A novel murine model of mania.

Neuropathological mechanisms of manic syndrome or manic episodes in bipolar disorder remain poorly characterised, as the research progress is severely limited by the paucity of appropriate animal models. Here we developed a novel mania mice model by combining a series of chronic unpredictable rhythm disturbances (CURD), which include disruption of circadian rhythm, sleep deprivation, exposure to cone light, with subsequent interference of followed spotlight, stroboscopic illumination, high-temperature stress, noise disturbance and foot shock. Multiple behavioural and cell biology tests comparing the CURD-model with healthy controls and depressed mice were deployed to validate the model. The manic mice were also tested for the pharmacological effects of various medicinal agents used for treating mania. Finally, we compared plasma indicators of the CURD-model mice and the patients with the manic syndrome. The CURD protocol produced a phenotype replicating manic syndrome. Mice exposed to CURD presented manic behaviours similar to that observed in the amphetamine manic model. These behaviours were distinct from depressive-like behaviours recorded in mice treated with a depression-inducing protocol of chronic unpredictable mild restraint (CUMR). Functional and molecular indicators in the CURD mania model showed multiple similarities with patients with manic syndrome. Treatment with LiCl and valproic acid resulted in behavioural improvements and recovery of molecular indicators. A novel manic mice model induced by environmental stressors and free from genetic or pharmacological interventions is a valuable tool for research into pathological mechanisms of mania.

Leptin Attenuates Fear Memory by Inhibiting Astrocytic NLRP3 Inflammasome in Post-traumatic Stress Disorder Model.

Accumulating evidence suggests that the activation of nucleotide-binding domain and leucine-rich repeat protein-3 (NLRP3) inflammasome contributes to the pathophysiology of post-traumatic stress disorder (PTSD). Astrocytes, the homeostatic cells of the central nervous system are intimately involved into pathophysiology of various mental disorders including PTSD. We demonstrated previously that leptin exerts neuroprotection and ameliorates chronic sleep deprivation-induced depressive-like behaviours. Here, we extended the study of therapeutic effects of leptin to PTSD model mice. We discovered that PTSD is associated with significant activation of NLRP3 inflammasome in astrocytes sorted from GFAP-GFP transgenic mice, while administration of leptin markedly suppressed the activation of astrocytic NLRP3 inflammasome. Leptin effectively improved PTSD-associated behavioural alterations including fear memory, cognitive impairments, and depressive-like behaviours. Therapeutic effects of leptin were mediated by the signal transducer and activator of transcription 3 (STAT3) in astrocytes. In addition, the PTSD-related activation of NLRP3 inflammasome impairs astrocytic mitochondria suppressing ATP synthesis and leading to an increased ROS production. Leptin reversed mitochondrial inhibition by stimulating STAT3 in astrocytes. We propose leptin as a novel candidate for the pharmacological treatment of PTSD.

The Association Between Antidepressant Effect of SSRIs and Astrocytes: Conceptual Overview and Meta-analysis of the Literature.

Major depressive disorders (MDD) a worldwide psychiatric disease, is yet to be adequately controlled by therapies; while the mechanisms of action of antidepressants are yet to be fully characterised. In the last two decades, an increasing number of studies have demonstrated the role of astrocytes in the pathophysiology and therapy of MDD. Selective serotonin reuptake inhibitors (SSRIs) are the most widely used antidepressants. It is generally acknowledged that SSRIs increase serotonin levels in the central nervous system by inhibiting serotonin transporters, although the SSRIs action is not ideal. The SSRIs antidepressant effect develops with considerable delay; their efficacy is low and frequent relapses are common. Neither cellular nor molecular pharmacological mechanisms of SSRIs are fully characterised; in particular their action on astrocytes remain underappreciated. In this paper we overview potential therapeutic mechanisms of SSRIs associated with astroglia and report the results of meta-analysis of studies dedicated to MDD, SSRIs and astrocytes. In particular, we argue that fluoxetine, the representative SSRI, improves depressive-like behaviours in animals treated with chronic mild stress and reverses depression-associated decrease in astrocytic glial fibrillary acidic protein (GFAP) expression. In addition, fluoxetine upregulates astrocytic mRNA expression of 5-hydroxytriptamin/serotonin2B receptors (5-HT2BR). In summary, we infer that SSRIs exert their anti-depressant effect by regulating several molecular and signalling pathways in astrocytes.

Regulation of Glycogen Content in Astrocytes via Cav-1/PTEN/AKT/GSK-3ß Pathway by Three Anti-bipolar Drugs.

Here we present the data indicating that chronic treatment with three antibipolar drugs, lithium, carbamazepine and valproic acid regulates Cav-1/PTEN/PI3K/AKT/GSK-3ß signalling pathway and glycogen content in primary cultured astrocytes. All three drugs down-regulate gene expression of Caveoline 1 (Cav-1), decrease membrane content of phosphatase and tensin homolog (PTEN), increase activity of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) and serine-threonine kinase (AKT), and elevate glycogen synthase kinase 3ß (GSK-3ß) phosphorylation thus suppressing its activity. As expected, treatment with any of these three drugs increases glycogen content in astrocytes. Our findings indicate that regulation of glycogen content via Cav-1/PTEN/AKT/GSK-3ß pathway by the three anti-bipoar drugs may be responsible for therapeutic effects of these drugs, and Cav-1 is an important signal element that may contribute to pathogenesis of various CNS diseases and regulation of its gene expression may be one of the underlying mechanisms of drug action for antibipolar drugs and antidepressants currently in clinical use.

Lithium Inhibits GSK3ß Activity via Two Different Signaling Pathways in Neurons After Spinal Cord Injury.

Spinal cord injury (SCI) is a type of long-term disability with a high morbidity rate in clinical settings for which there is no effective clinical treatment to date. Usually, lithium is used as a popular mood stabilizer. Recently, growing evidence has shown that lithium has clear neuroprotective effects after SCI, and the administration of lithium can effectively improve locomotor recovery. However, the exact neuroprotective mechanism of lithium is still not understood. Glycogen synthase kinase-3 beta (GSK3ß) is a serine/threonine kinase that plays an important role in the neuroprotective effects of lithium both in vivo and in vitro. In this study, we discovered that lithium inhibits GSK3ß activity through two different signaling pathways in spinal cord neurons. In the acute phase, lithium inhibited GSK3ß activity by stimulating phosphorylation of AKT; in the chronic phase, we first discovered that lithium additionally upregulated the expression of Na+, K+-ATPase α1 (NKA α1), which had an inhibitory effect on GSK3ß activity by inducing the expression of glucocorticoid inducible kinase 1 (SGK1). SGK1 is well known as a regulator of the GSK3ß/ß-catenin signaling pathway. Moreover, the suppressed activity of GSK3ß increased the level of ß-catenin in the cytoplasm, which gave rise to the translocation of the freely stabilized ß-catenin to the nucleus. In addition, the accumulation of ß-catenin in the nucleus had the benefits of neuronal survival. Hopefully our findings from this study are beneficial in revealing the neuroprotective mechanism of lithium and in offering novel targets for the development of new SCI therapeutic drugs.

The ameliorative effect of fluoxetine on neuroinflammation induced by sleep deprivation.

It is well known that sleep disorders are harmful to people's health and performance, and growing evidence suggests that sleep deprivation (SD) can trigger neuroinflammation in the brain. The nucleotide-binding domain and leucine-rich repeat protein-3 (NLRP3) inflammasome is reported to be relevant to the neuroinflammation induced by SD, but the regulatory signaling that governs the NLRP3 inflammasome in SD is still unknown. Meanwhile, whether the regulatory action of antidepressants in astrocytes could affect the neuroinflammation induced by SD also remains obscure. In this study, we were the first to discover that the antidepressant fluoxetine, a type of specific serotonin reuptake inhibitor widely used in clinical practice, could suppress the neuroinflammation and neuronal apoptosis induced by SD. The main findings from this study are as follows: (i) SD stimulated the expression of activated NLRP3 inflammasomes and the maturation of IL-1ß/18 via suppressing the phosphorylation of STAT3 in astrocytes; (ii) SD decreased the activation of AKT and stimulated the phosphorylation of GSK-3ß, which inhibited the phosphorylation of STAT3; (iii) the NLRP3 inflammasome expression stimulated by SD was partly mediated by the P2X7 receptor; (iv) an agonist of STAT3 could significantly abolish the expression of NLRP3 inflammasomes induced by an agonist of the P2X7 receptor in primary cultured astrocytes; (v) the administration of fluoxetine could reverse the stimulation of NLRP3 inflammasome expression and function by SD through elevating the activation of STAT3. In conclusion, our present research suggests the promising possibility that fluoxetine could ameliorate the neuronal impairment induced by SD.

Suppression of glymphatic fluid transport in a mouse model of Alzheimer's disease.

Glymphatic transport, defined as cerebrospinal fluid (CSF) peri-arterial inflow into brain, and interstitial fluid (ISF) clearance, is reduced in the aging brain. However, it is unclear whether glymphatic transport affects the distribution of soluble Aß in Alzheimer's disease (AD). In wild type mice, we show that Aß40 (fluorescently labeled Aß40 or unlabeled Aß40), was distributed from CSF to brain, via the peri-arterial space, and associated with neurons. In contrast, Aß42 was mostly restricted to the peri-arterial space due mainly to its greater propensity to oligomerize when compared to Aß40. Interestingly, pretreatment with Aß40 in the CSF, but not Aß42, reduced CSF transport into brain. In APP/PS1 mice, a model of AD, with and without extensive amyloid-ß deposits, glymphatic transport was reduced, due to the accumulation of toxic Aß species, such as soluble oligomers. CSF-derived Aß40 co-localizes with existing endogenous vascular and parenchymal amyloid-ß plaques, and thus, may contribute to the progression of both cerebral amyloid angiopathy and parenchymal Aß accumulation. Importantly, glymphatic failure preceded significant amyloid-ß deposits, and thus, may be an early biomarker of AD. By extension, restoring glymphatic inflow and ISF clearance are potential therapeutic targets to slow the onset and progression of AD.

Leptin suppresses adenosine triphosphate-induced impairment of spinal cord astrocytes.

Spinal cord injury (SCI) causes long-term disability and has no clinically effective treatment. After SCI, adenosine triphosphate (ATP) may be released from neuronal cells and astrocytes in large amounts. Our previous studies have shown that the extracellular release of ATP increases the phosphorylation of cytosolic phospholipase A2 (cPLA2 ) and triggers the rapid release of arachidonic acid (AA) and prostaglandin E2 (PGE2) via the stimulation of epidermal growth factor receptor (EGFR) and the downstream phosphorylation of extracellular-regulated protein kinases 1 and 2. Leptin, a glycoprotein, induces the activation of the Janus kinase (JAK2)/signal transducers and activators of transcription-3 (Stat3) pathway via the leptin receptor. In this study, we found that 1) prolonged leptin treatment suppressed the ATP-stimulated release of AA and PGE2 from cultured spinal cord astrocytes; 2) leptin elevated the expression of caveolin-1 (Cav-1) via the JAK2/Stat3 signaling pathway; 3) Cav-1 blocked the interaction between Src and EGFR, thereby inhibiting the phosphorylation of EGFR and cPLA2 and attenuating the release of AA or PGE2; 4) pretreatment with leptin decreased ;he level of apoptosis and the release of interleukin-6 from cocultured neurons and astrocytes; and 5) leptin improved the recovery of locomotion in mice after SCI. Our results highlight leptin as a promising therapeutic agent for SCI. © 2016 Wiley Periodicals, Inc.

Neuronal transgene expression in dominant-negative SNARE mice.

Experimental advances in the study of neuroglia signaling have been greatly accelerated by the generation of transgenic mouse models. In particular, an elegant manipulation that interferes with astrocyte vesicular release of gliotransmitters via overexpression of a dominant-negative domain of vesicular SNARE (dnSNARE) has led to documented astrocytic involvement in processes that were traditionally considered strictly neuronal, including the sleep-wake cycle, LTP, cognition, cortical slow waves, depression, and pain. A key premise leading to these conclusions was that expression of the dnSNARE was specific to astrocytes. Inconsistent with this premise, we report here widespread expression of the dnSNARE transgene in cortical neurons. We further demonstrate that the activity of cortical neurons is reversibly suppressed in dnSNARE mice. These findings highlight the need for independent validation of astrocytic functions identified in dnSNARE mice and thus question critical evidence that astrocytes contribute to neurotransmission through SNARE-dependent vesicular release of gliotransmitters.

Astrocytic glycogenolysis: mechanisms and functions.

Until the demonstration little more than 20 years ago that glycogenolysis occurs during normal whisker stimulation glycogenolysis was regarded as a relatively uninteresting emergency procedure. Since then, a series of important astrocytic functions has been shown to be critically dependent on glycogenolytic activity to support the signaling mechanisms necessary for these functions to operate. This applies to glutamate formation and uptake and to release of ATP as a transmitter, stimulated by other transmitters or elevated K(+) concentrations and affecting not only other astrocytes but also most other brain cells. It is also relevant for astrocytic K(+) uptake both during the period when the extracellular K(+) concentration is still elevated after neuronal excitation, and capable of stimulating glycogenolytic activity, and during the subsequent undershoot after intense neuronal activity, when glycogenolysis may be stimulated by noradrenaline. Both elevated K(+) concentrations and several transmitters, including the ß-adrenergic agonist isoproterenol and vasopressin increase free cytosolic Ca(2+) concentration in astrocytes, which stimulates phosphorylase kinase so that it activates the transformation of the inactive glycogen phosphorylase a to the active phosphorylase b. Contrary to common belief cyclic AMP plays at most a facilitatory role, and only when free cytosolic Ca(2+) concentration is also increased. Cyclic AMP is not increased during activation of glycogenolysis by either elevated K(+) concentrations or the stimulation of the serotonergic 5-HT(2B) receptor. Not all agents that stimulate glycogenolysis do so by directly activating phophorylase kinase--some do so by activating processes requiring glycogenolysis, e.g. for synthesis of glutamate.

Fluoxetine and all other SSRIs are 5-HT2B Agonists - Importance for their Therapeutic Effects.

Fluoxetine and other serotonin-specific re-uptake inhibitors (SSRIs) are generally thought to owe their therapeutic potency to inhibition of the serotonin transporter (SERT). However, research in our laboratory showed that it affects, with relatively high affinity the 5-HT2B receptor in cultured astrocytes; this finding was confirmed by independent observations showing that fluoxetine loses its ability to elicit SSRI-like responses in behavioral assays in mice in which the 5-HT2B receptor was knocked-out genetically or inhibited pharmacologically. All clinically used SSRIs are approximately equipotent towards 5-HT2B receptors and exert their effect on cultured astrocytes at concentrations similar to those used clinically, a substantial difference from their effect on SERT. We have demonstrated up-regulation and editing of astrocytic genes for ADAR2, the kainate receptor GluK2, cPLA2 and the 5-HT2B receptor itself after chronic treatment of cultures, which do not express SERT and after treatment of mice (expressing SERT) for 2 weeks with fluoxetine, followed by isolation of astrocytic and neuronal cell fractionation. Affected genes were identical in both experimental paradigms. Fluoxetine treatment also altered Ca(2+) homeostatic cascades, in a specific way that differs from that seen after treatment with the anti-bipolar drugs carbamazepine, lithium, or valproic acid. All changes occurred after a lag period similar to what is seen for fluoxetine's clinical effects, and some of the genes were altered in the opposite direction by mild chronic inescapable stress, known to cause anhedonia, a component of major depression. In the anhedonic mice these changes were reversed by treatment with SSRIs.

Trace metals and astrocytes physiology and pathophysiology.

Several trace metals, including iron, copper, manganese and zinc are essential for normal function of the nervous system. Both deficiency and excessive accumulation of these metals trigger neuropathological developments. The central nervous system (CNS) is in possession of dedicated homeostatic system that removes, accumulates, stores and releases these metals to fulfil nervous tissue demand. This system is mainly associated with astrocytes that act as dynamic reservoirs for trace metals, these being a part of a global system of CNS ionostasis. Here we overview physiological and pathophysiological aspects of astrocyte-cantered trace metals regulation.

Major depressive disorder: hypothesis, mechanism, prevention and treatment.

Worldwide, the incidence of major depressive disorder (MDD) is increasing annually, resulting in greater economic and social burdens. Moreover, the pathological mechanisms of MDD and the mechanisms underlying the effects of pharmacological treatments for MDD are complex and unclear, and additional diagnostic and therapeutic strategies for MDD still are needed. The currently widely accepted theories of MDD pathogenesis include the neurotransmitter and receptor hypothesis, hypothalamic-pituitary-adrenal (HPA) axis hypothesis, cytokine hypothesis, neuroplasticity hypothesis and systemic influence hypothesis, but these hypothesis cannot completely explain the pathological mechanism of MDD. Even it is still hard to adopt only one hypothesis to completely reveal the pathogenesis of MDD, thus in recent years, great progress has been made in elucidating the roles of multiple organ interactions in the pathogenesis MDD and identifying novel therapeutic approaches and multitarget modulatory strategies, further revealing the disease features of MDD. Furthermore, some newly discovered potential pharmacological targets and newly studied antidepressants have attracted widespread attention, some reagents have even been approved for clinical treatment and some novel therapeutic methods such as phototherapy and acupuncture have been discovered to have effective improvement for the depressive symptoms. In this work, we comprehensively summarize the latest research on the pathogenesis and diagnosis of MDD, preventive approaches and therapeutic medicines, as well as the related clinical trials.

Ketamine Improves the Glymphatic Pathway by Reducing the Pyroptosis of Hippocampal Astrocytes in the Chronic Unpredictable Mild Stress Model.

Ketamine as a glutamate receptor antagonist has a rapid, potent, and long-lasting antidepressant effect, but its specific mechanism is still not fully understood. Depression is associated with elevated levels of glutamate and astrocyte loss in the brain; the exploration of the relationships between ketamine's antidepressant effect and astrocytes has drawn great attention. Astrocytes and aquaporin 4 (AQP4) are essential components of the glymphatic system, which is a brain-wide perivascular pathway to help transport nutrients to the parenchyma and remove metabolic wastes. In this study, we investigated pyroptosis-associated protein Nlrp3/Caspase-1/Gsdmd-N expression in the hippocampus of mice and the toxic effect of high levels of glutamate on primary astrocytes. On this basis, the protective mechanism of ketamine is explored. A single administration of ketamine (10 mg/kg) remarkably relieved anxious and depressive behaviors in the sucrose preference test, elevated plus maze test, and forced swim test. Meanwhile, ketamine reduced the level of hippocampus Nlrp3 and the expression of its downstream molecules in chronic unpredictable mild stress (CUMS) mice model by western blot and reduced the colocalization of Gfap and Gsdmd by nearly 25% via immunofluorescent staining. Ketamine also increased the Gfap-positive cells and AQP4 expression in the hippocampus of the CUMS mice. More important, ketamine increased the distribution of the fluorescent tracer of CUMS mice. Treatment with 128 mM glutamate in cortical and hippocampus astrocytes increased the level of Nlrp3, and Gsdmd-N, and ketamine alleviated high glutamate-induced pyroptosis-associated proteins. In summary, these results suggest that high glutamate-induced astrocyte pyroptosis through the Nlrp3/Caspase-1/Gsdmd-N pathway which was inhibited by ketamine and ketamine can improve the damaged glymphatic function of the CUMS mice. The present study indicates that inhibiting astrocyte pyroptosis and promoting the glymphatic circulation function are a new mechanism of ketamine's antidepressant effect, and astrocyte pyroptosis may be a new target for other antidepressant medicines.

Dexmedetomidine improves the circulatory dysfunction of the glymphatic system induced by sevoflurane through the PI3K/AKT/ΔFosB/AQP4 pathway in young mice.

Multiple sevoflurane exposures may damage the developing brain. The neuroprotective function of dexmedetomidine has been widely confirmed in animal experiments and human studies. However, the effect of dexmedetomidine on the glymphatic system has not been clearly studied. We hypothesized that dexmedetomidine could alleviate sevoflurane-induced circulatory dysfunction of the glymphatic system in young mice. Six-day-old C57BL/6 mice were exposed to 3% sevoflurane for 2 h daily, continuously for 3 days. Intraperitoneal injection of either normal saline or dexmedetomidine was administered before every anaesthesia. Meanwhile the circulatory function of glymphatic system was detected by tracer injection at P8 and P32. On P30-P32, behavior tests including open field test, novel object recognition test, and Y-maze test were conducted. Primary astrocyte cultures were established and treated with the PI3K activator 740Y-P, dexmedetomidine, and small interfering RNA (siRNA) to silence ΔFosB. We propose for the first time that multiple exposure to sevoflurane induces circulatory dysfunction of the glymphatic system in young mice. Dexmedetomidine improves the circulatory capacity of the glymphatic system in young mice following repeated exposure to sevoflurane through the PI3K/AKT/ΔFosB/AQP4 signaling pathway, and enhances their long-term learning and working memory abilities.

Ketamine administration causes cognitive impairment by destroying the circulation function of the glymphatic system.

BACKGROUND: Ketamine, as a non-competitive antagonist of N-methyl-D-aspartate (NMDA) receptors, was originally used in general anesthesia. Epidemiological data show that ketamine has become one of the most commonly abused drugs in China. Ketamine administration might cause cognitive impairment; however, its molecular mechanism remains unclear. The glymphatic system is a lymphoid system that plays a key role in metabolic waste removal and cognitive regulation in the central nervous system. METHODS: Focusing on the glymphatic system, this study evaluated the behavioral performance and circulatory function of the glymphatic system by building a short-term ketamine administration model in mice, and detected the expression levels of the 5-HT2c receptor, ΔFosb, Pten, Akt, and Aqp4 in the hippocampus. Primary astrocytes were cultured to verify the regulatory relationships among related indexes using a 5-HT2c receptor antagonist, a 5-HT2c receptor short interfering RNA (siRNA), and a ΔFosb siRNA. RESULTS: Ketamine administration induced ΔFosb accumulation by increasing 5-HT2c receptor expression in mouse hippocampal astrocytes and primary astrocytes. ΔFosb acted as a transcription factor to recognize the AATGATTAAT bases in the 5' regulatory region of the Aqp4 gene (-1096 bp to -1087 bp), which inhibited Aqp4 expression, thus causing the circulatory dysfunction of the glymphatic system, leading to cognitive impairment. CONCLUSIONS: Although this regulatory mechanism does not involve the Pten/Akt pathway, this study revealed a new mechanism of ketamine-induced cognitive impairment in non-neuronal systems, and provided a theoretical basis for the safety of clinical treatment and the effectiveness of withdrawal.

Cell-specific mRNA alterations in Na+, K+-ATPase α and ß isoforms and FXYD in mice treated chronically with carbamazepine, an anti-bipolar drug.

Evidence accumulating during almost 50 years suggests Na(+), K(+)-ATPase dysfunction in bipolar disorder, a disease treatable with chronic administration of lithium salts, carbamazepine or valproic acid. Three Na(+), K(+)-ATPase α subunits (α1-3) and two ß subunits (ß1 and ß2) are expressed in brain together with the auxiliary protein FXYD7. FXYD7 decreases K(+) affinity, and thus contributes to stimulation of the enzyme at elevated extracellular K(+) concentrations. Na(+), K(+)-ATPase subtype and FXYD7 genes were determined by RT-PCR in mice co-expressing one fluorescent signal with an astrocytic marker or a different fluorescent signal with a neuronal marker and treated for 14 days with carbamazepine. Following fluorescence-activated cell sorting of neurons and astrocytes it was shown that α2 Expression was upregulated in astrocytes and neurons and α1 selectively in neurons, but α3 was unchanged. ß1 was upregulated in astrocytes, but not in neurons. ß2 was unaffected in astrocytes and absent in neurons. FXYD7 was downregulated specifically in neurons. According to cited literature data these changes should facilitate K(+) uptake in neurons, without compromising preferential uptake in astrocytes at increased extracellular K(+) concentrations. This process seems to be important for K(+) homeostasis of the cellular level of the brain (Xu et al. Neurochem Res E-pub Dec. 12, 2012).

Comparison between drug-induced and K⁺-induced changes in molar acid extrusion fluxes (JH⁺) and in energy consumption rates in astrocytes.

Neuronal excitation leads to an increase of the extracellular K(+) concentration ([K(+)]o) in brain. This increase has at least two energy-consuming consequences: (1) a depolarization-mediated change in intracellular pH (pHi) in astrocytes due to depolarization-mediated increased activity of the acid-extruding Na(+)/bicarbonate transporter NBCe1 (driven by secondary active transport, supported by ion gradients established by the Na(+), K(+)-ATPase); and (2) activation of cellular reuptake of K(+) mediated by the Na(+), K(+)-ATPase in both neurons and astrocytes. Astrocytic, but not neuronal increase in NBCe1 activity and pHi is also seen after chronic treatment with either of the two anti-bipolar drugs carbamazepine or valproic acid. The third 'classical' anti-bipolar drug, 'lithium' increases astrocytic pHi by a different mechanism (stimulation of the acid extruding Na(+)/H(+) exchanger NHE1). The acid extruder fluxes, which depend upon the change in pHi per time unit (ΔpHi/Δt) and intracellular buffering power, have not been established in most of these situations. Therefore their stimulatory effects on energy metabolism has not been quantitated. This has been done in the present study in cultured mouse astrocytes. pHi was determined using the fluorescent pH-sensitive indicator BCECF-AM and an Olympus IX71 live cell imaging fluorescence microscope. Molar acid extrusion fluxes (indicating transporter activity) were determined as pHi changes/min during recovery after acid-loading with NH3/NH4 (+), NBCe1 mRNA and protein expression in the cultured cells by, respectively RT-PCR and Western blotting. Drug-induced up-regulation of acid extrusion flux was slow and less than physiologically seen after increase in K(+) concentration. Energetically, K(+) uptake is much costlier than NBCe1 activity.

Beneficial effect of electroacupuncture on the distribution of foreign substances in the brain of rats developing depression-like behavior.

We used low and high molecular weight fluorescence tracers to investigate the entry of foreign solutes into the brain parenchyma and their exit from it by the glymphatic system, during experimentally induced depressive-like behavior in rats. The tail suspension test (TST), as an acute stressor, is known to induce such a type of behavior, considered to model the human major depressive disorder (MDD). Electroacupuncture (EAP) relieves both depressive-like behavior in rodents and the symptoms of MDD in humans. Here we report that 180 min after the intracisternal injection of the low molecular weight tracer Fluorescein-5-Isothiocianate Conjugated Dextran (FITC-d3), a 15-min duration TST tended to increase the control fluorescence in the brain of rats. Both EAP and sham EAP decreased the fluorescence of FITC-d3 in comparison with the TST, but not the control value. In addition, EAP and sham EAP counteracted the effects of TST. The high molecular weight tracer Ovalbumin Alexa Fluor 555 Conjugate (OA-45) failed to enter the brain parenchyma and accumulated at more superficial sites; however, EAP or sham EAP modified the distribution of fluorescence under TST application in a similar manner as that observed during the use of FITC-d3. It is concluded that EAP is possibly a valid treatment to slow down the entry of foreign solutes into the brain; in view of the comparable effects of EAP on FITC-d3 and OA-45 distribution, EAP seems to act before FITC-d3 passes the astroglial aquaporin-4 water channels, which are a critical constituent of the glymphatic system.

Novel pathogenesis of post-traumatic stress disorder studied in transgenic mice.

Posttraumatic stress disorder (PTSD) is very common after exposure to trauma, mental stress or violence. Because objective biological markers for PTSD are lacking, exactly diagnosing PTSD is a challenge for clinical psychologists. In-depth research on the pathogenesis of PTSD is a key for solving this problem. In this work, we used male Thy1-YFP transgenic mice, in which neurons are fluorescently labeled, to research the effects of PTSD on neurons in vivo. We initially discovered that pathological stress associated with PTSD increased the activation of glycogen synthesis kinase-beta (GSK-3ß) in neurons and induced the translocation of the transcription factor forkhead box-class O3a (FoxO3a) from the cytoplasm to the nucleus, which decreased the expression of uncoupling protein 2 (UCP2) and increased mitochondrial production of reactive oxygen species (ROS) to trigger neuronal apoptosis in the prefrontal cortex (PFC). Furthermore, the PTSD model mice showed increased freezing and anxiety-like behaviors and more severe decrease of memory and exploratory behavior. Additionally, leptin attenuated neuronal apoptosis by increasing the phosphorylation of signal transducer and activator of transcription 3 (STAT3), which further elevated the expression of UCP2 and inhibited the mitochondrial production of ROS induced by PTSD, thus reducing neuronal apoptosis and ameliorating PTSD-related behaviors. Our study is expected to promote the exploration of PTSD-related pathogenesis in neural cells and the clinical effectiveness of leptin for PTSD.