Antidepressant-induced Dopamine Receptor Dysregulation: A Valid Animal Model of Manic-Depressive Illness

Doxycycline reversal of amphetamine-induced mania-like behavior is related to adjusting brain monoamine abnormalities and antioxidant effects in primary hippocampal neurons

Mania is associated with disturbed dopaminergic transmission in frontotemporal regions. D-amphetamine (AMPH) causes increased extracellular DA levels, considered an acknowledged mania model in rodents. Doxycycline (DOXY) is a second-generation tetracycline with promising neuroprotective properties. Here, we tested the hypothesis that DOXY alone or combined with Lithium (Li) could reverse AMPH-induced mania-like behavioral alterations in mice by the modulation of monoamine levels in brain areas related to mood regulation, as well as cytoprotective and antioxidant effects in hippocampal neurons. Male Swiss mice received AMPH or saline intraperitoneal (IP) injections for 14 days. Between days 8-14, mice receive further IP doses of DOXY, Li, or their combination. For in vitro studies, we exposed hippocampal neurons to DOXY in the presence or absence of AMPH. DOXY alone or combined with Li reversed AMPH-induced risk-taking behavior and hyperlocomotion. DOXY also reversed AMPH-induced hippocampal and striatal hyperdopaminergia. In AMPH-exposed hippocampal neurons, DOXY alone and combined with Li presented cytoprotective and antioxidant effects, while DOXY+Li also increased the expression of phospho-Ser133-CREB. Our results add novel evidence for DOXY's ability to reverse mania-like features while revealing that antidopaminergic activity in some brain areas, such as the hippocampus and striatum, as well as hippocampal cytoprotective effects may account for this drug's antimanic action. This study provides additional rationale for designing clinical trials investigating its potential as a mood stabilizer agent.

[Bipolar affective disorder occurring with psychopharmacotherapy-induced manic phases]

To analyze the stages of development of the problem, identify the evolution of views and the main directions of current research in the field of bipolar affective disorder, which occurs with psychopharmacotherapy-induced manic phases, the search for publications by keywords «pharmaco-induced mania»", «bipolar affective disorder» was carried out in the PubMed/MEDLINE, Russian Citation index and other sources from the mid-19th century to the present. The issue of adequate treatment of bipolar depression became relevant back in the 20th century; numerous observations indicated the presence of associated risks when using antidepressants in patients with bipolar affective disorder, namely, the likelihood of affect inversion and aggravation of the course of the disease (accelerated cyclicity, continuum). In recent years, due to the expansion of research capabilities and the introduction of biological psychiatry, works have appeared that consider this problem from both clinical and pharmacodynamic, genetic and neurophysiological aspects, which opens up the prospect of developing advanced methods of personalized medicine for the diagnosis and treatment of bipolar disorder, taking into account the need to minimize iatrogenic effects.

D1R-5-HT2AR Uncoupling Reduces Depressive Behaviours via HDAC Signalling

Dopamine and serotonin signalling are associated with major depressive disorder, which is a prevalent life-threatening illness worldwide. Numerous FDA-approved dopamine/serotonin signalling-modifying drugs are available but are associated with concurrent side effects and limited efficacy. Thus, identifying and targeting their signalling pathway is crucial for improving depression treatment. Here, we determined that serotonin receptor 2A (5-HT2AR) abundantly forms a protein complex with dopamine receptor 1 (D1R) in high abundance via its carboxy-terminus in the brains of mice subjected to various chronic stress paradigms. Furthermore, the D1R/5-HT2AR interaction elicited CREB/ERK/AKT modulation during synaptic regulation. An interfering peptide (TAT-5-HT2AR-SV) agitated the D1R/5-HT2AR interaction and attenuated depressive symptoms accompanied by CREB/ERK molecule costimulation. Interestingly, HDAC antagonism but not TrkB antagonism reversed the antidepressant effect of competitive peptides. These findings revealed a novel D1R/5-HT2AR heteroreceptor complex mechanism in the pathophysiology of depression, and their uncoupling ameliorates depressive-like behaviours through HDAC-, and not BDNF-, dependent mechanisms.

Antidepressant emergent mood switch in major depressive disorder: onset, clinical correlates and impact on suicidality

Antidepressant (AD)- emergent mood switch (AEMS) is a common complication of bipolar depression. This study aimed to investigate the prevalence and clinical correlates of subthreshold AEMS (i.e. not fulfilling DSM criteria for hypomanic episodes) in major depressive disorder (MDD) and, prognostically, its impact on AD treatment outcome and suicidality. The study involved 425 outpatients with MDD followed during the acute phase (12 weeks) and continuation (weeks 13-28) AD treatment. AEMS was assessed through the Altman Self-Rating Mania scale (ASRM ≥ 6). Several clinical features differentiated individuals with or without subthreshold AEMS (n = 204 vs. 221): negative self-perception [odds ratio (OR) 1.017-1.565]; panic disorder (OR 1.000-1.091); subthreshold hypomanic episodes (OR 1.466-13.352); childhood emotional abuse (OR 1.053-2.447); lifetime suicidal behaviour (OR 1.027-1.236); AD-related remission (χ 2  = 22.903 P  < 0.0001) and suicide ideation (χ 2  = 16.701 P  < 0.0001). In AEMS earlier onset showed a strong correlation with bipolar spectrum disorder (overall score: P  = 0.0053; mixed depression: P  = 0.0154; subthreshold hypomania: P  = 0.0150) whereas late-onset was associated with more severe suicidal behaviour ( P  < 0.001). In conclusion, our results demonstrate that subthreshold mood switches occur frequently in unipolar depression during acute AD treatment as well as in continuation phase. Time of switch onset seems to have the greatest diagnostic and prognostic value.

Validation of the Thyrotoxicosis-associated Insomnia Model Induced by Thyroxine through Sympathetic Stimulation: Face, Construct and Predictive Perspectives

Insomnia has become a common central nervous system disease. At present, the pathogenesis of insomnia is not clear. Animal models can help us understand the pathogenesis of the disease and can be used in transformational medicine. Therefore, it is very necessary to establish an appropriate model of insomnia. Clinical data show that insomnia patients with high levels of thyroxine and often accompanied by cardiovascular problems, a common mechanism underlying all of these physiological disruptions is the sympathetic nervous system. Combined with the characteristics of chronic onset of clinical insomnia, an insomnia model induced by long-term intraperitoneal injection of thyroid hormone has been created in our laboratory. In this paper, the insomnia-like state of the model was evaluated based on three validity criteria. Face validity has been demonstrated in metabolism, the Morris water maze, electrocardiogram (ECG) and electroencephalogram (EEG). Structure validity has been proved by the results of targeted metabolomics. After treatment with diazepam, a commonly used clinical anti-insomnia drug, the above physiological and pathological disorders were reversed. The results of comprehensive analysis show that the established thyrotoxicosis-associated insomnia model meets the validity requirement to establish an appropriate animal model of insomnia. The model presented in this article might help to study pathogenetic mechanisms of clinical insomnia, as well as to test promising methods of insomnia treatment.

Therapeutic Effect of Novel Antidepressant Drugs Acting at Specific Receptors of Neurotransmitters and Neuropeptides

BACKGROUND

Major depression is a frequent psychiatric disease. One- third of the depressive patients remain treatment-resistant; thus, it is urgent to find novel antidepressant drugs.

OBJECTIVE

In major depression, in several brain areas the neural networks involved and the alterations of neurotransmitters and neuropeptides are updated. According to these networks, new pharmacological agents and effective combinations of antidepressant drugs achieving a more efficacious antidepressant treatment are suggested.

RESULTS

In the neural networks, the prefrontal cortex has been included. In this brain area, glutamatergic neurons, which receive an activating potential from D2 dopaminergic neurons, presynaptically inhibit M1 muscarinic cholinergic neurons via NMDA receptors. Medium spiny GABAergic/somatostatin neurons, which receive projections from M1 muscarinic cholinergic neurons, presynaptically inhibit D2 dopaminergic neurons via GABAA/somatostatin1 receptors. The combination of an NMDA receptor antagonist with an M1 muscarinic cholinergic receptor antagonist can achive a rapid, long-lasting antidepressant effect.

CONCLUSION

In preclinical studies, the antidepressant effect of orvepitant, an NK1 receptor antagonist, has been demonstrated: this antagonist reaches a complete blockade of NK1 receptors. In clinical studies, the combination of an NMDA receptor antagonist with an M1 muscarinic cholinergic receptor antagonist should be investigated indepth as well as the therapeutic effect of orvepitant. In clinical studies, the antidepressant effect of a triple reuptake inhibitor should be examined and compared to current antidepressant drugs.

Agitated depression in bipolar disorder

OBJECTIVES

It has been suggested that agitated depression (AD) is a common, severe feature in bipolar disorder. We aimed to estimate the prevalence of AD and investigate whether presence of AD was associated with episodic and lifetime clinical features in a large well-characterized bipolar disorder sample.

METHOD

The prevalence of agitation, based on semi-structured interview and medical case-notes, in the most severe depressive episode was estimated in 2925 individuals with DSM-IV bipolar disorder recruited into the UK Bipolar Disorder Research Network. Predictors of agitation were ascertained using symptoms within the same episode and lifetime clinical features using multivariate models.

RESULTS

32.3% (n = 946) experienced agitation during the worst depressive episode. Within the same episode, significant predictors of presence of agitation were: insomnia (OR 2.119, P < 0.001), poor concentration (OR 1.966, P = 0.027), decreased libido (OR 1.960, P < 0.001), suicidal ideation (OR 1.861, P < 0.001), slowed activity (OR 1.504, P = 0.001), and poor appetite (OR 1.297, P = 0.029). Over the lifetime illness course, co-morbid panic disorder (OR 2.000, P < 0.001), suicide attempt (OR 1.399, P = 0.007), and dysphoric mania (OR 1.354, P = 0.017) were significantly associated with AD.

CONCLUSIONS

Agitation accompanied bipolar depression in at least one-third of cases in our sample and was associated with concurrent somatic depressive symptoms, which are also common features of mixed manic states. Furthermore, AD in our sample was associated with lifetime experience of mixed mania, in addition to severe lifetime illness course including comorbid panic disorder and suicidal behavior. Our results have implications for the diagnosis and treatment of agitated features in bipolar depression.