The use of an antagonist 5-HT2a/c for depression and motor function in Parkinson' disease

German Society of Neurology guidelines for the diagnosis and treatment of cognitive impairment and affective disorders in people with Parkinson's disease: new spotlights on diagnostic procedures and non-pharmacological interventions

BACKGROUND AND OBJECTIVE

Cognitive impairment and dementia as well as affective disorders are common and debilitating syndromes that develop in people with Parkinson's disease (PwPD). The authors summarized recommendations for the 2023 updated German guidelines on "Parkinson's disease" from the German Neurological Society (DGN), focusing on the diagnosis and treatment of these disorders.

METHODS

The recommendations were based on literature reviews, other relevant guidelines, and expert opinions.

RESULTS

Measurements to assess cognitive and affective states were reviewed for psychometric properties, use in routine clinical practice, and availability in German. To improve mild cognitive impairment, cognitive training and physical aerobic training are recommended. To treat Parkinson's disease (PD)-related dementia, cognitive stimulation (as a non-pharmacological intervention) and acetylcholinesterase inhibitors (AChEIs, i.e., rivastigmine) are recommended. Cognitive behavioral therapy is recommended to treat depression, anxiety, and fear of progression. Physical interventions are recommended to treat depression, fatigue, and apathy. Optimized dopaminergic treatment is the first-line pharmacological strategy recommended to manage depression, apathy, anhedonia, fatigue, and mood swings. Major depression can be additionally treated using venlafaxine or desipramine, while moderate depression can be treated pharmacologically according to its clinical phenotype (psychomotor retardation or agitation) and comorbidities (e.g., sleep disturbances, pain). Venlafaxine and nortriptyline can be used to treat anhedonia, while citalopram can be used for anxiety.

CONCLUSIONS

In addition to the updated pharmacological treatment options, new insights into recommendations for standardized diagnostics and non-pharmacological interventions were provided for the German health care system. However, more studies are needed to explore the full potential of non-pharmacological interventions to treat and prevent cognitive impairment and affective disorders.

Case report: Personalizing the use of trazodone in real-world patients: a study of three cases of depression with comorbidities

Depressive disorders are leading contributors to the global mental health-related burden, and they represent a challenge for real-world clinicians, due to the low rates of remission despite the high availability of treatments. Often, depression shows in the context of multiple chronic comorbidities, thus requiring precise and accurate management of pharmacological treatments to avoid interactions and side effects. These criticalities call for the need for new strategies of treatment, which may include new insights into the pharmacological properties of currently available antidepressant drugs, to enhance their efficacy in the different contexts in which depression may arise. Trazodone is the prototype serotonin antagonist/reuptake inhibitor antidepressant (SARI). Due to the malleability granted by its multiple formulations, trazodone is frequently used to treat depression, both as an add-on to other antidepressants and as a monotherapy, with satisfying results. Moreover, its tolerability makes it one of the most prescribed antidepressants in patients with poly-treated comorbid medical illnesses, especially in the elderly. Herein, a case series is presented regarding the use of trazodone in patients with complex comorbid diagnoses or distressing side effects. Each of the three cases has been discussed in three specific Round Tables, involving expert clinicians in the fields of Psychiatry, Neurology, General Practice, and Geriatrics using the Nominal Group Technique. The ideas collected have been used to integrate the cases and the discussion with the intent of facilitating accessibility to the widest audience of physicians and clinical workers in different clinical practice contexts. The final aim of this paper is to promote an increasingly personalized use of trazodone in real-world patients with depression.

Rethinking the role of trazodone in the different depressive dimensions

INTRODUCTION

The efficacy of trazodone for several psychopathologic dimensions of depression has been shown in the literature. Trazodone has been widely used in some clinical contexts (e.g. for insomnia and depression in the elderly). However, the role of trazodone in several aspects of depression is not well known.

AREA COVERED

Eight experts from academic and medical centers across Italy met to identify the difficulties and barriers faced in daily clinical practice in the assessment and management of major depressive disorder and how the use of trazodone could address some unmet needs. The objective of the expert meetings and the present document was to increase knowledge of particular areas of treatment with trazodone.

EXPERT OPINION

Evidence of the role of trazodone in patients affected by major depressive disorder with anxiety symptoms, insomnia, agitation, cognitive deficits, alcohol use disorders, physical comorbidities, and suicide risk has been identified, showing the effectiveness of trazodone in different presentations of major depressive disorder. The main characteristics of patients with depression for whom trazodone seems to be most effective have been identified, providing clinicians with information on possible uses of this drug in such population of patients.

Behind the Mask: Parkinson's Disease and Depression

Parkinson's disease (PD) is a common, prevalent neurodegenerative disease. It is mainly characterized by motor symptoms such as rigidity, tremors, and bradykinesia, but it can also manifest with non-motor symptoms, of which depression is the most frequent. The latter can impair the quality of life, yet it gets overlooked and goes untreated because of the significant overlap in their clinical features, hence making the diagnosis difficult. Furthermore, there is limited data on the availability of appropriate criteria for making the diagnosis of depression in PD patients, as it can occur with varying expressions throughout the course of PD or it can also precede it. This review article has included a brief discussion on the diagnosis of depression in PD patients and their overlapped clinical manifestations. Understanding the mechanisms underlying the disease processes of PD and depression and the pathways interconnecting them gives better knowledge on devising treatment options for the patients. Only studies from Pubmed were included and all other databases were excluded. Studies from the last 50 years were included. Suitable references included in these studies were also extracted. Thus, depression in PD and PD in depression, along with their pharmacological and non-pharmacological treatment options, have been discussed.

Treating depression in clinical practice: new insights on the multidisciplinary use of trazodone

Depression is estimated to be a leading contributor to the global mental health-related burden. The determinants of this huge prevalence lie in the fact that depressive symptoms may be comorbid in a wide variety of disorders, thus complicating and exacerbating their clinical framework. This makes the treatment of depressive symptoms difficult, since many pharmacological interactions should be considered by physicians planning therapy. Hence, depression still represents a challenge for both psychiatrists and other clinicians, in terms of its high rates of relapse and resistance despite well-established protocols. It is also complicated by the well-known latency in its complete response to current antidepressant treatments. In this context, the search for new strategies regarding antidepressant treatment is mandatory. Revising the use of "old" pharmacotherapies by considering their specific features may help to perfecting the treatment of depression, both in its standalone psychiatric manifestation and in the framework of other clinical conditions. Using a nominal group technique approach, the results of a consensus of expert physicians regarding the possible use of trazodone as a valuable strategy for addressing the "real world" unmet needs of depression treatment in different fields (psychiatry, primary care, neurology and geriatrics) is herein provided. This idea is based on the unique characteristics of this drug which delivers a more rapid antidepressant action as compared to other selective serotonin reuptake inhibitors. It also has pharmacodynamic malleability (i.e., the possibility of exerting different effects on depressive symptoms at different dosages) and pharmacokinetic tolerability (i.e., the possibility of being used as an add-on to other antidepressants with scarce interaction and achieving complimentary effects) when used in the milieu of other drugs in treating comorbid depressive symptoms. Moreover, the large number of formulations available permits finite dosage adjustments, and the use of trazodone for specific pathologies, such as dysphagia. Therefore, although additional studies exploring the real-world conditions of antidepressant treatment are warranted, experts agree on the idea that depressive disorder, in both its standalone and its comorbid manifestations, may surely take advantage of the particular characteristics of trazodone, thus attempting to reach the greatest effectiveness in different contexts.

Pharmacological and Non-Pharmacological Treatments for Depression in Parkinson's Disease: An Updated Review

Depression represents one of the most common non-motor disorders in Parkinson's disease (PD) and it has been related to worse life quality, higher levels of disability, and cognitive impairment, thereby majorly affecting not only the patients but also their caregivers. Available pharmacological therapeutic options for depression in PD mainly include selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, and tricyclic antidepressants; meanwhile, agents acting on dopaminergic pathways used for motor symptoms, such as levodopa, dopaminergic agonists, and monoamine oxidase B (MAO-B) inhibitors, may also provide beneficial antidepressant effects. Recently, there is a growing interest in non-pharmacological interventions, including cognitive behavioral therapy; physical exercise, including dance and mind-body exercises, such as yoga, tai chi, and qigong; acupuncture; therapeutic massage; music therapy; active therapy; repetitive transcranial magnetic stimulation (rTMS); and electroconvulsive therapy (ECT) for refractory cases. However, the optimal treatment approach for PD depression is uncertain, its management may be challenging, and definite guidelines are also lacking. It is still unclear which of these interventions is the most appropriate and for which PD stage under which circumstances. Herein, we aim to provide an updated comprehensive review of both pharmacological and non-pharmacological treatments for depression in PD, focusing on recent clinical trials, systematic reviews, and meta-analyses. Finally, we discuss the pharmacological agents that are currently under investigation at a clinical level, as well as future approaches based on the pathophysiological mechanisms underlying the onset of depression in PD.

Clinical Evaluation of Sleep Disorders in Parkinson’s Disease

The paradigm of the framing of Parkinson’s disease (PD) has undergone significant revision in recent years, making this neurodegenerative disease a multi-behavioral disorder rather than a purely motor disease. PD affects not only the “classic” substantia nigra at the subthalamic nuclei level but also the nerve nuclei, which are responsible for sleep regulation. Sleep disturbances are the clinical manifestations of Parkinson’s disease that most negatively affect the quality of life of patients and their caregivers. First-choice treatments for Parkinson’s disease determine amazing effects on improving motor functions. However, it is still little known whether they can affect the quantity and quality of sleep in these patients. In this perspective article, we will analyze the treatments available for this specific clinical setting, hypothesizing a therapeutic approach in relation to neurodegenerative disease state.

Systematic, comprehensive, evidence-based approach to identify neuroprotective interventions for motor neuron disease: using systematic reviews to inform expert consensus

OBJECTIVES

Motor neuron disease (MND) is an incurable progressive neurodegenerative disease with limited treatment options. There is a pressing need for innovation in identifying therapies to take to clinical trial. Here, we detail a systematic and structured evidence-based approach to inform consensus decision making to select the first two drugs for evaluation in Motor Neuron Disease-Systematic Multi-arm Adaptive Randomised Trial (MND-SMART: NCT04302870), an adaptive platform trial. We aim to identify and prioritise candidate drugs which have the best available evidence for efficacy, acceptable safety profiles and are feasible for evaluation within the trial protocol.

METHODS

We conducted a two-stage systematic review to identify potential neuroprotective interventions. First, we reviewed clinical studies in MND, Alzheimer's disease, Huntington's disease, Parkinson's disease and multiple sclerosis, identifying drugs described in at least one MND publication or publications in two or more other diseases. We scored and ranked drugs using a metric evaluating safety, efficacy, study size and study quality. In stage two, we reviewed efficacy of drugs in MND animal models, multicellular eukaryotic models and human induced pluripotent stem cell (iPSC) studies. An expert panel reviewed candidate drugs over two shortlisting rounds and a final selection round, considering the systematic review findings, late breaking evidence, mechanistic plausibility, safety, tolerability and feasibility of evaluation in MND-SMART.

RESULTS

From the clinical review, we identified 595 interventions. 66 drugs met our drug/disease logic. Of these, 22 drugs with supportive clinical and preclinical evidence were shortlisted at round 1. Seven drugs proceeded to round 2. The panel reached a consensus to evaluate memantine and trazodone as the first two arms of MND-SMART.

DISCUSSION

For future drug selection, we will incorporate automation tools, text-mining and machine learning techniques to the systematic reviews and consider data generated from other domains, including high-throughput phenotypic screening of human iPSCs.

Antidepressants Effects on Pain in Parkinson Disease: A Systematic Review

OBJECTIVE

Pain in Parkinson disease (PD) is complex as this symptom can be multifactorial in origin because deficits in dopaminergic but also other neurotransmitters are involved. Pain and depression are increasingly recognized to have clinical importance for the quality of life of people living with PD. This systematic review aims to summarize the existing evidence on the potential benefit of using prescribed antidepressants for decreasing or controlling pain associated with PD.

METHODS

PubMed databases were searched for relevant studies using keywords and our exclusion/inclusion criteria and targeting only randomized placebo-controlled trials for antidepressants in PD.

RESULTS

After screening 108 articles, only 3 focused articles were analyzed. Two of the included studies reported were on nortriptyline and paroxetine antidepressants. Unfortunately, included studies did not align in their outcome measures and did not directly compare the drug groups against each other or the placebo. Therefore, the complex nature of the unaligned outcome measures is inadequate for interpreting the efficacy of antidepressants in treating pain symptoms in PD. The third study focused solely on observing the effects of duloxetine but showed no favorable effects of this drug on pain.

CONCLUSIONS

Prospective studies with a direct comparison of antidepressants and placebo should be conducted, focusing on pain-related scales and questions to understand further the role of antidepressants in treating pain in PD.

Drug Choices and Advancements for Managing Depression in Parkinson's Disease

Depression is a frequent non-motor symptom of Parkinson’s disease (PD), and may even precede the onset of motor symptoms of parkinsonism. Beyond its negative influence on mood, depression in PD is frequently associated with other neuropsychiatric symptoms and with late-stage complications such as dementia. Despite its profound impact on the quality of life and cognitive functioning in PD, depression in PD is often under-recognized and poorly treated.

Pathophysiological studies demonstrated that depression in PD is associated with global dysfunction of interactions between discrete brain areas rather than focal structural or functional abnormalities, and that it is sustained by pathological changes of several neurotransmitter/receptor complexes.

In general, all traditional antidepressants and some dopamine agonists have been found to be safe and well-tolerated to treat depressive symptoms in PD, despite initial warning on worsening of parkinsonism. Available data suggest that the time-course of response differs among antidepressants. Efficacy results from clinical trials with antidepressant in PD are, however, rather uncertain, although pooled analysis suggests a moderate benefit. Several issues may critically impact the results of clinical trials with antidepressants in PD, including the correct psychiatric diagnosis, the overlap of symptoms between depression and PD, and the selection of appropriate end-points and rating scales.

Blue Light Therapy Glasses in Parkinson's Disease: Patients' Experience

Background

Blue light glasses have been introduced as a possible new treatment option to treat sleep disturbances in patients with Parkinson disease (PD). Assessing patient attitudes represents a key step in the road towards formal testing and introduction into clinical practice. Specifically, we aimed to assess how patients experience the use of blue light glasses, aiming to optimise compliance in upcoming clinical trials where these glasses will be tested for efficacy.

Methods

We invited 58 PD patients who had used the blue light glasses for at least one week on a daily basis to complete an online survey about their experiences and self-reported impact. For this purpose, the System Usability Scale was used, supplemented with additional questions about (side)effects. A total of 31 patients (53%) replied.

Results

74% of respondents reported subjective improvements in night-time sleep, daytime sleepiness, depressive symptoms, motor functioning, or a combination thereof. The median score for the System Usability Scale (SUS; 0–100 range, higher scores indicating better performance) was 70.0. A total of 26 patients (84%) had an overall positive attitude towards the technique, with patients rating the glasses with an average score of 6.9 ± 2.0 (SD) out of 10. Except for one patient, all responders would like to continue using the glasses, mostly because they considered it a useful aid.

Conclusion

Blue light therapy appears to have a positive effect on sleep, mood, and motor symptoms in PD. PD patients had an overall positive attitude towards blue light glasses as treatment for sleep disorders.

Efficacy and tolerability of antidepressants in Parkinson's disease: A systematic review and network meta-analysis

OBJECTIVE

To systematically review and analyze the efficacy and tolerability of different antidepressant pharmacologic treatments for depressive symptoms in Parkinson's disease (PD) METHODS: We searched PubMed, EMBASE, Cochrane database (CENTRAL), clinicaltrials.gov, and bibliographies for randomized controlled trials investigating the efficacy of antidepressant medications versus a non-treatment, placebo, or active treatment groups for depressive symptoms in PD. Twenty of 3191 retrieved studies (1893 patients) were included, but not all could be meta-analyzed. We used a random-effects model meta-analysis to compare depression scores between an active drug and placebo or control group then used a network meta-analysis to compare the effectiveness of different antidepressant classes. The primary outcome was the efficacy of different classes of antidepressant medications in PD patients with depressive symptoms, measured by standardized mean difference (SMD) in depression score from baseline compared with control.

RESULTS

Pairwise meta-analysis suggested that type B-selective monoamine oxidase inhibitors (SMD = -1.28, CI = -1.68, -0.88), selective serotonin reuptake inhibitors (SMD = -0.49, CI = -0.93, -0.05), and tricyclics (SMD = -0.83, CI = -1.53, -0.13) are effective antidepressants in PD. Network meta-analysis showed that monoamine oxidase inhibitors had the largest effect on depression in PD (SMD (vs selective serotonin reuptake inhibitors) = -0.78, CI = -1.55, -0.01), but these might not be considered traditional antidepressants given their type B selectivity.

CONCLUSIONS

Although limited by few data, this review suggests that multiple antidepressant classes are potentially efficacious in the treatment of depression in PD, but that further comparative efficacy and tolerability research is needed.

The Treatment of Sleep Disorders in Parkinson's Disease: From Research to Clinical Practice

Sleep disorders (SDs) are one of the most frequent non-motor symptoms of Parkinson’s disease (PD), usually increasing in frequency over the course of the disease and disability progression. SDs include nocturnal and diurnal manifestations such as insomnia, REM sleep behavior disorder, and excessive daytime sleepiness. The causes of SDs in PD are numerous, including the neurodegeneration process itself, which can disrupt the networks regulating the sleep–wake cycle and deplete a large number of cerebral amines possibly playing a role in the initiation and maintenance of sleep. Despite the significant prevalence of SDs in PD patients, few clinical trials on SDs treatment have been conducted. Our aim is to critically review the principal therapeutic options for the most common SDs in PD. The appropriate diagnosis and treatment of SDs in PD can lead to the consolidation of nocturnal sleep, the enhancement of daytime alertness, and the amelioration of the quality of life of the patients.

Neuropsychiatric Issues in Parkinson's Disease

Cognitive and neuropsychiatric symptoms are common in Parkinson's Disease and may surpass motor symptoms as the major factors impacting patient quality of life. The symptoms may be broadly separated into those associated with the disease process and those that represent adverse effects of treatment. Symptoms attributed to the disease arise from pathologic changes within multiple brain regions and are not restricted to dysfunction in the dopaminergic system. Mood symptoms such as depression, anxiety, and apathy are common and may precede the development of motor symptoms by years, while other neuropsychiatric symptoms such as cognitive impairment, dementia, and psychosis are more common in later stages of the disease. Neuropsychiatric symptoms attributed to treatment include impulse control disorders, pathologic use of dopaminergic medications, and psychosis. This manuscript will review the current understanding of neuropsychiatric symptoms in Parkinson's Disease.

Progressive Supranuclear Palsy and Corticobasal Degeneration: Pathophysiology and Treatment Options

OPINION STATEMENT

There are currently no disease-modifying treatments for progressive supranuclear palsy (PSP) or corticobasal degeneration (CBD), and no approved pharmacological or therapeutic treatments that are effective in controlling their symptoms. The use of most pharmacological treatment options are based on experience in other disorders or from non-randomized historical controls, case series, or expert opinion. Levodopa may provide some improvement in symptoms of Parkinsonism (specifically bradykinesia and rigidity) in PSP and CBD; however, evidence is conflicting and where present, benefits are often negligible and short lived. In fact, "poor" response to levodopa forms part of the NINDS-SPSP criteria for the diagnosis of PSP and consensus criteria for the diagnosis of CBD (Lang Mov Disord. 20 Suppl 1:S83-91, 2005; Litvan et al. Neurology. 48:119-25, 1997; Armstrong et al. Neurology. 80(5):496-503, 2013). There is some evidence that intrasalivery gland botulinum toxin is useful in managing problematic sialorrhea and that intramuscular botulinum toxin and baclofen are helpful in reducing dystonia, including blepharospasm. Benzodiazepines may also be useful in managing dystonia. Myoclonus may be managed using levetiracetam and benzodiazepines. Pharmacological agents licensed for Alzheimer's disease (such as acetylcholinesterase inhibitors and N-Methyl-D-aspartate receptor antagonists) have been used off-label in PSP, CBD, and other tauopathies with the aim of improving cognition; however, there is limited evidence that they are effective and risk of adverse effects may outweigh benefits. The use of atypical antipsychotics for behavioural symptoms is not recommended in the elderly or those with demetia associated conditions and most antipsychotics will worsen Parkinsonism. Antidepressants may be useful for behavioral symptoms and depression but are often poorly tolerated due to adverse effects. In the absence of an effective drug treatment to target the underlying cause of CBD and PSP, management should focus on optimizing quality of life, relieving symptoms and assisting patients with their activities of daily living (ADL). Patients should be managed by a multidisciplinary team consisting of neurologists, physiotherapists (PT), occupational therapists (OT), speech and language therapists (SALT), dieticians, ophthalmologists, psychologists, and palliative care specialists.

A Humanized Clinically Calibrated Quantitative Systems Pharmacology Model for Hypokinetic Motor Symptoms in Parkinson's Disease

The current treatment of Parkinson’s disease with dopamine-centric approaches such as L-DOPA and dopamine agonists, although very successful, is in need of alternative treatment strategies, both in terms of disease modification and symptom management. Various non-dopaminergic treatment approaches did not result in a clear clinical benefit, despite showing a clear effect in preclinical animal models. In addition, polypharmacy is common, sometimes leading to unintended effects on non-motor cognitive and psychiatric symptoms. To explore novel targets for symptomatic treatment and possible synergistic pharmacodynamic effects between different drugs, we developed a computer-based Quantitative Systems Pharmacology (QSP) platform of the closed cortico-striatal-thalamic-cortical basal ganglia loop of the dorsal motor circuit. This mechanism-based simulation platform is based on the known neuro-anatomy and neurophysiology of the basal ganglia and explicitly incorporates domain expertise in a formalized way. The calculated beta/gamma power ratio of the local field potential in the subthalamic nucleus correlates well (R² = 0.71) with clinically observed extra-pyramidal symptoms triggered by antipsychotics during schizophrenia treatment (43 drug-dose combinations). When incorporating Parkinsonian (PD) pathology and reported compensatory changes, the computer model suggests a major increase in b/g ratio (corresponding to bradykinesia and rigidity) from a dopamine depletion of 70% onward. The correlation between the outcome of the QSP model and the reported changes in UPDRS III Motor Part for 22 placebo-normalized drug-dose combinations is R² = 0.84. The model also correctly recapitulates the lack of clinical benefit for perampanel, MK-0567 and flupirtine and offers a hypothesis for the translational disconnect. Finally, using human PET imaging studies with placebo response, the computer model predicts well the placebo response for chronic treatment, but not for acute treatment in PD.

Agomelatine for Depression in Parkinson Disease: Additional Effect on Sleep and Motor Dysfunction

Depression and sleep disorders are among the most prevalent nonmotor symptoms of Parkinson disease (PD). Because agomelatine acts as a MT1 and MT2 agonist and as a 5HT2c antagonist, this study was designed to assess the efficacy of agomelatine in treating depressive symptoms in PD patients, and the potential changes both in sleep quality and motor symptoms. Depressed patients with PD were treated with agomelatine for 6 months, and they were evaluated with an array of scales. Completed nocturnal video-polysomnography was performed at baseline and week 12. The efficacy analysis population included 24 patients (12 men). The mean (SD) age was 75.2 (8.3) years. The mean (SD) daily dose of agomelatine was 25.00 (10.43) mg at 24 weeks. No changes in dopamine replacement therapy were made. There was a significant decrease in the 17-item Hamilton Depression Scale score over the course of the study (P < 0.0005). The Scales for Outcomes in Parkinson disease Sleep Questionnaire showed a statistically significant improvement over time in each of its subscales: nighttime sleep (P < 0.005), last month nighttime sleep (P < 0.0005), and daytime sleepiness (P < 0.0005). Surprisingly, changes over time in the motor subscale of Unified Parkinson Disease Rating Scale were statistically significant (P < 0.0005). Periodic limb movements and awakenings measured by polysomnography improved significantly (P < 0.005 and P < 0.05, respectively). We concluded that the use of agomelatine in PD depressed patients may have a considerable therapeutic potential because of its dual action for treating both symptoms of depression and disturbed sleep given its secondary beneficial effects regarding the reduction of extrapyramidal symptoms.

Discovery and Structure-Based Optimization of 6-Bromotryptamine Derivatives as Potential 5-HT2A Receptor Antagonists

5-Hydroxytryptamine type 2A (5-HT_2A) receptor is an important target for developing innovative antipsychotic agents in neuropsychiatric disorder therapies. To search for 5-HT_2A receptor antagonists, a new indole alkaloid termed 6-bromo-N-propionyltryptamine (1), together with one known homologue 6-bromo-N-acetyltryptamine (2) were isolated and identified from a marine bacterium Pseudoalteromonas rubra QD1-2. Compound 1 with an N-propionyl side chain exhibited stronger 5-HT_2A receptor antagonist activity than that of N-acetyl derivative (2), indicating that 6-bromotryptamine analogues with a longer chain acyl group perhaps displayed a more potent capacity to the target. Therefore, a series of new 6-bromotryptamine analogues (3–7) with different chain length of the acyl group (C4–C8) were prepared and evaluated activity against 5-HT_2A receptor. Remarkably, 6-bromo-N-hexanoyltryptamine (5) displayed the most effective inhibitory activity, which was 5-fold stronger than that of the parent compound 1 and showed 70% efficacy of the positive control (ketanserin tartrate).

Antidepressive treatments for Parkinson's disease: A systematic review and meta-analysis

CONTEXT

Depression affects 50-70% of patients with Parkinson's disease resulting in significant comorbidity, executive dysfunction, and poorer quality of life. Divergent results from studies of different treatments preclude definite treatment recommendations.

OBJECTIVE

To perform a systematic review and meta-analysis of published randomized controlled trials (RCTS) evaluating the efficacy of pharmacologic and behavioral interventions, and repetitive transcranial magnetic stimulation (rTMS) for depression among patients with idiopathic Parkinson's disease.

DATA SOURCES

Trial registers and the following databases were searched: PubMed, CINAHL, EMBASE, and PsycInfo. Bibliographies of relevant articles were cross-referenced.

STUDY SELECTION AND DATA EXTRACTION

RCTs comparing pharmacologic, behavioral, or rTMS with a placebo/other drugs or methods with no restrictions on participant age, gender, and duration or setting of treatment were included. Eligibility assessment was performed independently. Identified records were sequentially screened according to eligibility criteria. Differences in mean depression score and 95% confidence intervals were calculated.

RESULTS

A total of 893 idiopathic Parkinson's disease patients with clinical depression across 20 RCTs were included. The overall standard mean difference for all pharmacologic interventions was 0.30 (95% CI -0.00, 0.61, p = 0.054). On stratification, there was a distinct difference in effect between antidepressants (SMD of 0.54, 95%CI 0.24, 0.83, p = 0.000) and non-antidepressants (SMD of -0.29, 95% CI -0.86, 0.29, p = 0.328). Behavioral interventions demonstrated significant efficacy with an effect size of 0.87 (95% CI 0.41, 1.33, p = 0.000).

CONCLUSIONS

This meta-analysis demonstrates that pharmacologic treatment with antidepressant medications, specifically the selective serotonin reuptake inhibitors (SSRIs), and behavioral interventions (CBT) significantly improved depression among Parkinson's disease patients.

Monoamine reuptake inhibitors in Parkinson's disease

The motor manifestations of Parkinson's disease (PD) are secondary to a dopamine deficiency in the striatum. However, the degenerative process in PD is not limited to the dopaminergic system and also affects serotonergic and noradrenergic neurons. Because they can increase monoamine levels throughout the brain, monoamine reuptake inhibitors (MAUIs) represent potential therapeutic agents in PD. However, they are seldom used in clinical practice other than as antidepressants and wake-promoting agents. This review article summarises all of the available literature on use of 50 MAUIs in PD. The compounds are divided according to their relative potency for each of the monoamine transporters. Despite wide discrepancy in the methodology of the studies reviewed, the following conclusions can be drawn: (1) selective serotonin transporter (SERT), selective noradrenaline transporter (NET), and dual SERT/NET inhibitors are effective against PD depression; (2) selective dopamine transporter (DAT) and dual DAT/NET inhibitors exert an anti-Parkinsonian effect when administered as monotherapy but do not enhance the anti-Parkinsonian actions of L-3,4-dihydroxyphenylalanine (L-DOPA); (3) dual DAT/SERT inhibitors might enhance the anti-Parkinsonian actions of L-DOPA without worsening dyskinesia; (4) triple DAT/NET/SERT inhibitors might exert an anti-Parkinsonian action as monotherapy and might enhance the anti-Parkinsonian effects of L-DOPA, though at the expense of worsening dyskinesia.

7-3-Chlorophenypiperazinylalkyl derivatives of 8-alkoxy-purine-2,6-dione as a serotonin receptor ligands with potential antidepressant activity

BACKGROUND

The previous study showed that arylpiperazine can condition affinity to α-adrenoceptors, 5-HT1A/5-HT2A receptors and compounds with arylpiperazine had antidepressant-like effect. The aim of this study was to determine the antidepressant-like activity of new arylpiperazines containing novel 8-alkoxy-purine-2,6-dione fragments.

METHODS

New 3-chloroarylpiperazinylalkyl analogs of 8-alkoxy-purine-2,6-dione and their purine-2,6,8-trione analogs (2-5) were tested for their α1, α2, 5-HT1A,5-HT2A, and 5-HT7 receptor affinities in radioreceptor binding study. Moreover, in search for potential antidepressant properties of these compounds, the forced swim test in mice was conducted.

RESULTS

Compounds 2 and 3 were potent 5-HT1A receptor ligands with Ki within the range on 12-15 nM. All investigated compounds were found to be highly active 5-HT2A receptor (Ki 15-28 nM) and α1 adrenoceptor (Ki 21-89 nM) ligands. In the forced swim test all the compounds showed a significantly activity in spite of their reducing ability of locomotor activity. The most potent effect was produced by compound 4 and 5, which reduced the immobility time in this test in all used doses.

CONCLUSION

In our study the most potent antidepressant-like activity was produced by compounds 4 and 5, which are selective for the 5-HT2A and α1 receptors.

Treatment of the sleep disorders associated with Parkinson's disease

Sleep disorders are common in patients with Parkinson's disease (PD), and preliminary work has suggested viable treatment options for many of these disorders. For rapid eye movement sleep behavior disorder, melatonin and clonazepam are most commonly used, while rivastigmine might be a useful option in patients whose behaviors are refractory to the former. Optimal treatments for insomnia in PD have yet to be determined, but preliminary evidence suggests that cognitive-behavioral therapy, light therapy, eszopiclone, donepezil, and melatonin might be beneficial. Use of the wake-promoting agent modafinil results in significant improvement in subjective measures of excessive daytime sleepiness, but not of fatigue. Optimal treatment of restless legs syndrome and obstructive sleep apnea in PD are not yet established, although a trial of continuous positive airway pressure for sleep apnea was recently completed in PD patients. In those patients with early morning motor dysfunction and disrupted sleep, the rotigotine patch provides significant benefit.

Synergistic effect of 5-HT2A receptor gene and MAOA gene on the negative emotion of patients with depression

OBJECTIVE

To analyse the synergistic effect of polymorphism of the tandem repeat sequence u-VNTR of 5-hydroxytryptamine 2A (5-HT2A) receptor gene and monoamine oxidase A (MAOA) gene on the negative emotion in frontal lobe of patients with depression through functional magnetic resonance imaging (fMRI) technique.

METHODS

Functional magnetic resonance imaging scanning was performed for 72 patients with depression and 70 gender, age-matched healthy people with physical examination under negative emotion recognition task. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was adopted to analyse genotype. The superior, middle and inferior gyrus of bilateral frontal lobe was regarded as the brain region of interest, and then the difference of activation intensity in frontal lobe subregion between control groups and patient groups with different genotypes, and the interaction between the two kinds of polymorphism were compared.

RESULTS

The activation intensity in right frontal middle gyrus of patients with CC genotype increased obviously compared with TT and TC genotype patient groups and TT genotype control group (P<0·01); the activation intensity in right frontal inferior gyrus of patients with CC genotype increased obviously compared with TT and TC genotype patient groups and control groups (P<0·01); the activation intensity in right frontal middle gyrus and left frontal inferior gyrus of patients with MAOA high-activity genotype increased obviously compared with patient and control groups with MAOA low-activity genotype (P<0·01). In sum, there existed synergistic effect of the two genotypes on the activation abnormality of negative emotion recognition in right frontal middle gyrus (F = 6·18, P = 0·029). The negative activation in right frontal middle gyrus of patients with CC+H genotypes increased most obviously (P<0·05).

CONCLUSION

The frontal abnormality of patients with depression had certain 5-HT genetic basis, and 5-HT2A receptor CC allele and MAOA-H genotype had synergistic effect on the activity abnormality when recognizing negative emotion in right frontal middle gyrus of patients with depression.

A meta-analysis of randomised placebo-controlled treatment trials for depression and anxiety in Parkinson's disease

BACKGROUND

Psychopharmacotherapy currently constitutes the first-line treatment for depression and anxiety in Parkinson's disease (PD) however the efficacy of antidepressant treatments in PD is unclear. Several alternative treatments have been suggested as potentially more viable alternatives including dopamine agonists, repetitive transcranial magnetic stimulation, and cognitive behavioural therapy (CBT).

METHOD

A meta-analysis of randomised placebo-controlled trials for depression and/or anxiety in PD was conducted to systematically examine the efficacy of current treatments for depression and anxiety in PD.

RESULTS

Nine trials were included. There was only sufficient data to calculate a pooled effect for antidepressant therapies. The pooled effect of antidepressants for depression in PD was moderate but non-significant (d = .71, 95% CI = -1.33 to 3.08). The secondary effect of antidepressants on anxiety in PD was large but also non-significant (d = 1.13, 95% CI = -.67 to 2.94). Two single-trials of non-pharmacological treatments for depression in PD resulted in significant large effects; Omega-3 supplementation (d = .92, 95% CI = .15 to 1.69) and CBT (d = 1.57, 95% CI = 1.06 to 2.07), and warrant further exploration.

CONCLUSIONS

There remains a lack of controlled trials for both pharmacological and non-pharmacological treatments for depression and anxiety in PD which limits the conclusions which can be drawn. While the pooled effects of antidepressant therapies in PD were non-significant, the moderate to large magnitude of each pooled effect is promising. Non-pharmacological approaches show potential for depression in PD however more research is required.

G protein-coupled receptors revisited: therapeutic applications inspired by synthetic biology

G protein-coupled receptors (GPCRs) mediate the majority of cellular responses to hormones and neurotransmitters within the human body. They have much potential in the emerging field of synthetic biology, which is the rational, systematic design of biological systems with desired functionality. The responsiveness of GPCRs to a plethora of endogenous and exogenous ligands and stimuli make them ideal sensory receptor modules of synthetic gene networks. Such networks can activate target gene expression in response to a specific stimulus. Additionally, because GPCRs are important pharmacological targets of various human diseases, genes encoding their protein/peptide ligands can also be incorporated as target genes of the response output elements of synthetic gene networks. This review aims to critically examine the potential role of GPCRs in constructing therapeutic synthetic gene networks and to discuss various challenges in utilizing GPCRs for synthetic biology applications.

Psychiatric care in Parkinson's disease

OBJECTIVE

Parkinson's disease (PD) is a degenerative and disabling disease in which medical providers focus mainly on ameliorating problems in day-to-day functioning. This review summarizes current knowledge about the efficacy and tolerability of psychopharmacological agents in the treatment of depression, anxiety, psychosis, and insomnia in patients with PD. Recommended or promising nonpharmacological interventions are also reviewed.

METHOD

Studies were identified using computerized searches, with further references obtained from the bibliographies of the reviewed articles.

RESULT

Findings in the research literature provide growing evidence concerning the antidepressant treatment of patients with PD. Psychoeducational interventions for managing depression and anxiety symptoms also appear promising. Music therapy has proven to be particularly effective for patients with PD. Psychosis is common in patients with PD. When psychosis is induced by antiparkinson drugs, a dose reduction can be considered, but it is seldom successful. Patients with PD do not generally tolerate conventional antipsychotic medications, justifying evaluation of newer atypical agents in this population. Cholinesterase inhibitors have also become increasingly important in the treatment of PD in recent years. Finally, insomnia is a very frequent complaint in patients with PD and may also contribute to the development of depression. Patients should be encouraged to improve sleep hygiene and use behavioral interventions. Definitive trials of treatments for sleep disorders in this population are also warranted.

CONCLUSION

Therapeutic approaches to the treatment of PD and its associated psychiatric symptoms must be individualized and may involve a combination of antiparkinson drugs, psychopharmacological treatment, and/or psychotherapeutic interventions.

Blinded prospective evaluation of computer-based mechanistic schizophrenia disease model for predicting drug response

The tremendous advances in understanding the neurobiological circuits involved in schizophrenia have not translated into more effective treatments. An alternative strategy is to use a recently published ‘Quantitative Systems Pharmacology’ computer-based mechanistic disease model of cortical/subcortical and striatal circuits based upon preclinical physiology, human pathology and pharmacology. The physiology of 27 relevant dopamine, serotonin, acetylcholine, norepinephrine, gamma-aminobutyric acid (GABA) and glutamate-mediated targets is calibrated using retrospective clinical data on 24 different antipsychotics. The model was challenged to predict quantitatively the clinical outcome in a blinded fashion of two experimental antipsychotic drugs; JNJ37822681, a highly selective low-affinity dopamine D₂ antagonist and ocaperidone, a very high affinity dopamine D₂ antagonist, using only pharmacology and human positron emission tomography (PET) imaging data. The model correctly predicted the lower performance of JNJ37822681 on the positive and negative syndrome scale (PANSS) total score and the higher extra-pyramidal symptom (EPS) liability compared to olanzapine and the relative performance of ocaperidone against olanzapine, but did not predict the absolute PANSS total score outcome and EPS liability for ocaperidone, possibly due to placebo responses and EPS assessment methods. Because of its virtual nature, this modeling approach can support central nervous system research and development by accounting for unique human drug properties, such as human metabolites, exposure, genotypes and off-target effects and can be a helpful tool for drug discovery and development.