ketamine, the total distance traveled, the rearing counts, the SPP, and CAPON and Dexras1 expression significantly increased, while nNOS expression significantly decreased.

CONCLUSION

The results indicated that ketamine improved the depressive behavior of rats, which may be related to the reduced nNOS expression and enhanced CAPON and Dexras1 expression.

Post-SSRI Sexual Dysfunction (PSSD): Biological Plausibility, Symptoms, Diagnosis, and Presumed Risk Factors

INTRODUCTION

Post-SSRI sexual-dysfunction (PSSD) is an iatrogenicsyndrome, the underlying neurobiological mechanisms of which areunclear. Symptom onset follows cessation of serotonergicantidepressants i.e. Selective Serotonin and Norepinephrine ReuptakeInhibitors (SSRI's, SNRI's), and Tricyclic antidepressants (TCA's). PSSDsymptoms include genital anesthesia, erectile dysfunction andorgasmic/ejaculatory anhedonia, and should be differentiated fromdepression-related sexual-dysfunction. Recently, accumulated data of numerous case-reports suggest additional non-sexual symptoms including, anhedonia, apathy, and blunted affect. PSSD gained official recognition after the European medical agency concluded that PSSD is a medical condition that persists after discontinuation of SSRI's and SNRI's.

OBJECTIVE

To review possible underlying neurobiological mechanisms ofthis syndrome, update information on the pathophysiology, present a listof potential risk-factors and discuss potential management options forPSSD.

METHODS

Extensive literature review on the main symptom-patterns ofthis disorder was undertaken using PubMed. It includes introductoryexplications of relevant neurobiology with the objective of generatinghypothesis.

RESULTS

Precipitating factors for PSSD include previous exposure to certain drugs, genetic predisposition, psychological stress or chemical stressful reaction to antidepressants along pre-existing medical conditions affecting neuroplasticity. Different theories have been proposed to explain the pathophysiology of PSSD: epigenetic gene expression, dopamine-serotonin interactions, serotonin neurotoxicity and hormonal changes. The diagnosis of PSSD is by excluding all other etiologies of sexual-dysfunction. Treatment is challenging, and many strategies have been suggested without definitive outcomes. We offerthe contours of a future neurobiological research agenda, and propose several underlying mechanisms for the various symptoms of PSSD which could be the foundation for a future treatment algorithm.

CONCLUSION

There is a need for well-designed neurobiological research in this domain, as well as in the prevalence, pathophysiology, and treatment of PSSD. Practitioners should be alert to the distinctive features of PSSD. Misdiagnosing this syndrome might lead to harmful Sexual Medicine Reviews. Peleg LC, Rabinovitch D, Lavie Y, et al. Post-SSRI Sexual Dysfunction (PSSD): Biological Plausibility, Symptoms, Diagnosis, and Presumed Risk Factors. Sex Med Rev 2021;XX:XXX-XXX.

Effects of paroxetine treatment and its withdrawal on neurosteroidogenesis

Selective serotonin reuptake inhibitors (SSRI) show high efficacy in treating depression, however during treatment side effects, like for instance sexual dysfunction, may appear, decreasing compliance. In some cases, this condition will last after drug discontinuation, leading to the so-called post-SSRI sexual dysfunction (PSSD). The etiology of PSSD is still unknown, however a role for neuroactive steroids may be hypothesized. Indeed, these molecules are key physiological regulators of the nervous system, and their alteration has been associated with several neuropathological conditions, including depression. Additionally, neuroactive steroids are also involved in the control of sexual function. Interestingly, sexual dysfunction induced by SSRI treatment has been also observed in animal models. On this basis, we have here evaluated whether a subchronic treatment with paroxetine for two weeks and/or its withdrawal (i.e., a month) may affect the levels of neuroactive steroids in brain areas (i.e., hippocampus, hypothalamus, and cerebral cortex) and/or in plasma and cerebrospinal fluid of male rats. Data obtained indicate that the SSRI treatment alters neuroactive steroid levels and the expression of key enzymes of the steroidogenesis in a brain tissue- and time-dependent manner. Indeed, these observations with the finding that plasma levels of neuroactive steroids are not affected suggest that the effect of paroxetine treatment is directly on neurosteroidogenesis. In particular, a negative impact on the expression of steroidogenic enzymes was observed at the withdrawal. Therefore, it is possible to hypothesize that altered neurosteroidogenesis may also occur in PSSD and consequently it may represent a possible pharmacological target for this disorder.

Erectile and Ejaculatory Dysfunction Associated with Use of Psychotropic Drugs: A Systematic Review

BACKGROUND

Sexual dysfunction may be a side effect of treatment with antipsychotics, antidepressants, and other psychotropic drugs.

AIM

To review the evidence concerning male sexual dysfunctions in patients taking psychotropic drugs to provide specific information to nonpsychiatric physicians for the management of these dysfunctions.

METHODS

A systematic search of Medline and Embase databases was performed up to October 15th, 2020. We included randomized controlled trials comparing the effects of psychotropic drugs versus placebo or versus another drug of the same class, for at least 5 weeks.

OUTCOMES

We considered studies whose male population could be evaluated separately from the female population and with a separate analysis of the different phases of the male sex cycle.

RESULTS

We included 41 studies in the final review. There was a significant association between sexual dysfunction and antidepressant drug therapy, compared to placebo (decreased libido OR 1.89, 95% CI:1.40 to 2.56, 22 series, 11 trials, 7706 participants; erectile dysfunction OR = 2.28, 95% CI: 1.31 to 3.97; 11 trials, 3008 participants; ejaculatory dysfunction OR = 7.31, 95% CI: 4.38 to 12.20,19 trials, 3973 participants). When the effects of selective serotonin reuptake inhibitors (SSRIs) were evaluated separately from those of serotonin/norepinephrine reuptake inhibitors (SNRIs), the use of SNRIs but not that of SSRIs was characterized by significantly higher odds of erectile dysfunction compared to placebo. Only limited data were found regarding the effects of antipsychotics on the phases of the male sexual cycle, as it was shown that aripiprazole and risperidone showed lower and higher odds for erectile or ejaculatory dysfunction, respectively, compared to other atypical antipsychotics.

CLINICAL IMPLICATIONS

Treatment of male sexual dysfunction in patients taking psychotropics requires a basic knowledge of the different drugs that affect sexual function with different mechanisms.

STRENGTHS & LIMITATIONS

The effects of psychotropic drugs on erectile function and ejaculation were evaluated separately. The great variability of the mechanisms of action makes it difficult to make comparisons between the effects of the different classes of psychotropic drugs.

CONCLUSIONS

Administration of antipsychotics affects male sexual function with different mechanisms, although the increase in prolactin values associated with the administration of first-generation antipsychotics and some atypical, such as risperidone, seems to play a primary role in determining male sexual dysfunction. Most antidepressants cause decreased libido, ejaculatory and erectile dysfunction, however the administration of SNRIs appears to be possibly associated with a specific risk of erectile dysfunction. Trinchieri M, Trinchieri M, Perletti G, et al. Erectile and Ejaculatory Dysfunction Associated with Use of Psychotropic Drugs: A Systematic Review. J Sex Med 2021;18:1354-1363.

Latent Sex Differences in CaMKII-nNOS Signaling That Underlie Antidepressant-Like Effects of Yueju-Ganmaidazao Decoction in the Hippocampus

Previous studies have demonstrated that Yueju-Ganmaidazao (YG) decoction induces rapid antidepressant-like effects, and the antidepressant response is mostly dependent on the suppression of nitric oxide-cyclic guanosine monophosphate signaling in male mice. This study aimed to investigate the sex difference mediated by calcium/calmodulin-dependent protein kinase II (CaMKII)-neuronal nitric oxide synthase (nNOS) signaling involved in the antidepressant-like effect of YG in mice. We found that the immobility times in the tail suspension test (TST) were found to be decreased after the single injection of YG in male and female mice with the same dosage. Additionally, chronic administration for 4 days of subthreshold dosage of YG and escitalopram (ES) also significantly decreased the immobility time in mice of both sexes. Chronic subthreshold dosage of YG and ES in LPS-treated mice and in chronic unpredictable stress (CUS) mice both decreased the immobility time, which was increased by stress. Meanwhile, in CUS-treated mice, sucrose preference test, forced swimming test, and open field test were applied to further confirm the antidepressant-like effects of YG and ES. Moreover, CUS significantly decreased the expression of nNOS and CaMKII, and both YG and ES could enhance the expression in the hippocampus of female mice, which was opposite to that in male mice, while endothelial nitric oxide synthase expression was not affected by stress or drug treatment neither in male mice nor in female mice. Finally, subthreshold dosage of YG combined with 7-nitroindazole (nNOS inhibitor) induced the antidepressant-like effects both in female and in male mice, while the single use of YG or 7-NI did not display any effect. However, pretreatment with KN-93 (CaMKII inhibitor) only blocked the antidepressant-like effect of high-dosage YG in female mice. Meanwhile, in CUS mice, chronic stress caused NR1 overexpression and inhibited cAMP response element binding protein action, which were both reversed by YG and ES in male and female mice, implying that YG and ES produced the same antidepressant-like effect in mice of both sexes. The study revealed that chronic treatment with a subthreshold dose of YG also produced antidepressant-like effects in female mice, and these effects depended on the regulation of the CaMKII-nNOS signaling pathway.

Bioactive Flavonoid Glycosides and HPLC and UPLC Quantification of Commercial Astragali Complanati Semen

Eleven compounds, including nine known flavonoid glycosides (1-4, 6-8, and 10-11), one isoflavone glycoside (5), and a glansreginic acid (9), were isolated from the 80% ethanol extract of commercial Astragali Complanati Semen (ACS). All chemical structures were determined by spectroscopic analyses, including 1D and 2D NMR. Compounds 2, 4, 5, 6, 9, and 10 were isolated and identified from the title plant for the first time. Biological evaluation revealed that all the isolates showed promising anti-NO production, and 1, 2, 3, and 8 were more potent in antioxidant activity than vitamin E. The major peaks in the UPLC and HPLC profiles identified their chemical structures by comparing their retention time and UV spectra with those of the reference substances. Furthermore, nine of the eleven samples collected from North, Middle, and South regions of Taiwan possessed similar HPLC fingerprints and were identified as Astragali Complanati Semen, whereas the other two samples from southern Taiwan would be the adulterants due to the different fingerprinting patterns. In addition, an HPLC-UV method was employed to determine the content of target compound complanatuside (11) with good linear regression (R2 = 0.9998) for ACS in the Taiwanese market. Of the isolates, flavonol glycosides 1 and 3 were the major peaks in HPLC/UPLC, and showed more potent antioxidant and anti-NO production activities than that of 11, revealing that these compounds can be the available agents for the quality control of ACS.

European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction

INTRODUCTION

Rodent animal models are currently the most used in vivo model in translational studies looking into the pathophysiology of erectile dysfunction after nerve-sparing radical prostatectomy.

AIM

This European Society for Sexual Medicine (ESSM) statement aims to guide scientists toward utilization of the rodent model in an appropriate, timely, and proficient fashion.

METHODS

MEDLINE and EMBASE databases were searched for basic science studies, using a rodent animal model, looking into the consequence of pelvic nerve injury on erectile function.

MAIN OUTCOME MEASURES

The authors present a consensus on how to best perform experiments with this rodent model, the details of the technique, and highlight possible pitfalls.

RESULTS

Owing to the specific issue-basic science-Oxford 2011 Levels of Evidence criteria cannot be applied. However, ESSM statements on this topic will be provided in which we summarize the ESSM position on various aspects of the model such as the use of the Animal Research Reporting In Vivo Experiments guideline and the of common range parameter for nerve stimulation. We also highlighted the translational limits of the model.

CONCLUSION

The following statements were formulated as a suggestive guidance for scientists using the cavernous nerve injury model. With this, we hope to standardize and further improve the quality of research in this field. It must be noted that this model has its limitations. Weyne E, Ilg MM, Cakir OO, et al. European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction. Sex Med 2020;8:327-337.

Prevalence of antidepressant-induced sexual dysfunction among psychiatric outpatients attending a tertiary care hospital

Objectives:

To measure the prevalence of sexual dysfunction in psychiatric outpatients treated with fluoxetine, paroxetine, venlafaxine or mirtazapine.

Methods:

This is a retrospective cross-sectional study conducted in Sultan Qaboos University Hospital, Muscat, Oman. All patients above 18 years of age, attending psychiatric clinic and taking fluoxetine, paroxetiene, venlafaxine or mirtazapine for various indications were invited to participate in the study. A data collection sheet was designed to document the patients’ demographic features, psychiatric diagnosis, type, dose and duration of antidepressant treatment. Sexual side effects’ part of Toronto Side Effect Scale (TSES) was used to assess the presence of sexual dysfunction.

Results:

A total of 137 patients (Male: 51%, Female: 49%) were included in the study. The mean age for the participants was 38 years (range: 19-72 years). The number of patients for each antidepressant was as follows: paroxetine (52 patients), fluoxetine (36), mirtazapine (36 patients) and venlafaxine (17 patients). The average duration of the antidepressant use was 3.9 years. The overall prevalence of sexual dysfunction was 39%. Paroxetine was the most common antidepressant associated with sexual dysfunction especially for decreased libido (59.6%) and delayed ejaculation (34.4%). In contrary, mirtazapine was the lowest among antidepressants to cause sexual dysfunction.

Conclusion:

Sexual dysfunction is common among patients treated with antidepressants particularly selective serotonin reuptake inhibitors (SSRIs). Addressing this side effects early in treatment can improve compliance to treatment and prevent relapse.

Nitric oxide: Antidepressant mechanisms and inflammation

Millions of individuals worldwide suffers from mood disorders, especially major depressive disorder (MDD), which has a high rate of disease burden in society. Although targeting the biogenic amines including serotonin, and norepinephrine have provided invaluable links with the pharmacological treatment of MDD over the last four decades, a growing body of evidence suggest that other biologic systems could contribute to the pathophysiology and treatment of MDD. In this chapter, we highlight the potential role of nitric oxide (NO) signaling in the pathophysiology and thereby treatment of MDD. This has been investigated over the last four decades by showing that (i) levels of NO are altered in patients with major depression; (ii) modulators of NO signaling exert antidepressant effects in patients with MDD or in the animal studies; (iii) NO signaling could be targeted by a variety of antidepressants in animal models of depression; and (iv) NO signaling can potentially modulate the inflammatory pathways that underlie the pathophysiology of MDD. These findings, which hypothesize an NO involvement in MDD, can provide a new insight into novel therapeutic approaches for patients with MDD in the future.

Tadalafil Preserves Penile Nitric Oxide Synthase from Detrimental Effect of Paroxetine in Rats

OBJECTIVE

Paroxetine is a commonly prescribed SSRI that can impair erectile function in animal models via inhibition of nitric oxide synthase (NOS). Tadalafil potentiates nitric oxide (NO)-mediated responses in isolated trabecular smooth muscle and penile erection. The purpose of this study was to evaluate the impact of co-administering tadalafil with paroxetine on penile NOS levels in rats.

MATERIALS AND METHODS

A total of 30 male Sprague-Dawley rats were divided into 3 groups as control (Group-C), paroxetine (Group-P) and paroxetine plus tadalafil (Group-P+T). After 28 days of treatment, rats were sacrificed and their penile tissues were harvested for analysis. NOS isoform protein levels and immunoreactivity scores of NOS were assessed. Statistical significance level was set at p<0.05.

RESULTS

Neuronal NOS (nNOS) levels were significantly decreased in group-P, compared with group-C (p<0.001). In comparison, rats in group-P+T had significantly higher nNOS levels compared to group-P (p<0.001). Endothelial NOS (eNOS) and inducible NOS (iNOS) levels were significantly higher in group-P compared with group-C (p<0.01). The levels of eNOS and iNOS in group-P+T were similar to group-C.

CONCLUSION

Daily treatment with tadalafil prevented chronic paroxetine-induced changes in all three NOS isoform levels. Tadalafil treatment may therefore be a useful therapy in men with paroxetine-associated erectile dysfunction.

The Relaxant Mechanisms of Hydrogen Sulfide in Corpus Cavernosum

In several animal and human studies, the contribution of the endothelium, nitric oxide/soluble guanosine monophosphate (NO/cGMP) pathway, adenylyl cyclase, phosphodiesterase (PDE), potassium (K⁺) channels, L-type calcium channels, Na⁺-K⁺-ATPase, muscarinic acetylcholine receptors, RhoA/Rho-kinase pathway, and cyclooxygenase (COX)/arachidonic acid cascade on the relaxant mechanism of L-cysteine/H₂S pathway in corpus cavernosum has been investigated. In this chapter the relaxant mechanisms of H₂S in corpus cavernosum is discussed with data available in the current relevant literature. Also, in vitro experimental procedure for mice corpus cavernosum which used to investigate the relaxant effect of H₂S is given in detail.

Parquetina nigrescens leaves: chemical profile and influence on the physical and biochemical indices of sexual activity of male Wistar rats

OBJECTIVE

The leaves of Parquetina nigrescens have been claimed in folk medicine to be useful for managing sexual dysfunction, but there is inadequate scientific evidence for this claim. This investigation was conducted to assess the effects of aqueous leaf extract of Parquetina nigrescens (AEPN) in rats induced with sexual dysfunction.

METHODS

Male rats were allocated into various groups after being induced into sexual dysfunction with paroxetine hydrochloride. The groups were treated with distilled water, PowMaxM (reference drug), and the AEPN at 20, 40 and 80 mg/kg body weight (BW) respectively for 7 d. Frequencies of mount (MF), intromission (IF), ejaculation (EF), as well as latencies of mount (ML), intromission (IL) and post-ejaculatory interval (PEI) were progressively monitored with receptive female rats on days 1, 3 and 7. The precentage of mounted, intromitted, and ejaculated rats, intromission ratio (IR), copulatory efficiency (CE) and intercopulatory interval (ICI) were also computed. Standard methods were employed to determine the levels of serum luteinizing and follicle stimulating hormones (LH and FSH), testosterone, nitric oxide (NO) and the activity of phosphodiesterase V (PDE5).

RESULTS

The plant contained alkaloids, saponins, flavonoids, cardiac glycosides, steroids, tannins, phlobatannins, cardenolides, phenolics, anthraquinones and triterpenes with alkaloids (2.32 mg/g) occurring in greatest quantity while flavonoids, anthraquinones and cardenolides (0.01 mg/g, each) were the least. All the 20 standard amino acids were detected in the plant leaf, with the lowest concentration being 0.30 mg/g for methionine and the highest being 2.12 mg/g for cysteine. Furthermore, P. nigrescens leaves contained Na, K, Fe, Mg, Zn, Ca, Cu, Mn, P, Pb, Cd, Ni, Cr, and Co, with Fe present in the highest and Co the lowest concentrations. Paroxetine significantly (P<0.05) reduced MF, IF, EF, percentage mounted , intromitted, ejaculated, IR, CE, serum testosterone, LH, FSH and NO, while ML, IL, PEI, IF and PDE5 were significantly (P<0.05) increased and/or prolonged. The AEPN significantly reversed these paroxetine-treatment-related alterations with most profound activity at the highest dose of 80 mg/kg BW, similar to that of the PowMaxM-treated animals.

CONCLUSION

The AEPN restored both the physical and biochemical indices of male sexual activity/competence via changes in reproductive hormones, NO and PDE5 activity. The pro-sexual activity, attributed to a myriad of mineral, amino acid and secondary metabolite constituents, was best at 80 mg/kg BW of AEPN.

Different Endocrine Effects of an Evening Dose of Amitriptyline, Escitalopram, and Placebo in Healthy Participants

Objective

The primary aim of this study was to further characterize the acute effects of amitriptyline (AMI) and escitalopram (ESC) on serum levels of ghrelin, leptin, cortisol and prolactin in healthy humans.

Methods

Eleven healthy male participants received a single dose of AMI 75 mg, ESC 10 mg, or placebo (PLA) at 9:00 PM in a double blind, randomized, controlled, repeated measures study separated by one week. Fasting morning serum levels (7:00 AM) of ghrelin, leptin, cortisol and prolactin were assessed.

Results

A repeated measures multivariate analysis of variance revealed a significant main effect for the factor condition (AMI, ESC, PLA). Subsequent univariate analyses demonstrated significant condition effects for ghrelin and cortisol. Post-hoc analyses demonstrated a significant reduction of ghrelin levels after AMI in comparison to PLA, and a significant reduction of cortisol levels after AMI in comparison to both ESC and PLA. Other contrasts did not reach statistical significance.

Conclusion

Administration of a single dose of AMI, but not of ESC, leads to a significant reduction in morning serum ghrelin and cortisol levels. No effects on leptin and prolactin levels were observed. The differential impact of AMI and ESC on hormones might contribute to different adverse effect profiles of both substances.

Pathologic role of nitrergic neurotransmission in mood disorders

Mood disorders are chronic, recurrent mental diseases that affect millions of individuals worldwide. Although over the past 40 years the biogenic amine models have provided meaningful links with the clinical phenomena of, and the pharmacological treatments currently employed in, mood disorders, there is still a need to examine the contribution of other systems to the neurobiology and treatment of mood disorders. This article reviews the current literature describing the potential role of nitric oxide (NO) signaling in the pathophysiology and thereby the treatment of mood disorders. The hypothesis has arisen from several observations including (i) altered NO levels in patients with mood disorders; (ii) antidepressant effects of NO signaling blockers in both clinical and pre-clinical studies; (iii) interaction between conventional antidepressants/mood stabilizers and NO signaling modulators in several biochemical and behavioral studies; (iv) biochemical and physiological evidence of interaction between monoaminergic (serotonin, noradrenaline, and dopamine) system and NO signaling; (v) interaction between neurotrophic factors and NO signaling in mood regulation and neuroprotection; and finally (vi) a crucial role for NO signaling in the inflammatory processes involved in pathophysiology of mood disorders. These accumulating lines of evidence have provided a new insight into novel approaches for the treatment of mood disorders.

Involvement of nitric oxide in anticompulsive-like effect of agmatine on marble-burying behaviour in mice

In view of the reports that nitric oxide modulates the neurotransmitters implicated in obsessive-compulsive disorder (OCD), patients with OCD exhibit higher plasma nitrate levels, and drugs useful in OCD influence nitric oxide. Agmatine is a polyamine and widely distributed in mammalian brain which interacts with nitrergic systems. Hence, the present study was carried out to understand the involvement of nitrergic systems in the anticompulsive-like effect of agmatine. We used marble-burying behaviour (MBB) of mice as the animal model of OCD, and nitric oxide levels in hippocampus (HC) and cortex homogenate were measured. Results revealed that, agmatine (20 and 40mg/kg, i.p) significantly inhibited the MBB. Intraperitoneal administration of nitric oxide enhancers viz. nitric oxide precursor - l-arginine (l-ARG) (400mg/kg and 800mg/kg) increased MBB as well as brain nitrites levels, whereas treatment with N(G)-nitro-l-arginine methyl ester (l-NAME) neuronal nitric oxide synthase inhibitor (30mg/kg and 50mg/kg, i.p.) and 7-nitroindazole (7-NI) (20mg/kg and 40mg/kg) attenuated MBB and nitrites levels in brain. Further, in combination studies, the anticompulsive-like effect of agmatine (20mg/kg, ip) was exacerbated by prior administration of l-ARG (400mg/kg) and conversely l-NAME (15mg/kg) or 7-NI (10.0mg/kg) attenuated OCD-like behaviour with HC and cortex changes in the levels of NO. None of the above treatment had any significant influence on locomotor activity. In conclusion, Agmatine is effective in ameliorating the compulsive-like behaviour in mice which appears to be related to nitric oxide in brain.

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

Psychotropic-induced sexual dysfunction

Psychotropic-induced sexual dysfunction is a common and bothersome side effect of psychotropic medications. The majority of information available on the subject primarily pertains to antidepressants, but antipsychotics can also cause significant sexual dysfunction. The mechanisms behind these adverse events are thought to be primarily due to antidepressants' effects on serotonin and to antipsychotics' anti-dopaminergic activity. Sexual dysfunction can have many causes, not just psychotropic medication, therefore this article aims to examine the etiology of sexual dysfunction, as well as discuss differential diagnoses. Treatment for psychotropic-induced sexual dysfunction will be discussed, with more data available for the treatment of antidepressant-induced sexual dysfunction. The paucity of data for antipsychotic-induced sexual dysfunction does make it more difficult to treat.

Hippocampus and nitric oxide

Since it was first identified to play an important role in relaxation of blood vessels, nitric oxide has been demonstrated to regulate many biological processes, especially in the central nervous system. Of the three types of enzymes that produce nitric oxide in humans and rodents, neuronal type is found almost exclusively in the nervous system. This gaseous molecule is a nonclassical neurotransmitter, which maintains the activities of neural cells and regulates the normal functions of brain. It appears to play a role in promoting the transfer of nerve signals from one neuron to another, maintaining the synaptic strength. Meanwhile, nitric oxide is a unique regulator on neurogenesis and synaptogenesis, producing the positive or negative effects upon different signal pathways or cellular origins and locations. Based on its significant roles in neural plasticity, nitric oxide is involved in a number of central nervous diseases, such as ischemia, depression, anxiety, and Alzheimer's disease. Clarifying the profiles of nitric oxide in the brain tissues and its participation in pathophysiological processes opens a new avenue for development of new therapeutic strategies. Thus, this chapter specifies the effects of nitric oxide in the hippocampus, a key structure implicated in the modulation of mood and memories, exhibiting the trend of future research on nitric oxide.

Sildenafil, a phosphodiesterase type 5 inhibitor, reduces antidepressant-like activity of paroxetine in the forced swim test in mice

BACKGROUND

Sildenafil, a selective phosphodiesterase 5 (PDE5) inhibitor, has recently been reported to influence the antidepressant activity of some antidepressant drugs. The present study was undertaken to investigate the involvement of the nitric oxide/cyclic guanosine 3',5'-monophosphate/PDE5 (NO/cGMP/PDE5) signaling pathway in the antidepressant activity of paroxetine and to assess the interaction between paroxetine and sildenafil, in the forced swim test in mice.

METHODS

Swim trials were conducted by placing mice in glass cylinders filled with water for 6 min. Total behavioral immobility was measured during the last 4 min of the test. Changes in locomotor activity were measured with photoresistor actimeters. Serum and brain paroxetine concentrations were assayed by the HPLC method.

RESULTS

Paroxetine at a dose of 1 mg/kg significantly decreased immobility time in the forced swim test, while sildenafil (5, 10 and 20 mg/kg) in a dose-dependent manner reduced the antidepressant activity of paroxetine. Pharmacokinetic studies did not show any significant changes in paroxetine concentration in serum and brain tissue as compared to paroxetine treatment alone.

CONCLUSIONS

The results suggest that paroxetine may exert its antidepressant action by decreasing cGMP levels and sildenafil, as a drug which has the opposite effect on the processes mediated via the NO/cGMP/PDE5 signaling pathway, may decrease the efficacy of paroxetine. However, the co-administration of paroxetine with sildenafil resulted in a potent reduction (80%) of locomotor activity, which suggests that the reversal of antidepressant action of paroxetine may have been a result of locomotor deficits. Further studies are required to explain the mechanism underlying this phenomenon.

Chronic administration of imipramine but not agomelatine and moclobemide affects the nitrergic relaxation of rabbit corpus cavernosum smooth muscle

Sexual dysfunction is a common and underestimated effect of antidepressants. However, the mechanism by which these drugs cause erectile dysfunction is unclear. We investigated the reactivity of the corpus cavernosum of rabbits that were treated with either chronic imipramine, which is a tricyclic agent; agomelatine, which is a melatonergic agonist and serotonin 5HT(2c) antagonist; or moclobemide, which is a reversible inhibitor of monoamine-oxidase A. Twenty rabbits were randomly divided into four groups: the control group (n=5), the imipramine-treated group (n=5), which received i.p. injections of 10 mg/kg/day of imipramine, the moclobemide-treated group (n=5), which received i.p. injections of 20 mg/kg/day of moclobemide, and the agomelatine-treated group (n=5), which was orally administered 10 mg/kg/day of agomelatine. The reactivities of corpus cavernosum tissue obtained from the antidepressant-treated and the control groups were studied in organ chambers after the animals were subjected to 21 days of drug administration. The acetylcholine-induced endothelium-dependent and the electrical field stimulation (EFS)-induced neurogenic relaxation of the corpus cavernosum of the imipramine-treated group was significantly decreased compared with the control group. However, neither the acetylcholine- nor EFS-induced relaxation was changed in the moclobemide- or agomelatine-treated groups. There were no change in the relaxant response to the nitric oxide (NO) donor sodium nitroprusside and contractile response to KCl between the groups. This study suggests that chronic imipramine treatment but not agomelatine and moclobemide treatments causes significant functional changes in the penile erectile tissue of rabbits and that these changes may contribute to the development of impotence.

Premature ejaculation: do we have effective therapy?

INTRODUCTION

Premature ejaculation (PE) is the most common sexual dysfunction, with the majority of PE patients remaining undiagnosed and undertreated. Despite its prevalence, there is a current paucity of data regarding available treatment options and mechanisms. The objective of the current investigation is to review and summarize pertinent literature on therapeutic options for the treatment of PE, including behavioral/psychologic, oral pharmacotherapy, and surgery.

METHODS

A pubmed search was conducted on articles reporting data on available treatment options for PE. Articles describing potential mechanisms of action were additionally included for review. Preference was given towards randomized, controlled trials, when available.

RESULTS

PE remains an underdiagnosed and undertreated disease process, with limited data available regarding potential underlying mechanisms and long-term outcomes of treatment options. Psychological/behavioral therapies, including the stop-start, squeeze, and pelvic floor rehabilitation techniques have demonstrated improvements in short-term series, with decreased efficacy with additional follow-up. Topical therapies, which are commonly utilized result in prolonged intravaginal ejaculatory latency time (IELT) at the expense of potential penile/vaginal Hypothesia. Oral therapies similarly demonstrate improved IELTs with variable side effect profiles and include selective serotonin reuptake inhibitors (daily or on demand), phosphodiesterase-5 inhibitors, alpha-1 adrenergic antagonists, and tramadol. Alternative therapies such as acupuncture have shown benefits in limited studies. Surgery is not commonly performed and is not recommended by available guidelines.

CONCLUSIONS

PE is a common condition, with limited data available regarding its underlying pathophysiology and treatment. Available therapies include topical, oral, behavioral/psychologic modification, or a combination thereof. Additional research is required to assess the optimal treatment strategies and algorithms as well as to better define the mechanisms for PE and its management.

Effects of Korean ginseng berry extract on sexual function in men with erectile dysfunction: a multicenter, placebo-controlled, double-blind clinical study

Ginseng is beneficial for many aspects of human physiology, including sexual function. In this study, we have evaluated the efficacy and safety of an extract of ginseng berry, which has a ginsenoside profile distinct from other parts of the plant, on sexual function in men with erectile dysfunction. In all, 119 men with mild-to-moderate ED participated in a multicenter, randomized, double-blind, parallel, placebo-controlled clinical study. They were administered 4 tablets of either standardized Korean ginseng berry (SKGB, 350 mg ginseng berry extract per tablet), or placebo, daily, for 8 weeks. Efficacy was assessed with the International Index of Erectile Function (IIEF)-15 and premature ejaculation diagnostic tool (PEDT) at the end of the 4th and 8th week. We observed that the total and each of the individual domain scores of IIEF-15 increased from 40.95 ± 7.05 to 46.19 ± 12.69 significantly in the SKGB by the 8th week (P<0.05). The erectile function domain of IIEF changed slightly from 17.17 ± 2.57 to 18.59 ± 5.99 in the SKGB group by the 8th week (P<0.05). In addition, PEDT scores significantly improved from 9.14 ± 4.57 to 7.97 ± 4.4 and 7.53 ± 4.26 in the SKGB group after 4 and 8 weeks of treatment (P<0.05). Safety markers including hormone and lipid in the blood were assessed at the end of the 4th and 8th week and they remained unchanged. Oral administration of the SKGB extract improved all domains of sexual function. It can be used as an alternative medicine to improve sexual life in men with sexual dysfunction.

New insights on premature ejaculation: a review of definition, classification, prevalence and treatment

There are ongoing debates about the definition, classification and prevalence of premature ejaculation (PE). The first evidence-based definition of PE was limited to heterosexual men with lifelong PE who engage in vaginal intercourse. Unfortunately, many patients with the complaint of PE do not meet these criteria. However, these men can be diagnosed as one of the PE subtypes, namely acquired PE, natural variable PE or premature-like ejaculatory dysfunction. Nevertheless, the validity of these subtypes has not yet been supported by evidence. The absence of a universally accepted PE definition and lack of standards for data acquisition have resulted in prevalence studies that have reported conflicting rates. The very high prevalence of 20%-30% is probably due to the vague terminology used in the definitions at the time when such surveys were conducted. Although many men may complain of PE when questioned for a population-based prevalence study, only a few of them will actively seek treatment for their complaint, even though most of these patients would define symptoms congruent with PE. The complaints of acquired PE patients may be more severe, whereas complaints of patients experiencing premature-like ejaculatory dysfunction seem to be least severe among men with various forms of PE. Although numerous treatment modalities have been proposed for management of PE, only antidepressants and topical anaesthetic creams have currently been proven to be effective. However, as none of the treatment modalities have been approved by the regulatory agencies, further studies must be carried to develop a beneficial treatment strategy for PE.

Inducible nitric oxide synthase is involved in the modulation of depressive behaviors induced by unpredictable chronic mild stress

BACKGROUND

Experiences and inflammatory mediators are fundamental in the provocation of major depressive disorders (MDDs). We investigated the roles and mechanisms of inducible nitric oxide synthase (iNOS) in stress-induced depression.

METHODS

We used a depressive-like state mouse model induced by unpredictable chronic mild stress (UCMS). Depressive-like behaviors were evaluated after 4 weeks of UCMS, in the presence and absence of the iNOS inhibitor N-(3-(aminomethyl)benzyl)acetamidine (1400 W) compared with the control group. Immunohistochemistry was used to check the loss of Nissl bodies in cerebral cortex neurons. The levels of iNOS mRNA expression in the cortex and nitrites in the plasma were measured with real-time reverse transcription PCR (RT-PCR) and Griess reagent respectively.

RESULTS

Results showed that the 4-week UCMS significantly induced depressive-like behaviors, including decreased sucrose preference in a sucrose preference test, increased duration of immobility in a forced swim test, and decreased hole-searching time in a locomotor activity test. Meanwhile, in the locomotor activity test, UCMS had no effect on normal locomotor activities, such as resting time, active time and total travel distance. Furthermore, the levels of iNOS mRNA expression in the cortex and nitrites in the plasma of UCMS-exposed mice were significantly increased compared with that of the control group. Neurons of cerebral cortex in UCMS-exposed mice were shrunken with dark staining, together with loss of Nissl bodies. The above-mentioned stress-related depressive-like behaviors, increase of iNOS mRNA expression in the cortex and nitrites in the plasma, and neuron damage, could be abrogated remarkably by pretreating the mice with an iNOS inhibitor (1400 W). Moreover, neurons with abundant Nissl bodies were significantly increased in the 1400 W + UCMS group.

CONCLUSIONS

These results support the notion that stress-related NO (derived from iNOS) may contribute to depressive-like behaviors in a mouse model, potentially concurrent with neurodegenerative effects within the cerebral cortex.

Chronic administration of fluoxetine impairs neurogenic and endothelium-dependent relaxation of the rabbit corpus cavernosum smooth muscle

Antidepressants, including selective serotonin reuptake inhibitors (SSRIs), cause erectile dysfunction; however, the mechanism by which they cause erectile function is unclear. We investigated the reactivity of the corpus cavernosum after chronic fluoxetine treatment in rabbits. Twelve rabbits were randomly divided into two groups: control (n=6) or 20mg/kg/day of fluoxetine delivered i.p. (n=6). The reactivity of the corpus cavernosum tissue from the fluoxetine-treated and control groups was studied in organ chambers after 21 days of fluoxetine injection. In the fluoxetine-treated group, endothelium-dependent relaxation of the corpus cavernosum in response to acetylcholine was significantly decreased compared to the control group. However, the sensitivity (i.e., pD(2)) of the fluoxetine-treated cavernosal tissue strips to acetylcholine was not changed with respect to controls. Electrical field stimulation (EFS)-induced neurogenic relaxation was also significantly reduced in the fluoxetine-treated group. Relaxation in response to the nitric oxide (NO) donor sodium nitroprusside was similar between the cavernosal tissues from the two groups. There was also no change in agonist potency between the two groups. Additionally, chronic fluoxetine treatment had no effect on KCl-induced contractile responses. When tissue contraction was produced with phenylephrine to study relaxation in response to various stimuli, the tension induced was similar between the fluoxetine-treated and control groups. This study suggests that chronic fluoxetine treatment causes significant functional changes to the penile erectile tissue of rabbits, and these changes may contribute to the development of impotence.

Pulmonary vascular effects of serotonin and selective serotonin reuptake inhibitors in the late-gestation ovine fetus

Maternal use of selective serotonin (5-HT) reuptake inhibitors (SSRIs) is associated with an increased risk for persistent pulmonary hypertension of the newborn (PPHN), but little is known about 5-HT signaling in the developing lung. We hypothesize that 5-HT plays a key role in maintaining high pulmonary vascular resistance (PVR) in the fetus and that fetal exposure to SSRIs increases 5-HT activity and causes pulmonary hypertension. We studied the hemodynamic effects of 5-HT, 5-HT receptor antagonists, and SSRIs in chronically prepared fetal sheep. Brief infusions of 5-HT (3-20 μg) increased PVR in a dose-related fashion. Ketanserin, a 5-HT 2A receptor antagonist, caused pulmonary vasodilation and inhibited 5-HT-induced pulmonary vasoconstriction. In contrast, intrapulmonary infusions of GR127945 and SB206553, 5-HT 1B and 5-HT 2B receptor antagonists, respectively, had no effect on basal PVR or 5-HT-induced vasoconstriction. Pretreatment with fasudil, a Rho kinase inhibitor, blunted the effects of 5-HT infusion. Brief infusions of the SSRIs, sertraline and fluoxetine, caused potent and sustained elevations of PVR, which was sustained for over 60 min after the infusion. SSRI-induced pulmonary vasoconstriction was reversed by infusion of ketanserin and did not affect the acute vasodilator effects of acetylcholine. We conclude that 5-HT causes pulmonary vasoconstriction, contributes to maintenance of high PVR in the normal fetus through stimulation of 5-HT 2A receptors and Rho kinase activation, and mediates the hypertensive effects of SSRIs. We speculate that prolonged exposure to SSRIs can induce PPHN through direct effects on the fetal pulmonary circulation.

A generalist's guide to treating patients with depression with an emphasis on using side effects to tailor antidepressant therapy

This review provides a guide to the primary care physician for diagnosing and managing depression. To identify relevant articles, a PubMed search (ending date parameter, October 15, 2009) was conducted using the keywords depression, antidepressants, side effects, adverse effects, weight gain, sexual dysfunction, and sleep disturbance, and the reference lists of relevant articles were hand searched. This review explores the challenges in diagnosing depression that will and will not respond to antidepressants (ADs) and describes the value of 2-question screening instruments followed by in-depth questioning for positive screening results. It underscores the implications of veiled somatic presentations in which underlying depression is missed, leading to fruitless and expensive medical work-ups. Following this survey of the difficulties in diagnosing depression, the 4 options generalists have for treating a patient with depression are discussed: watchful waiting, antidepressant therapy, psychotherapy, and psychiatric referral. This review proposes that physicians, once they decide to prescribe, use AD side effects to advantage by selecting medications to minimize negative and maximize positive possibilities, thereby improving adherence. It focuses on the 3 most troubling adverse effects-sleep disturbance, sexual dysfunction, and weight gain. It provides AD-prescribing principles to assist primary care physicians in successfully managing depression and appropriately referring patients to a psychiatrist. Antidepressant therapy is not a panacea for treating patients with depression. An approach blending enlightened observation, medications, and psychotherapy often helps depressed patients recover to their former baselines.

Antidepressant-Induced Sexual Dysfunction among Newer Antidepressants in a Naturalistic Setting

OBJECTIVE

Antidepressants used to treat depression are frequently associated with sexual dysfunction. Sexual side effects affect the patient's quality of life and, in long-term treatment, can lead to non-compliance and relapse. However, studies covering many antidepressants with differing mechanisms of action were scarce. The present study assessed and compared the incidence of sexual dysfunction among different antidepressants in a naturalistic setting.

METHODS

Participants were married patients diagnosed with depression, per DSM-IV diagnostic criteria, who had been taking antidepressants for more than 1 month. We assessed the participants via the Arizona Sexual Experiences Scale (ASEX), Beck Depression Inventory (BDI), and State-Trait Anxiety Inventory (STAI), and assessed their demographic variables, types and dosages of antidepressants, and duration of antidepressant use via their medical records.

RESULTS

One hundred and one patients (46 male, 55 female, age 42.2+/-7 years) completed the instruments. Thirteen were taking fluoxetine (mean dose 21.3+/-8.5 mg/day), 24 were taking paroxetine (mean dose 20.4+/-7.2 mg/day), 20 taking citalopram (mean dose 22.1+/-6.5 mg/day), 22, venlafaxine (mean dose 115.7+/-53.2 mg/day) and 22, mirtazapine (mean dose 18+/-8.7 mg/day). Mean ages, sex ratios, and BDI and STAI scores did not differ significantly across antidepressants. A substantial number of participants (46.5%, n=47) experienced sexual dysfunction. The prevalence of sexual dysfunction differed across drugs: citalopram 60% (n=12), venlafaxine 54.5% (n=12), paroxetine 54.2% (n=13), fluoxetine 46.2% (n=6), and mirtazapine 18.2% (n=4). Regression analyses revealed the significant factors for sexual dysfunction were being female, total scores on the BDI and SAI, and type of antidepressant (F=4.92, p<0.0001). Of the antidepressants, the mirtarzapine group's total ASEX score was significantly lower than the scores of the citalopram, fluoxetine, and paroxetine groups.

CONCLUSION

The incidence of sexual dysfunction was substantially high during antidepressant treatment. The incidence of sexual dysfunction differed among antidepressants having different mechanisms of action. Our study suggests the need for clinicians to consider the impact of pharmacotherapy on patients' sexual functioning in the course of treatment with antidepressants.

Nebivolol dilates human penile arteries and reverses erectile dysfunction in diabetic rats through enhancement of nitric oxide signaling

INTRODUCTION

Traditional beta-blockers have sometimes been associated with erectile dysfunction (ED). Nebivolol is a cardioselective β(1)-adrenoceptor antagonist that promotes vasodilation through a nitric oxide (NO)-dependent mechanism.

AIM

We evaluated the effects of nebivolol on the NO/cyclic guanosine monophosphate (cGMP) signaling pathway, on erectile function and dysfunction, and in human penile vascular tissues.

METHODS

Erectile response to cavernosal nerve electrical stimulation in control and diabetes-induced ED rats were evaluated, along with serum nitrite/nitrate (NOx) concentration and plasma/tissue cGMP levels. Endothelium-dependent and sildenafil-induced relaxation of isolated human corpus cavernosum (HCC) and human penile resistance arteries (HPRA) were also determined.

MAIN OUTCOME MEASURES

The effects of nebivolol on erectile function and dysfunction and on NO/cGMP-mediated responses.

RESULTS

Treatment with nebivolol significantly potentiated erectile response in control rats, regardless of its effects on blood pressure. Nebivolol increased NOx and plasma cGMP by 3-fold and 2.75-fold, respectively, and significantly augmented the elevation of plasma cGMP produced by sildenafil. Nebivolol enhanced endothelium-dependent and sildenafil-induced relaxations of HCC tissue, and produced endothelium-dependent vasodilation of HPRA. Nebivolol, but not atenolol, significantly improved erectile response in diabetic rats (51.6%, 53.2%, and 87.1% of response at 3 Hz in nondiabetic rats, for vehicle-treated, atenolol-treated, and nebivolol-treated diabetic rats, respectively); after sildenafil administration, ED was completely reversed in nebivolol-treated diabetic rats (69.6% and 112% for diabetic rats treated with sildenafil and nebivolol plus sildenafil, respectively). Accordingly, nebivolol restored systemic NOx levels and cGMP content in penile tissue from these animals.

CONCLUSIONS

Nebivolol in vivo activated the NO/cGMP pathway, enhanced erectile response and reversed ED in diabetic rats. Moreover, nebivolol in vitro potentiated NO/cGMP-mediated relaxation of human erectile tissues. These effects may account for the low incidence of ED in nebivolol-treated hypertensive patients. Nebivolol therefore may have utility in the treatment of ED, particularly ED associated with diabetes.

How does this happen? Part I: mechanisms of adverse drug reactions associated with psychotropic medications

OBJECTIVE

To review the background and mechanisms behind how certain psychotropic medications cause adverse drug reactions.

METHODS

A literature review pertaining to several interesting and unusual adverse drug reactions attributed to selected psychotropic medications was conducted. These include: 1) QTc interval prolongation secondary to ziprasidone, pimozide, and other antipsychotic agents. 2) Nephrogenic diabetes insipidus and hypernatremia secondary to lithium. 3) Hypothyroidism secondary to lithium. 4) Erectile dysfunction secondary to selective serotonin and serotonin/norepinephrine reuptake inhibitors (SSRIs/SNRIs).

RESULTS

Biochemical mechanisms of how certain psychotropic medications cause adverse drug reactions were reviewed. Specific interventions and monitoring recommendations to prevent or reduce the impact of these adverse reactions are discussed briefly.

CONCLUSION

Knowledge of risk factors and mechanisms of adverse drug reactions with psychotropic medications can help to guide medication prescribing, monitoring and interventions to prevent or mitigate these reactions.

NMDA receptor/nitrergic system blockage augments antidepressant-like effects of paroxetine in the mouse forced swimming test

OBJECTIVE

In this study, we evaluated the involvement of N-methyl-D-aspartate receptor (NMDAR)/nitric oxide (NO) system on the antidepressant-like effects of paroxetine in the mouse forced swimming test.

METHOD

Swim sessions were conducted by placing mice in individual glass cylinders filled with water for 6 min. The duration of behavioral immobility during the last 4 min of the test was evaluated.

RESULTS

Paroxetine (8 and 16 mg/kg, intraperitoneal [i.p.]) significantly reduced the immobility times of mice, whereas lower doses (2 and 4 mg/kg) had no effect. NMDA antagonists MK-801 (0.1 and 0.25 mg/kg, i.p.) and ifenprodil (1 and 3 mg/kg, i.p.) and the NO synthase inhibitor NG-L-arginine methyl ester (L-NAME; 30 and 100 mg/kg, i.p.) significantly decreased the immobility time. Lower doses of MK-801 (0.01 and 0.05 mg/kg), ifenprodil (0.1 and 0.5 mg/kg), and L-NAME (10 mg/kg) had no effect. Combined treatment of subeffective doses of paroxetine (4 mg/kg) and MK-801 (0.05 mg/kg), ifenprodil (0.5 mg/kg), and L-NAME (10 mg/kg) robustly exerted an antidepressant-like effect. The noneffective dose of a NO precursor L: -arginine (750 mg/kg, i.p.) prevented the antidepressant-like effect of paroxetine (30 mg/kg).

CONCLUSION

We suggested, for the first time, a possible role for NMDAR/NO signaling in the antidepressant-like effects of paroxetine, providing a new approach for the treatment of depression.

Selective serotonin reuptake inhibitor-induced sexual dysfunction

INTRODUCTION

Sexual dysfunctions are often present in subjects with mood disturbances; however. antidepressants can induce per se sexual dysfunctions.

AIM

To explore the relationship between the use of selective serotonin reuptake inhibitors (SSRIs), non-SSRIs antidepressants and benzodiazepines (BDZ), hormonal parameters, and reported sexual dysfunction (as assessed by the Structured Interview on Erectile Dysfunction [SIEDY]) in male subjects with comparable psychopathological symptoms (as assessed by the Middlesex Hospital Questionnaire [MHQ] a self-reported test for the screening of mental disorders in a non-psychiatric setting).

METHODS

A consecutive series of 2,040 (mean age 51 +/- 13 years) male patients with sexual dysfunction was studied.

MAIN OUTCOME MEASURES

Several hormonal and biochemical parameters were investigated, along with SIEDY and the MHQ.

RESULTS

Higher prolactin was observed only in patients using SSRIs, whereas no other hormonal difference was found after adjustment for confounders. Use of SSRIs was associated with a twofold risk for patient hypoactive sexual desire and with a higher impairment of reported erectile function. However, no difference in penile blood flow was observed. A very high risk (sevenfold) for delayed ejaculation (DE) was observed in SSRI users. Interestingly, the association with the mild, but not severe, form of DE was observed also in subjects using non-SSRI antidepressants (3.35 [1.48-7.59]; P < 0.005). Different life stressors and relational parameters were also associated with SSRI use. SSRI users reported less enjoyment with masturbation and decreased partner desire and climax. Conversely, a lack of significant association was observed among BDZ or non-SSRI antidepressant users and all the aforementioned life-stressors and relational parameters.

CONCLUSIONS

SSRIs can negatively affect all the steps of the male sexual response cycle (desire-arousal-excitement-orgasm). SSRI-associated sexual dysfunction has a deleterious effect on both auto- and couple-erotic performances. Conversely, other antidepressants and BDZ are less often associated with sexual impairment.

Neuronal nitric oxide synthase: structure, subcellular localization, regulation, and clinical implications

Nitric oxide (NO), a free gaseous signaling molecule, is involved in the regulation of the cardiovascular, nervous and immune system. The neurotransmitter function of nitric oxide is dependent on dynamic regulation of its biosynthetic enzyme, nitric oxide synthase (NOS). There are three types of NOS, neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS). Of the three NOS, we focus on nNOS in the present review. Brain nNOS exists in particulate and soluble forms and the differential subcellular localization of nNOS may contribute to its diverse functions. Proteins bearing PDZ domains can interact directly with the PDZ domain of nNOS, influencing the subcellular distribution and/or activity of the enzyme. During the past several years, an increasing number of reports have demonstrated the importance of nNOS in a variety of synaptic signaling events. nNOS has been implicated in modulating physiological functions such as learning, memory, and neurogenesis, as well as being involved in a number of human diseases. In this review we concentrate on recent findings regarding the structural features, subcellular localization and factors regulating nNOS function. In particular, we conclude with a section discussing the role of nNOS in a wide range of physiological and pathological conditions.

Evaluation of endocrine profile and hypothalamic-pituitary-testis axis in selective serotonin reuptake inhibitor-induced male sexual dysfunction

PURPOSE

To evaluate endocrine profile and hypothalamic-pituitary-testis (HPT) axis in male depressed patients with selective serotonin reuptake inhibitor (SSRI)-induced sexual dysfunction (SDF).

MATERIALS AND METHODS

Eighty-six fertile depressed male patients with SSRI-induced SDF, aged 18 to 50 years, were enrolled in the study (group 1). Sixty-two age-matched depressed fertile patients who currently receive one of the SSRIs but without SDF (group 2), and 68 age-matched healthy fertile men who had never received a psychiatric diagnosis (group 3) served as controls. Pretreatment evaluation included history and physical examination and International Index of Erectile Function. Two blood samples were drawn from each subject at 20-minute intervals for the determination of the resting levels of the following hormones: luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, prolactin, and estradiol. The HPT axis was also assessed using the gonadotropin-releasing hormone test.

RESULTS

The prevalence of hormonal abnormalities in groups 1, 2, and 3 were 83.7% (72), 51.6% (32), and 11.8% (7), respectively (P = 0.001 vs group 1 and 0.007 vs group 2). Compared with normal controls, the subjects taking SSRIs had significantly lower serum levels of LH, FSH, and testosterone. In addition, there were significantly decreased LH and FSH responses to gonadotropin-releasing hormone test in groups 1 and 2 compared with normal controls. Of patients in groups 1 and 2, 68 (79.1%) and 27 (43.5%) had elevated serum levels of prolactin (P = 0.0001 vs group 1 and 0.001 vs group 2).

CONCLUSIONS

Most depressed subjects taking SSRIs with and without SDF had diminished HPT axis function. This should be replicated in further studies.