Novel drugs and therapeutic targets for severe mood disorders

Unraveling the role of Slc10a4 in auditory processing and sensory motor gating: Implications for neuropsychiatric disorders?

BACKGROUND

Psychiatric disorders, such as schizophrenia, are complex and challenging to study, partly due to the lack of suitable animal models. However, the absence of the Slc10a4 gene, which codes for a monoaminergic and cholinergic associated vesicular transporter protein, in knockout mice (Slc10a4-/-), leads to the accumulation of extracellular dopamine. A major challenge for studying schizophrenia is the lack of suitable animal models that accurately represent the disorder. We sought to overcome this challenge by using Slc10a4-/- mice as a potential model, considering their altered dopamine levels. This makes them a potential animal model for schizophrenia, a disorder known to be associated with altered dopamine signaling in the brain.

METHODS

The locomotion, auditory sensory filtering and prepulse inhibition (PPI) of Slc10a4-/- mice were quantified and compared to wildtype (WT) littermates. Intrahippocampal electrodes were used to record auditory event-related potentials (aERPs) for quantifying sensory filtering in response to paired-clicks. The channel above aERPs phase reversal was chosen for reliably comparing results between animals, and aERPs amplitude and latency of click responses were quantified. WT and Slc10a4-/- mice were also administered subanesthetic doses of ketamine to provoke psychomimetic behavior.

RESULTS

Baseline locomotion during auditory stimulation was similar between Slc10a4-/- mice and WT littermates. In WT animals, normal auditory processing was observed after i.p saline injections, and it was maintained under the influence of 5 mg/kg ketamine, but disrupted by 20 mg/kg ketamine. On the other hand, Slc10a4-/- mice did not show significant differences between N40 S1 and S2 amplitude responses in saline or low dose ketamine treatment. Auditory gating was considered preserved since the second N40 peak was consistently suppressed, but with increased latency. The P80 component showed higher amplitude, with shorter S2 latency under saline and 5 mg/kg ketamine treatment in Slc10a4-/- mice, which was not observed in WT littermates. Prepulse inhibition was also decreased in Slc10a4-/- mice when the longer interstimulus interval of 100 ms was applied, compared to WT littermates.

CONCLUSION

The Slc10a4-/- mice responses indicate that cholinergic and monoaminergic systems participate in the PPI magnitude, in the temporal coding (response latency) of the auditory sensory gating component N40, and in the amplitude of aERPs P80 component. These results suggest that Slc10a4-/- mice can be considered as potential models for neuropsychiatric conditions.

Suppressive effects of bilobalide on depression-like behaviors induced by chronic unpredictable mild stress in mice

Background: Depression is a psychiatric disorder with depressed mood and even suicide attempts as the main clinical symptoms, and its pathogenesis has not yet been fully elucidated. Brain derived neurotrophic factor (BDNF) plays an important role in the pathogenesis of depression. Purpose: The main aim of the present study was to evaluate the effectiveness and reveal the potential mechanisms of bilobalide (BB) intervention in alleviating depression-like behaviors by using chronic unpredictable mild stress (CUMS) mice via mediating the BDNF pathway. Methods: Behavioral assessments were carried out by using the sucrose preference test (SPT), tail suspension test (TST), and forced swimming test (FST). CUMS mice were randomly divided into 5 groups: CUMS + solvent, CUMS + BB low, CUMS + BB medium, CUMS + BB high and CUMS + fluoxetine. Total serum levels of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6) were measured by ELISA. Expression of TNF-α, IL-6, AKT, GSK3β, β-catenin, Trk-B and BDNF in the mouse hippocampus was assessed by western blotting. Results: BB treatment reduced the levels of pro-inflammatory cytokines (IL-6 and TNF-α) and increased the protein expression of BDNF in the hippocampus region of the CUMS mice. Moreover, BB treatment enhanced the AKT/GSK3β/β-catenin signaling pathway which is downstream of the BDNF receptor Trk-B in the hippocampus of these mice. Conclusions: Overall, the experimental results indicated that BB reverses CUMS-induced depression-like behavior. BB exerts antidepressant-like effects by inhibiting neuroinflammation and enhancing the function of neurotrophic factors.

Glycogen synthase kinase-3: A potential target for diabetes

Elevated circulating glucose level due to β-cell dysfunction has been a key marker of Type-II diabetes. Glycogen synthase kinase-3 (GSK-3) has been recognized as an enzyme involved in the control of glycogen metabolism. Consequently, inhibitors of GSK-3 have been explored for anti-diabetic effects in vitro and in animal models. Further, the mechanisms governing the regulation of this enzyme have been elucidated by means of a combination of structural and cellular biological investigations. This review article examines the structural analysis of GSK-3 as well as molecular modeling reports from numerous researchers in the context of the design and development of GSK-3 inhibitors. This article centers on the signaling pathway of GSK-3 relevant to its potential as a target for diabetes and discusses advancements till date on different molecular modification approaches used by researchers in the development of novel GSK-3 inhibitors as potential therapeutics for the treatment of Type II diabetes.

HCN channel inhibitor induces ketamine-like rapid and sustained antidepressant effects in chronic social defeat stress model

Repeated, long-term (weeks to months) exposure to standard antidepressant medications is required to achieve treatment efficacy. In contrast, acute ketamine quickly improves mood for an extended time. Recent work implicates that hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are involved in mediating ketamine's antidepressant effects. In this study, we directly targeted HCN channels and achieved ketamine-like rapid and sustained antidepressant efficacy. Our in vitro electrophysiological recordings first showed that HCN inhibitor DK-AH 269 (also called cilobradine) decreased the pathological HCN-mediated current (Ih) and abnormal hyperactivity of ventral tegmental area (VTA) dopamine (DA) neurons in a depressive-like model produced by chronic social defeat stress (CSDS). Our in vivo studies further showed that acute intra-VTA or acute systemic administration of DK-AH 269 normalized social behavior and rescued sucrose preference in CSDS-susceptible mice. The single-dose of DK-AH 269, both by intra-VTA microinfusion and intraperitoneal (ip) approaches, could produce an extended 13-day duration of antidepressant-like efficacy. Animals treated with acute DK-AH 269 spent less time immobile than vehicle-treated mice during forced swim test. A social behavioral reversal lasted up to 13 days following the acute DK-AH 269 ip injection, and this rapid and sustained antidepressant-like response is paralleled with a single-dose treatment of ketamine. This study provides a novel ion channel target for acutely acting, long-lasting antidepressant-like effects.

Ethyl pyruvate prevents long-term stress-induced cognitive decline and modulates Akt/GSK-3β signaling

Stress is an inevitable part of life and, simultaneously, a stimulus that can trigger various neuropsychiatric disorders. Therefore, proper stress management is essential for maintaining a healthy life. In this study, we investigated the suppression of stress-induced cognitive deficit by controlling changes in synaptic plasticity caused by stress and confirmed that ethyl pyruvate (EP) has such an effect. Corticosterone, a stress hormone, suppresses long-term potentiation (LTP) in mouse acute hippocampal slices. EP blocked the LTP inhibitory effect of corticosterone by regulating GSK-3β function. Restraint stress for 2 weeks increased the anxiety levels and caused the cognitive decline in the experimental animals. Administration of EP for 14 days did not affect the increase in anxiety caused by stress but improved cognitive decline caused by stress. In addition, the decrease in neurogenesis and synaptic function deficits in the hippocampus, which cause of cognitive decline due to stress, were improved by EP administration. These effects appear via regulation of Akt/GSK-3β signaling, as in in vitro studies. These results suggest that EP prevents stress-induced cognitive decline through the modulation of Akt/GSK-3β-mediated synaptic regulation.

Therapeutic potential of NOX inhibitors in neuropsychiatric disorders

RATIONALE

Neuropsychiatric disorders encompass a broad category of medical conditions that include both neurology as well as psychiatry such as major depressive disorder, autism spectrum disorder, bipolar disorder, schizophrenia as well as psychosis.

OBJECTIVE

NADPH-oxidase (NOX), which is the free radical generator, plays a substantial part in oxidative stress in neuropsychiatric disorders. It is thought that elevated oxidative stress as well as neuroinflammation plays a part in the emergence of neuropsychiatric disorders. Including two linked with membranes and four with subunits of cytosol, NOX is a complex of multiple subunits. NOX has been linked to a significant source of reactive oxygen species in the brain. NOX has been shown to control memory processing and neural signaling. However, excessive NOX production has been linked to cardiovascular disorders, CNS degeneration, and neurotoxicity. The increase in NOX leads to the progression of neuropsychiatric disorders.

RESULT

Our review mainly emphasized the characteristics of NOX and its various mechanisms, the modulation of NOX in various neuropsychiatric disorders, and various studies supporting the fact that NOX might be the potential therapeutic target for neuropsychiatric disorders.

CONCLUSION

Here, we summarizes various pharmacological studies involving NOX inhibitors in neuropsychiatric disorders.

Closing the loop between brain and electrical stimulation: towards precision neuromodulation treatments

One of the most critical challenges in using noninvasive brain stimulation (NIBS) techniques for the treatment of psychiatric and neurologic disorders is inter- and intra-individual variability in response to NIBS. Response variations in previous findings suggest that the one-size-fits-all approach does not seem the most appropriate option for enhancing stimulation outcomes. While there is a growing body of evidence for the feasibility and effectiveness of individualized NIBS approaches, the optimal way to achieve this is yet to be determined. Transcranial electrical stimulation (tES) is one of the NIBS techniques showing promising results in modulating treatment outcomes in several psychiatric and neurologic disorders, but it faces the same challenge for individual optimization. With new computational and methodological advances, tES can be integrated with real-time functional magnetic resonance imaging (rtfMRI) to establish closed-loop tES-fMRI for individually optimized neuromodulation. Closed-loop tES-fMRI systems aim to optimize stimulation parameters based on minimizing differences between the model of the current brain state and the desired value to maximize the expected clinical outcome. The methodological space to optimize closed-loop tES fMRI for clinical applications includes (1) stimulation vs. data acquisition timing, (2) fMRI context (task-based or resting-state), (3) inherent brain oscillations, (4) dose-response function, (5) brain target trait and state and (6) optimization algorithm. Closed-loop tES-fMRI technology has several advantages over non-individualized or open-loop systems to reshape the future of neuromodulation with objective optimization in a clinically relevant context such as drug cue reactivity for substance use disorder considering both inter and intra-individual variations. Using multi-level brain and behavior measures as input and desired outcomes to individualize stimulation parameters provides a framework for designing personalized tES protocols in precision psychiatry.

Discovery of a Series of Substituted 1H-((1,2,3-Triazol-4-yl)methoxy)pyrimidines as Brain Penetrants and Potent GluN2B-Selective Negative Allosteric Modulators

Herein, we describe a series of substituted 1H-((1,2,3-triazol-4-yl)methoxy)pyrimidines as potent GluN2B negative allosteric modulators. Exploration of several five- and six-membered heterocycles led to the identification of O-linked pyrimidine analogues that possessed a balance of potency and desirable ADME profiles. Due to initial observations of metabolic saturation, early metabolite identification studies were conducted on compound 18, and the results drove further iterative optimization efforts to avoid the formation of undesired saturating metabolites. The comprehensive investigation of substitution on the pyrimidine moiety of the 1H-1,2,3-triazol-4-yl)methoxy)pyrimidines allowed for the identification of compound 31, which demonstrated high GluN2B receptor affinity, improved solubility, and a clean cardiovascular profile. Compound 31 was profiled in an ex vivo target engagement study in rats at a 10 mg/kg oral dose and achieved an ED₅₀ of 1.7 mg/kg.

The Role of fMRI in Drug Development: An Update

Functional magnetic resonance imaging (fMRI) of the brain is a technology that holds great potential for increasing the efficiency of drug development for the central nervous system (CNS). In preclinical studies and both early- and late-phase human trials, fMRI has the potential to improve cross-species translation of drug effects, help to de-risk compounds early in development, and contribute to the portfolio of evidence for a compound's efficacy and mechanism of action. However, to date, the utilization of fMRI in the CNS drug development process has been limited. The purpose of this chapter is to explore this mismatch between potential and utilization. This chapter provides introductory material related to fMRI and drug development, describes what is required of fMRI measurements for them to be useful in a drug development setting, lists current capabilities of fMRI in this setting and challenges faced in its utilization, and ends with directions for future development of capabilities in this arena. This chapter is the 5-year update of material from a previously published workshop summary (Carmichael et al., Drug DiscovToday 23(2):333-348, 2018).

Benzimidazolium Salts Containing Trifluoromethoxybenzyl: Synthesis, Characterization, Crystal Structure, Molecular Docking Studies and Enzymes Inhibitory Properties

The method for producing 4-trifluoromethoxybenzyl substituted benzimidazolium salts is described in this article. The method is based on the reaction of 4-trifluoromethoxybenzyl substituent alkylating agent with 1-alkylbenzimidazole. This method yielded 1-(4-trifluoromethoxybenzyl)-3-alkylbenzimidazolium bromide salts. These benzimidazolium salts were characterized by using ¹ H-NMR, ¹³ C-NMR, FT-IR spectroscopy, and elemental analysis techniques. The crystal structure of 1f was enlightened by single crystal X-ray diffraction studies. Also, the enzyme inhibition effects of the synthesised compounds were investigated. They demonstrated highly potent inhibition effect on acetylcholinesterase (AChE) and carbonic anhydrases (hCAs) (K_i values are in the range of 7.24±0.99 to 39.12±5.66 nM, 5.57±0.96 to 43.07±11.76 nM, and 4.38±0.43 to 18.68±3.60 nM for AChE, hCA I, and hCA II, respectively). In molecular docking study, the interactions of active compounds showing activity against AChE and hCAs enzymes were examined. The most active compound 1f has -10.90 kcal/mol binding energy value against AChE enzyme, and the potential structure compound 1e, which has activity against hCA I and hCA II enzymes, was -7.51 and -8.93 kcal/mol, respectively.

Second messengers and their importance for novel drug treatments of patients with bipolar disorder

Second messenger systems, like the cyclic nucleotide, glycogen synthase kinase-3β, phosphoinositide, and arachidonic acid cascades, are involved in bipolar disorder (BD). We investigated their role on the development of novel therapeutic drugs using second messenger mechanisms. PubMed search and narrative review. We used all relevant keywords for each second messenger cascade combining it with BD and related terms and combined all with novel/innovative treatments/drugs. Our search produced 31 papers most were reviews, and focussed on the PI3K/AKT-GSK-3β/Nrf2-NF-ĸB pathways. Only two human randomized clinical trials were identified, of ebselen, an antioxidant, and celecoxib, a cyclooxygenase-2 inhibitor, both with poor unsatisfactory results. Despite the fact that all second messenger systems are involved in the pathophysiology of BD, there are few experiments with novel drugs using these mechanisms. These mechanisms are a neglected and potentially major opportunity to transform the treatment of bipolar illness.

Occurrence, hazard, and risk of psychopharmaceuticals and illicit drugs in European surface waters

This study aimed to provide insights into the risk posed by psychopharmaceuticals and illicit drugs in European surface waters, and to identify current knowledge gaps hampering this risk assessment. First, the availability and quality of data on the concentrations of psychopharmaceuticals and illicit drugs in surface waters (occurrence) and on the toxicity to aquatic organisms (hazard) were reviewed. If both occurrence and ecotoxicity data were available, risk quotients (risk) were calculated. Where abundant ecotoxicity data were available, a species sensitivity distribution (SSD) was constructed, from which the hazardous concentration for 5% of the species (HC₅) was derived, allowing to derive integrated multi-species risks. A total of 702 compounds were categorised as psychopharmaceuticals and illicit drugs based on a combination of all 502 anatomical therapeutic class (ATC) 'N' pharmaceuticals and a list of illicit drugs according to the Dutch Opium Act. Of these, 343 (49%) returned occurrence data, while only 105 (15%) returned ecotoxicity data. Moreover, many ecotoxicity tests used irrelevant endpoints for neurologically active compounds, such as mortality, which may underestimate the hazard of psychopharmaceuticals. Due to data limitations, risks could only be assessed for 87 (12%) compounds, with 23 (3.3%) compounds indicating a potential risk, and several highly prescribed drugs returned neither occurrence nor ecotoxicity data. Primary bottlenecks in risk calculation included the lack of ecotoxicity data, a lack of diversity of test species and ecotoxicological end points, and large disparities between well studied and understudied compounds for both occurrence and toxicity data. This study identified which compounds merit concern, as well as the many compounds that lack the data for any calculation of risk, driving research priorities. Despite the large knowledge gaps, we concluded that the presence of a substantial part (26%) of data-rich psychopharmaceuticals in surface waters present an ecological risk for aquatic non-target organisms.

Hemispheric asymmetry of motor cortex excitability in mood disorders - Evidence from a systematic review and meta-analysis

OBJECTIVE

Mood disorders have been associated with lateralized brain dysfunction, on the left-side for depression and right-side for mania. Consistently, asymmetry of cortical excitability, as measured by transcranial magnetic stimulation (TMS) has been reported. Here, we reviewed and summarized work assessing such measures bilaterally in mood disorders.

METHODS

We performed a systematic review and extracted data to perform meta-analyses of interhemispheric asymmetry of motor cortex excitability, assessed with TMS, across different mood disorders and in healthy subjects. Additionally, potential predictors of interhemispheric asymmetry were explored.

RESULTS

Asymmetry of resting motor threshold (MT) among healthy volunteers was significant, favoring lower right relative to left-hemisphere excitability. MT was also significantly asymmetric in major depressive disorder (MDD), but with lower excitability of the left -hemisphere, when compared to the right, no longer observed in recovered patients. Findings on intracortical facilitation were similar. The few trials including bipolar depression revealed similar trends for imbalance, but with lower right hemisphere excitability, relative to the left.

CONCLUSIONS

There is interhemispheric asymmetry of motor cortical excitability in MDD, with lower excitability on left when compared to right-side. Interhemispheric asymmetry, with lower right relative to left-sided excitability, was found for bipolar depression and was also suggested for healthy volunteers, in a pattern that is clearly distinct from MDD.

SIGNIFICANCE

Mood disorders display asymmetric motor cortical excitability that is distinct from that found in healthy volunteers, supporting the presence of lateralized brain dysfunction in these disorders.

Functional neuroanatomy of mania

Mania, the diagnostic hallmark of bipolar disorder, is an episodic disturbance of mood, sleep, behavior, and perception. Improved understanding of the neurobiology of mania is expected to allow for novel avenues to address current challenges in its diagnosis and treatment. Previous research focusing on the impairment of functional neuronal circuits and brain networks has resulted in heterogenous findings, possibly due to a focus on bipolar disorder and its several phases, rather than on the unique context of mania. Here we present a comprehensive overview of the evidence regarding the functional neuroanatomy of mania. Our interpretation of the best available evidence is consistent with a convergent model of lateralized circuit dysfunction in mania, with hypoactivity of the ventral prefrontal cortex in the right hemisphere, and hyperactivity of the amygdala, basal ganglia, and anterior cingulate cortex in the left hemisphere of the brain. Clarification of dysfunctional neuroanatomic substrates of mania may contribute not only to improve understanding of the neurobiology of bipolar disorder overall, but also highlights potential avenues for new circuit-based therapeutic approaches in the treatment of mania.

The Role of Mitochondria in Mood Disorders: From Physiology to Pathophysiology and to Treatment

Mitochondria are cellular organelles involved in several biological processes, especially in energy production. Several studies have found a relationship between mitochondrial dysfunction and mood disorders, such as major depressive disorder and bipolar disorder. Impairments in energy production are found in these disorders together with higher levels of oxidative stress. Recently, many agents capable of enhancing antioxidant defenses or mitochondrial functioning have been studied for the treatment of mood disorders as adjuvant therapy to current pharmacological treatments. A better knowledge of mitochondrial physiology and pathophysiology might allow the identification of new therapeutic targets and the development and study of novel effective therapies to treat these specific mitochondrial impairments. This could be especially beneficial for treatment-resistant patients. In this article, we provide a focused narrative review of the currently available evidence supporting the involvement of mitochondrial dysfunction in mood disorders, the effects of current therapies on mitochondrial functions, and novel targeted therapies acting on mitochondrial pathways that might be useful for the treatment of mood disorders.

Antidepressant and anti-amnesic effects of the aqueous lyophilisate of the leaves of Leptadenia arborea on an animal model of cognitive deficit associated depression

Leptadenia arborea (Asclepiadaceae) is a plant used in traditional medicine to treat syphilis, migraine, and mental illnesses. The aim of our study was to investigate possible antidepressant and anti-amnesic effects of the aqueous lyophilisate of the leaves of Leptadenia arborea in an animal model of cognitive deficit associated depression. Swiss albino adult mice of both sexes were used for this study. A 14-day combined stress model was used to induce depression with early cognitive deficits. The forced swimming test, the open field test and plasma corticosterone level were used to assess antidepressant-like effect. The novel object recognition task (NORT), the Morris Water Maze (MWM) and neurochemical analysis of hippocampal acetylcholinesterase activity was also carried out to assess memory integrity. The aqueous lyophelisate of L. arborea increased swimming time and decreased immobility time in the forced swimming test. In the open field test they was no difference in the number of lines crossed between groups, and the lyophilisate-treated mice spent more time in the centre compared to the control. The lyophilisate decreased the plasma level of corticosterone compared to the control. The lyophilisate decreased the latency to reach the hidden platform and increased the time spent in the target quadrant in the MWM. The lyophilisate also increased the time of exploration of the novel object in the NORT and decreased the acetylcholinesterase activity in the hippocampus. L. arborea effects were decreased when it was co-administered with pCPA. Results suggest that the aqueous lyophilisate of the leaves of L. arborea possess antidepressant-like and anti-amnesic effects.

Ginkgolide-Platinum(II) Complex GPt(II) Exhibits Therapeutic Effect on Depression in Mice via Upregulation of DA and 5-HT Neurotransmitters

Background

Depression is the 5^th most prevalent disorder adversely affecting the health of humans worldwide. The present study evaluated the antidepressant effect of ginkgolide-platinum(II) complex in vivo in a mice model of CMS-induced depression.

Material/Methods

Depression was induced in mice by social isolation followed by chronic mild stress. After stress, the mice were assigned randomly to a model group, a 3 mg/kg group, a 6 mg/kg group, and a 12 mg/kg group. The mice in the 3 treatment groups were intraperitoneally injected with a single dose of 3.0, 6.0, or 12.0 mg/kg GPt(II) on day 11 of stress. The behavioral changes in mice were analyzed on day 21 of GPt(II) treatment by suspension and open field tests.

Results

The GPt(II) treatment significantly increased the numbers of crossings and rearings in CMS mice. Treatment of mice with GPt(II) significantly elevated dopamine, BDNF, and serotonin levels in hippocampus tissues. The CMS-mediated reduction of neuropeptide production in the hippocampus tissues was significantly alleviated by GPt(II) treatment (P<0.05). The GPt(II) treatment suppressed the effect on CMS-induced elevated level of MAO-A in hippocampus tissues. Treatment with GPt(II) significantly repressed caspase-3 activation induced by CMS in the hippocampus tissues of mice. The GPt(II) treatment significantly (P<0.05) upregulated Hsp70 mRNA level in depression model mice. The levels of dopamine, serotonin, and BDNF were increased from 187.83±8.53, 289.65±10.76, and 7.98±1.87 ng/g, respectively, in the model group to 657.63±24.47, 720.54±28.09, and 22.56±3.11 ng/g, respectively, in the 12 mg/kg GPt(II) treatment group.

Conclusions

GPt(II) treatment significantly relieved characteristics of depression in the mice through upregulation of neurotransmitter, neuropeptide, and Hsp70 expression. Moreover, GPt(II) downregulated monoamine oxidase-A levels in the mouse hippocampus tissues. Therefore, further research is warranted on the possible therapeutic effect of GPt(II) in the treatment of depression.

The Relationship between DNA Methylation and Antidepressant Medications: A Systematic Review

Major depressive disorder (MDD) is the leading cause of disability worldwide and is associated with high rates of suicide and medical comorbidities. Current antidepressant medications are suboptimal, as most MDD patients fail to achieve complete remission from symptoms. At present, clinicians are unable to predict which antidepressant is most effective for a particular patient, exposing patients to multiple medication trials and side effects. Since MDD’s etiology includes interactions between genes and environment, the epigenome is of interest for predictive utility and treatment monitoring. Epigenetic mechanisms of antidepressant medications are incompletely understood. Differences in epigenetic profiles may impact treatment response. A systematic literature search yielded 24 studies reporting the interaction between antidepressants and eight genes (BDNF, MAOA, SLC6A2, SLC6A4, HTR1A, HTR1B, IL6, IL11) and whole genome methylation. Methylation of certain sites within BDNF, SLC6A4, HTR1A, HTR1B, IL11, and the whole genome was predictive of antidepressant response. Comparing DNA methylation in patients during depressive episodes, during treatment, in remission, and after antidepressant cessation would help clarify the influence of antidepressant medications on DNA methylation. Individuals’ unique methylation profiles may be used clinically for personalization of antidepressant choice in the future.

Anxiolytic Effect of Essential Oils and Their Constituents: A Review

Essential oils are usually used in aromatherapy to alleviate anxiety symptoms. In comparison to traditional drugs, essential oils have fewer side effects and more diversified application ways, including inhalation. This review provides a comprehensive overview of studies on anxiolytic effects of essential oils in preclinical and clinical trials. Most of the essential oils used in clinical studies have been proven to be anxiolytic in animal models. Inhalation and oral administration were two common methods for essential oil administration in preclinical and clinical trials. Massage was only used in the clinical trials, while intraperitoneal injection was only used in the preclinical trails. In addition to essential oils that are commonly used in aromatherapy, essential oils from many folk medicinal plants have also been reported to be anxiolytic. More than 20 compounds derived from essential oils have shown an anxiolytic effect in rodents, while two-thirds of them are alcohols and terpenes. Monoamine neurotransmitters, amino acid neurotransmitters, and the hypothalamic-pituitary-adrenal axis are thought to play important roles in the anxiolytic effects of essential oils.

Ketamine applications beyond anesthesia - A literature review

Ketamine's clinical use began in the 1970s. Physicians benefited from its safety and ability to induce short-term anesthesia and analgesia. The psychodysleptic effects caused by the drug called its further clinical use into question. Despite these unpleasant effects, ketamine is still applied in veterinary medicine, field medicine, and specialist anesthesia. Recent intensive research brought into light new possible applications of this drug. It began to be used in acute, chronic and cancer pain management. Most interesting reports come from research on the antidepressive and antisuicidal properties of ketamine giving hope for the creation of an effective treatment for major depressive disorder. Other reports highlight the possible use of ketamine in treating addiction, asthma and preventing cancer growth. Besides clinical use, the drug is also applied to in animal model of schizophrenia. It seems that nowadays, with numerous possible applications, the use of ketamine has returned; to its former glory. Nevertheless, the drug must be used with caution because still the mechanisms by which it executes its functions and long-term effects of its use are not fully known. This review aims to discuss the well-known and new promising applications of ketamine.

The inhibition of BDNF/TrkB/PI3K/Akt signal mediated by AG1601 promotes apoptosis in malignant glioma

Malignant glioma is the most aggressive primary brain tumor and has a poor survival rate. Even if extensive methods are preformed to treat glioma, the mortality rate is still very high. It is necessary for discovering and developing new drugs for malignant glioma treatment. AG1601 is one of AG-series drugs, including AG1031 and AG1503, and it has been optimized on the original basis. In our study, we found that AG1601 markedly inhibited proliferation and promoted C6 glioma cell apoptosis in vitro. AG1601 also reduced the size and weight of glioma in vivo. The growth ability of glioma was significantly inhibited after treatment with AG1601. It also showed that the expression levels of BDNF/TrkB/PI3K/Akt signal related proteins were obviously decreased in C6 glioma cells after treatment with AG1601 in vivo and in vitro. We also found that BDNF, as the activator of BDNF/TrkB/PI3K/Akt signal, reversed the anti-proliferation and pro-apoptosis of C6 glioma cells caused by AG1601. K252a, a specific inhibitor of TrkB, and AG1601 in combination aggravated C6 glioma cell apoptosis. These results indicate that AG1601 has good effects on the anti-proliferation and pro-apoptosis of malignant glioma via BDNF/TrkB/PI3K/Akt signal and could be considered as a potential drug in treating malignant glioma.

NV-5138 as a fast-acting antidepressant via direct activation of mTORC1 signaling

Growing evidence implicates altered mTORC1 signaling cascades in the pathophysiology of depression, suggesting that direct modulation of mTORC1 signaling may offer novel therapeutic potential. In this issue of the JCI, Kato and colleagues reported that administration of NV-5138, a recently developed synthetic leucine analog, has a rapid and sustained antidepressant action in rat models via activation of mTORC1 signaling. The investigators also found that the antidepressant effect of NV-5138 is mediated by upregulation of brain-derived neurotrophic factor (BDNF) signaling and that NV-5138 treatment produces rapid synaptic responses in the medial prefrontal cortex. These findings highlight the direct activation of mTORC1 signaling as a potential pharmacological intervention for the treatment of depression.

JHU-083 selectively blocks glutaminase activity in brain CD11b+ cells and prevents depression-associated behaviors induced by chronic social defeat stress

There are a number of clinically effective treatments for stress-associated psychiatric diseases, including major depressive disorder (MDD). Nonetheless, many patients exhibit resistance to first-line interventions calling for novel interventions based on pathological mechanisms. Accumulating evidence implicates altered glutamate signaling in MDD pathophysiology, suggesting that modulation of glutamate signaling cascades may offer novel therapeutic potential. Here we report that JHU-083, our recently developed prodrug of the glutaminase inhibitor 6-diazo-5-oxo-L-norleucine (DON) ameliorates social avoidance and anhedonia-like behaviors in mice subjected to chronic social defeat stress (CSDS). JHU-083 normalized CSDS-induced increases in glutaminase activity specifically in microglia-enriched CD11b⁺ cells isolated from the prefrontal cortex and hippocampus. JHU-083 treatment also reverses the CSDS-induced inflammatory activation of CD11b⁺ cells. These results support the importance of altered glutamate signaling in the behavioral abnormalities observed in the CSDS model, and identify glutaminase in microglia-enriched CD11b⁺ cells as a pharmacotherapeutic target implicated in the pathophysiology of stress-associated psychiatric conditions such as MDD.

Depression as a Neuroendocrine Disorder: Emerging Neuropsychopharmacological Approaches beyond Monoamines

Depression is currently recognized as a crucial problem in everyday clinical practice, in light of ever-increasing rates of prevalence, as well as disability, morbidity, and mortality related to this disorder. Currently available antidepressant drugs are notoriously problematic, with suboptimal remission rates and troubling side-effect profiles. Their mechanisms of action focus on the monoamine hypothesis for depression, which centers on the disruption of serotonergic, noradrenergic, and dopaminergic neurotransmission in the brain. Nevertheless, views on the pathophysiology of depression have evolved notably, and the comprehension of depression as a complex neuroendocrine disorder with important systemic implications has sparked interest in a myriad of novel neuropsychopharmacological approaches. Innovative pharmacological targets beyond monoamines include glutamatergic and GABAergic neurotransmission, brain-derived neurotrophic factor, various endocrine axes, as well as several neurosteroids, neuropeptides, opioids, endocannabinoids and endovanilloids. This review summarizes current knowledge on these pharmacological targets and their potential utility in the clinical management of depression.

Psychedelics Promote Structural and Functional Neural Plasticity

Atrophy of neurons in the prefrontal cortex (PFC) plays a key role in the pathophysiology of depression and related disorders. The ability to promote both structural and functional plasticity in the PFC has been hypothesized to underlie the fast-acting antidepressant properties of the dissociative anesthetic ketamine. Here, we report that, like ketamine, serotonergic psychedelics are capable of robustly increasing neuritogenesis and/or spinogenesis both in vitro and in vivo. These changes in neuronal structure are accompanied by increased synapse number and function, as measured by fluorescence microscopy and electrophysiology. The structural changes induced by psychedelics appear to result from stimulation of the TrkB, mTOR, and 5-HT2A signaling pathways and could possibly explain the clinical effectiveness of these compounds. Our results underscore the therapeutic potential of psychedelics and, importantly, identify several lead scaffolds for medicinal chemistry efforts focused on developing plasticity-promoting compounds as safe, effective, and fast-acting treatments for depression and related disorders.

The Melatonin Signaling Pathway in a Long-Term Memory In Vitro Study

The activation of cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) via phosphorylation in the hippocampus is an important signaling mechanism for enhancing memory processing. Although melatonin is known to increase CREB expression in various animal models, the signaling mechanism between melatonin and CREB has been unknown in vitro. Thus, we confirmed the signaling pathway between the melatonin receptor 1 (MT1) and CREB using melatonin in HT-22 cells. Melatonin increased MT1 and gradually induced signals associated with long-term memory processing through phosphorylation of Raf, ERK, p90RSK, CREB, and BDNF expression. We also confirmed that the calcium, JNK, and AKT pathways were not involved in this signaling pathway by melatonin in HT-22 cells. Furthermore, we investigated whether melatonin regulated the expressions of CREB-BDNF associated with long-term memory processing in aged HT-22 cells. In conclusion, melatonin mediated the MT1-ERK-p90RSK-CREB-BDNF signaling pathway in the in vitro long-term memory processing model and increased the levels of p-CREB and BDNF expression in melatonin-treated cells compared to untreated HT-22 cells in the cellular aged state. Therefore, this paper suggests that melatonin induces CREB signaling pathways associated with long-term memory processing in vitro.

The role of fMRI in drug development

Functional magnetic resonance imaging (fMRI) has been known for over a decade to have the potential to greatly enhance the process of developing novel therapeutic drugs for prevalent health conditions. However, the use of fMRI in drug development continues to be relatively limited because of a variety of technical, biological, and strategic barriers that continue to limit progress. Here, we briefly review the roles that fMRI can have in the drug development process and the requirements it must meet to be useful in this setting. We then provide an update on our current understanding of the strengths and limitations of fMRI as a tool for drug developers and recommend activities to enhance its utility.

Capturing the metastable state in the spontaneous and reversible single-crystal-to-single-crystal phase transition of riluzolium oxalate

A spontaneous and reversible single-crystal-to-single-crystal (SCSC) polymorphic transition via a disordered state has been captured in riluzolium oxalate salt.

Translational Significance of Selective Estrogen Receptor Modulators in Psychiatric Disorders

Accumulating data from various clinical trial studies suggests that adjuvant therapy with ovarian hormones (estrogens) could be effective in reducing cognitive deficit and psychopathological symptoms in women with psychiatric disorders. However, estrogen therapy poses serious limitations and health issues including feminization in men and increased risks of thromboembolism, hot flashes, breast hyperplasia, and endometrium hyperplasia when used for longer duration in older women (aged ≥ 60 years) or in women who have genetic predispositions. On the other hand, selective estrogen receptor modulators (SERMs), which may (or may not) carry some risks of hot flashes, thromboembolism, breast hyperplasia, and endometrial hyperplasia, are generally devoid of feminization effect. In clinical trial studies, adjuvant therapy with tamoxifen, a triphenylethylene class of SERM, has been found to reduce the frequency of manic episodes in patients with bipolar disorder, whereas addition of raloxifene, a benzothiophene class of SERM, to regular doses of antipsychotic drugs has been found to reduce cognitive deficit and psychological symptoms in men and women with schizophrenia, including women with treatment refractory psychosis. These outcomes together with potent neurocognitive, neuroprotective, and cardiometabolic properties suggest that SERMs could be the potential targets for designing effective and safer therapies for psychiatric disorders.

Dextromethorphan/quinidine pharmacotherapy in patients with treatment resistant depression: A proof of concept clinical trial

BACKGROUND

At least one-third of patients with major depressive disorder (MDD) have treatment-resistant depression (TRD), defined as lack of response to two or more adequate antidepressant trials. For these patients, novel antidepressant treatments are urgently needed.

METHODS

The current study is a phase IIa open label clinical trial examining the efficacy and tolerability of a combination of dextromethorphan (DM) and the CYP2D6 enzyme inhibitor quinidine (Q) in patients with TRD. Dextromethorphan acts as an antagonist at the glutamate N-methyl-d-aspartate (NMDA) receptor, in addition to other pharmacodynamics properties that include activity at sigma-1 receptors. Twenty patients with unipolar TRD who completed informed consent and met all eligibility criteria we enrolled in an open-label study of DM/Q up to 45/10mg by mouth administered every 12h over the course of a 10-week period, and constitute the intention to treat (ITT) sample. Six patients discontinued prior to study completion.

RESULTS

There was no treatment-emergent suicidal ideation, psychotomimetic or dissociative symptoms. Montgomery-Asberg Depression Rating Scale (MADRS) score was reduced from baseline to the 10-week primary outcome (mean change: -13.0±11.5, t₁₉=5.0, p<0.001), as was QIDS-SR score (mean change: -5.9±6.6, t₁₉=4.0, p<0.001). The response and remission rates in the ITT sample were 45% and 35%, respectively.

LIMITATIONS

Open-label, proof-of-concept design.

CONCLUSIONS

Herein we report acceptable tolerability and preliminary efficacy of DM/Q up to 45/10mg administered every 12h in patients with TRD. Future larger placebo controlled randomized trials in this population are warranted.

Genistein, a dietary soy isoflavone, exerts antidepressant-like effects in mice: Involvement of serotonergic system

Genistein, a principal isoflavone property of soybeans, possesses multiple pharmacological activities such as neuroprotection. Recently, it was reported that genistein exerted antidepressant-like effects in animal models, but the mechanism of action remains ambiguous. The purpose of this study was to investigate the antidepressant-like effect of genistein in mice and explore the underlying mechanism(s), using two mouse models of depression, i.e. forced swim test (FST) and tail suspension test (TST). Chronic, but not acute (single dose), genistein treatment (5, 15 or 45 mg/kg, p.o., once per day for three weeks) exerted dose-dependently antidepressant-like effect in mice, concomitant with escalated levels of brain monoamines and suppressed monoamine oxidase (MAO) activity. Chemical depletion of brain serotonin by PCPA abrogated the antidepressant-like action of genistein, but it was not the case for ablation of NA by DSP-4. Moreover, the anti-depression by genistein was preferentially counteracted by co-administration of 5-HT_1A receptor antagonist WAY-100635, suggesting a pivotal role for 5-HT system coupled with 5-HT_1A receptors in mediating such genistein anti-depression. This point was further validated by the fact that genistein action was potentiated by co-treatment with 8-OH-DPAT, a selective 5-HT_1A receptor agonist. Collectively, these findings confirm that chronic genistein administration to mice engenders antidepressant-like efficacy evidenced by lessened behavioral despair. Serotonergic system that preferentially couples with 5-HT_1A receptors may be critically responsible for the present genistein anti-depression.

Acute stress regulates phosphorylation of N-methyl-d-aspartate receptor GluN2B at S1284 in hippocampus

Exposure to acute stress leads to diverse changes, which include either beneficial or deleterious effects on molecular levels that are implicated in stress-related disorders. N-methyl-d-aspartate receptor (NMDAR)-mediated signalings, are thought to be vital players in stress-related mental disorders as well as attractive therapeutic targets for clinical treatment. In the present study, we utilized acute stress models in mice to explore regulation of phosphorylation level of S1284 in GluN2B subunit of NMDAR. We found out that forced swimming and acute restraint stress increased phosphorylation level of S1284, while phosphorylation level of S1284 was unaltered after brief exposure to open field. Moreover, phosphorylation change of S1284 was negated by treatment of roscovitine which is believed to be a Cyclin-dependent kinase inhibitor. Besides, we showed well correlation of phosphorylation change of S1284 and immobility time during forced swimming. Collectively, our results demonstrated that phosphorylation level of S1284 in GluN2B was regulated by acute stress.

5,7-Dimethoxycoumarin prevents chronic mild stress induced depression in rats through increase in the expression of heat shock protein-70 and inhibition of monoamine oxidase-A levels

The current study was aimed to investigate the role of 5,7-dimethoxycoumarin in the prevention of chronic mild stress induced depression in rats. The chronic mild stress rat model was prepared using the known protocols. The results from open-field test showed that rats in the chronic mild stress group scored very low in terms of crossings and rearings than those of the normal rats. However, pre-treatment of the rats with 10 mg/kg doses of 5,7-dimethoxycoumarin prevented decline in the locomotor activity by chronic mild stress. The level of monoamine oxidase-A in the chronic mild stress rat hippocampus was markedly higher. Chronic mild stress induced increase in the monoamine oxidase-A level was inhibited by pre-treatment with 10 mg/kg doses of 5,7-dimethoxycoumarin in the rats. Chronic mild stress caused a marked increase in the level of caspase-3 mRNA and proteins in rat hippocampus tissues. The increased level of caspase-3 mRNA and protein level was inhibited by treatment of rats with 5,7-dimethoxycoumarin (10 mg/kg). 5,7-Dimethoxycoumarin administration into the rats caused a marked increase in the levels of heat shock protein-70 mRNA and protein. The levels of heat shock protein-70 were markedly lower both in normal and chronic mild stress groups of rats compared to the 5,7-dimethoxycoumarin treated groups. Thus 5,7-dimethoxycoumarin prevented the chronic mild stress induced depression in rats through an increase in the expression of heat shock protein-70 and inhibition of monoamine oxidase-A levels.

Natural and synthetic bioactive inhibitors of glycogen synthase kinase

Glycogen synthase kinase-3 is a multi-functional serine-threonine kinase and is involved in diverse physiological processes, including metabolism, cell cycle, and gene expression by regulating a wide variety of known substrates like glycogen synthase, tau-protein and β-catenin. Aberrant GSK-3 has been involved in diabetes, inflammation, cancer, Alzheimer's and bipolar disorder. In this review, we present an overview of the involvement of GSK-3 in various signalling pathways, resulting in a number of adverse pathologies due to its dysregulation. In addition, a detailed description of the small molecule inhibitors of GSK-3 with different mode of action discovered or specifically developed for GSK-3 has been presented. Furthermore, some clues for the future optimization of these promising molecules to develop specific drugs inhibiting GSK-3, for the treatment of associated disease conditions have also been discussed.

Animal models of depression: molecular perspectives

Much of the current understanding about the pathogenesis of altered mood, impaired concentration and neurovegetative symptoms in major depression has come from animal models. However, because of the unique and complex features of human depression, the generation of valid and insightful depression models has been less straightforward than modeling other disabling diseases like cancer or autoimmune conditions. Today's popular depression models creatively merge ethologically valid behavioral assays with the latest technological advances in molecular biology and automated video-tracking. This chapter reviews depression assays involving acute stress (e.g., forced swim test), models consisting of prolonged physical or social stress (e.g., social defeat), models of secondary depression, genetic models, and experiments designed to elucidate the mechanisms of antidepressant action. These paradigms are critically evaluated in relation to their ease, validity and replicability, the molecular insights that they have provided, and their capacity to offer the next generation of therapeutics for depression.

Reproductive Neuroendocrine Pathways of Social Behavior

Social behaviors are key components of reproduction, because they are essential for successful fertilization. Social behaviors, such as courtship, mating, and aggression, are strongly associated with sex steroids, such as testosterone, estradiol, and progesterone. Secretion of sex steroids from the gonads is regulated by the hypothalamus-pituitary-gonadal (HPG) axis in vertebrates. Gonadotropin-releasing hormone (GnRH) is a pivotal hypothalamic neuropeptide that stimulates gonadotropin release from the pituitary. In recent years, the role of neuropeptides containing the C-terminal Arg-Phe-NH2 (RFamide peptides) has been emphasized in vertebrate reproduction. In particular, two key RFamide peptides, kisspeptin and gonadotropin-inhibitory hormone (GnIH), emerged as critical accelerator and suppressor of gonadotropin secretion. Kisspeptin stimulates GnRH release by directly acting on GnRH neurons, whereas GnIH inhibits gonadotropin release by inhibiting kisspeptin, GnRH neurons, or pituitary gonadotropes. These neuropeptides can regulate social behavior by regulating the HPG axis. However, distribution of neuronal fibers of GnRH, kisspeptin, and GnIH neurons is not limited within the hypothalamus, and the existence of extrahypothalamic neuronal fibers suggests direct control of social behavior within the brain. It has traditionally been shown that central administration of GnRH can stimulate female sexual behavior in rats. Recently, it was shown that Kiss1, one of the paralogs of kisspeptin peptide family, regulates fear responses in zebrafish and GnIH inhibits sociosexual behavior in birds. Here, we highlight recent findings regarding the role of GnRH, kisspeptin, and GnIH in the regulation of social behaviors in fish, birds, and mammals and discuss their importance in future biological and biomedical research.

Neuronal correlates of depression

Major depressive disorder (MDD) is a common psychiatric disorder effecting approximately 121 million people worldwide and recent reports from the World Health Organization (WHO) suggest that it will be the leading contributor to the global burden of diseases. At present, the most commonly used treatment strategies are still based on the monoamine hypothesis that has been the predominant theory in the last 60 years. Clinical observations show that only a subset of depressed patients exhibits full remission when treated with classical monoamine-based antidepressants together with the fact that patients exhibit multiple symptoms suggest that the pathophysiology leading to mood disorders may differ between patients. Accumulating evidence indicates that depression is a neural circuit disorder and that onset of depression may be located at different regions of the brain involving different transmitter systems and molecular mechanisms. This review synthesises findings from rodent studies from which emerges a role for different, yet interconnected, molecular systems and associated neural circuits to the aetiology of depression.

The combination of agomelatine and ritanserin exerts a synergistic interaction in passive avoidance task

Agomelatine is a potent agonist at melatonergic 1 and 2 (MT1 and MT2) receptors and an antagonist at serotonin-2C (5HT-2C) receptors. It was suggested that psychotropic effects of agomelatine is associated with its melatonergic and serotonergic effects. In this study, we aimed to evaluate the effects of agomelatine alone or in combination with ritanserin (5HT-2A/2C antagonist) on memory and learning. Male Balb-C mice (25–30 g) were used, and all drugs and saline were administrated by intraperitoneal (i.p.) route 30 min prior to evaluating retention time. Whilst agomelatine was administered at the doses of 1, 10 and 30 mg/kg, ritanserin was administered at the doses of 0.1, 1 and 10 mg/kg. To evaluate memory function, passive avoidance test was used. On the first day, acquisition time and on the second day (after 24h), retention time of mice were recorded. To evaluate the synergistic activity, only the least doses of agomelatine and ritanserine were used, that is, 1 and 0.1 mg/kg, respectively. Scopolamine (1 mg/kg) was used as a reference drug, so it was combined with drug groups. Our results show that 5HT-2A/2C receptor antagonist ritanserin (1 and 4 mg/kg, i.p.) and agomelatine (10 and 30 mg/kg, i.p.) improve memory deficit induced by scopolamine, whilst a synergistic interaction is observed between ritanserin and agomelatine (0.1 mg/kg and 1 mg/kg, i.p., respectively) when they were administered at their ineffective doses. According to our findings, we concluded that agomelatine improves memory deficit and thus improves the effect of agomelatine arises from its 5HT-2C receptor antagonist activity.

Quetiapine and repetitive transcranial magnetic stimulation ameliorate depression-like behaviors and up-regulate the proliferation of hippocampal-derived neural stem cells in a rat model of depression: The involvement of the BDNF/ERK signal pathway

Quetiapine (QUE) and repetitive transcranial magnetic stimulation (rTMS) have been considered to be possible monotherapies for depression or adjunctive therapies for the treatment of the resistant depression, but the underlying mechanisms remain unclear. The present study aimed to assess the effects of combined QUE and rTMS treatment on depressive-like behaviors, hippocampal proliferation, and the in vivo and in vitro expressions of phosphorylated extracellular signal-regulated protein kinase (pERK1/2) and brain-derived neurotrophic factor (BDNF) in male Sprague-Dawley rats. The administration of QUE and rTMS was determined not only to reverse the depressive-like behaviors of rats exposed to chronic unpredictable stress (CUS) but also to restore the protein expressions of pERK1/2 and BDNF and cell proliferation in the hippocampus. Additionally, QUE and rTMS promoted the proliferation and increased the expression of pERK1/2 and BDNF in hippocampal-derived neural stem cells (NSCs), and these effects were abolished by U0126. Taken together, these results suggest that the antidepressive-like effects of QUE and rTMS might be related to the activation of the BDNF/ERK signaling pathway and the up-regulation of cell proliferation in the hippocampus.

Neurotransmitter Systems in a Mild Blast Traumatic Brain Injury Model: Catecholamines and Serotonin

Exposure to improvised explosive devices can result in a unique form of traumatic brain injury--blast-induced traumatic brain injury (bTBI). At the mild end of the spectrum (mild bTBI [mbTBI]), there are cognitive and mood disturbances. Similar symptoms have been observed in post-traumatic stress disorder caused by exposure to extreme psychological stress without physical injury. A role of the monoaminergic system in mood regulation and stress is well established but its involvement in mbTBI is not well understood. To address this gap, we used a rodent model of mbTBI and detected a decrease in immobility behavior in the forced swim test at 1 d post-exposure, coupled with an increase in climbing behavior, but not after 14 d or later, possibly indicating a transient increase in anxiety-like behavior. Using in situ hybridization, we found elevated messenger ribonucleic acid levels of both tyrosine hydroxylase and tryptophan hydroxylase 2 in the locus coeruleus and the dorsal raphe nucleus, respectively, as early as 2 h post-exposure. High-performance liquid chromatography analysis 1 d post-exposure primarily showed elevated noradrenaline levels in several forebrain regions. Taken together, we report that exposure to mild blast results in transient changes in both anxiety-like behavior and brain region-specific molecular changes, implicating the monoaminergic system in the pathobiology of mbTBI.

Pioglitazone adjunctive therapy for depressive episode of bipolar disorder: a randomized, double-blind, placebo-controlled trial

BACKGROUND

The antidepressive effect of pioglitazone has been noted in patients with major depressive disorder in absence of metabolic syndrome. This study was conducted to evaluate the safety and efficacy of pioglitazone in patients with bipolar depression without concomitant metabolic syndrome or diabetes.

METHOD

Forty-eight outpatients with the diagnosis of bipolar I disorder and a major depressive episode participated in a parallel, randomized, double-blind, placebo-controlled trial, and 44 patients underwent 6-week treatment with either pioglitazone (30 mg/day) or placebo as an adjunctive treatment to lithium. Therapeutic serum lithium levels of 0.6-0.8 mEq/L were required for two or more consecutive weeks immediately before starting pioglitazone and during the 6-week study. Patients were evaluated using Hamilton Depression Rating Scale (HDRS) and Young Mania Rating Scale (YMRS) at baseline and weeks 1, 2, 4, and 6. The primary outcome was to evaluate the efficacy of pioglitazone in improving the depressive symptoms.

RESULT

General linear model repeated measures showed significant effect for time × treatment interaction on the HDRS scores [F(2.78, 116.65) = 4.77, P = .005]. Significantly greater reduction was observed in HDRS scores in the pioglitazone group than the placebo group from baseline HDRS score at weeks 2, 4, and 6, P = .003, .006, and .006, respectively. No serious adverse event was observed.

CONCLUSION

This study showed that pioglitazone could be a tolerable and effective adjunctive therapy for improving depressive symptoms in bipolar disorder without type 2 diabetes or metabolic syndrome.

The effects of GSK-3β blockade on ketamine self-administration and relapse to drug-seeking behavior in rats

RATIONALE

The role of glycogen synthase kinase-3 (GSK-3) has recently been implicated in the neurochemical mechanism underlying ketamine-induced neuronal toxicity and behavioral disturbance.

OBJECTIVES

The primary goal of the present study was to determine the role of GSK-3β in ketamine self-administration (SA) and relapse to drug-seeking behavior after abstinence.

METHODS

In Experiment 1, the level of phosphorylated GSK-3β (p-GSK-3β) and total GSK-3β (t-GSK-3β) was determined in various brain areas following 14 days of ketamine SA. In Experiments 2 and 3, the effects of a GSK-3β inhibitor, SB216763 (2 and 4 mg/kg) and a GSK-3 inhibitor, lithium (LiCl, 100mg/kg) on the responding maintained by 0.5mg/kg/infusion ketamine SA were evaluated. In Experiments 4 and 5, rats underwent ketamine SA for 14 days followed by a 10-day abstinence period. The animals were treated with 2 or 4 mg/kg GSK-3β inhibitor, or 100mg/kg LiCl during the cue-induced relapse test. Seven days later, animals received the same drug treatment and underwent the drug-induced relapse test. Finally, the effect of saline and DMSO on locomotor activity was evaluated in Experiment 6.

RESULTS

Ketamine SA significantly decreased the ratio p-GSK-3β and t-GSK-3β (p-GSK-3β:t-GSK-3β) in the caudate putamen, nucleus accumbens, and ventral tegmental area. Both SB216763 and LiCl decreased responding on a progressive ratio schedule, but not on a fixed ratio schedule. Cue-induced relapse was suppressed only by 4mg/kg SB216763, whereas drug-induced relapse was inhibited by 2, 4 mg/kg SB216763 and LiCl. However, inactive responses were also suppressed by LiCl during progressive ratio and drug-induced relapse testing.

CONCLUSIONS

SB216763 was effective at decreasing ketamine SA under the PR schedule and reducing drug-seeking behavior after abstinence.