Neuroepigenetic Changes in DNA Methylation Affecting Diabetes-Induced Cognitive Impairment.

Chronic diabetic conditions have been associated with certain cerebral complications, that include neurobehavioral dysfunctional patterns and morphological alterations of neurons, especially the hippocampus. Neuroanatomical studies done by the authors have shown decreased total dendritic length, intersections, dendritic length per branch order and nodes in the CA1 hippocampal region of the diabetic brain as compared to its normal control group, indicating reduced dendritic arborization of the hippocampal CA1 neurons. Epigenetic alterations in the brain are well known to affect age-associated disorders, however its association with the evolving diabetes-induced damage in the brain is still not fully understood. DNA hypermethylation within the neurons, tend to silent the gene expression of several regulatory proteins. The findings in the study have shown an increase in global DNA methylation in palmitic acid-induced lipotoxic Neuro-2a cells as well as within the diabetic mice brain. Inhibiting DNA methylation, restored the levels of HSF1 and certain HSPs, suggesting plausible effect of DNMTs in maintaining the proteostasis and synaptic fidelity. Neuroinflammation, as exhibited by the astrocyte activation (GFAP), were further significantly decreased in the 5-azadeoxycytidine group (DNMT inhibitor). This was further evidenced by decrease in proinflammatory cytokines TNF⍺, IL-6, and mediators iNOS and Phospho-NFkB. Our results suggest that changes in DNA methylation advocate epigenetic dysregulation and its involvement in disrupting the synaptic exactitude in the hippocampus of diabetic mice model, providing an insight into the pathophysiology of diabetes-induced neuroepigenetic changes.

Mifepristone blocks the anxiolytic- and antidepressant-like effects of allopregnanolone in male rats.

BACKGROUND: Allopregnanolone (3α, 5α-tetrahydroprogesterone) is an inhibitory neurosteroid synthesized from progesterone via 5α-reductase activity in the brain and has anxiolytic, antidepressant, sedative, anticonvulsant, and analgesic activity. Altered levels of allopregnanolone cause anxiety, depression, premenstrual syndrome, and psychiatric disorders. Although allopregnanolone exerts most of its actions by modulating GABAA receptor, NMDA receptor, BDNF expression, and PXR activity, a recent study showed its effects are blocked by mifepristone on lordosis behavior which indicates the involvement of progestin or glucocorticoid receptors in the effects of allopregnanolone since mifepristone blocks both these receptors. However, whether these receptors are involved in acute anxiolytic or antidepressant-like effects is unknown. METHODS: Adult male Wistar rats were used to study whether the prior administration of mifepristone would alter the effects of allopregnanolone in the elevated plus maze (EPM) and forced swim test (FST) was evaluated. RESULTS: 10 mg/Kg dose of allopregnanolone increased percent open arm entries in the EPM, whereas 3 mg/Kg dose of allopregnanolone decreased percent immobility in the FST. Mifepristone administration resulted in a U-shaped response in the FST (with 1 mg/Kg, s.c., decreasing the immobility time) without significantly impacting the behavior in the EPM. In combination studies, mifepristone blocked the anxiolytic and antidepressant effects of allopregnanolone. CONCLUSION: The current study provides evidence for the first time that progestin or glucocorticoid receptors are involved in the acute anxiolytic and antidepressant effects of allopregnanolone. Understanding the mechanism of action of allopregnanolone will help us design better therapeutic strategies to treat neuropsychiatric diseases such as depression and anxiety.

Antimicrobial activity, toxicity and accumulated hard-tissue debris (AHTD) removal efficacy of several chelating agents.

AIM: To evaluate the antimicrobial, toxicity and cleaning effectiveness of ethylenediaminetetraacetic acid (EDTA) and maleic acid (MA) alone and combined with cetrimide (CTR). METHODOLOGY: Cytotoxic and genotoxic effects were assessed on Chinese hamster cells V79 using the MTT, clonogenic and micronucleus assays, respectively. The bacterial inhibitory and bactericidal concentrations (MIC and MBC, respectively) were determined on a strain of Enterococcus faecalis. Antimicrobial tests were performed on a biofilm model after treatment with the chelating agents by using a biofilm eradication concentration (MBEC) and confocal laser scanning microscope (CLSM) assays. Quantification of cell biomass and percentage of live and dead cells in the biomass were assessed for each group. The percentage reduction of accumulated hard-tissue debris (AHTD) after root canal preparation and final irrigation protocols was evaluated by micro-CT. Statistical tests of one-way analysis of variance (anova), Bonferroni test, Kruskal-Wallis test, Dunn's multiple comparison test and Wilcoxon matched-pairs signed-rank tests were used. RESULTS: Cetrimide alone as well as in combination with EDTA and MA at dilutions of 1/10 and 1/100 was significantly more toxic as compared to untreated controls (P < 0.001). All tested mixtures were nontoxic at a dilution of 1/1000. EDTA retained a weak inhibitory and bactericidal effect against planktonic cells, whilst MA inhibited cells growth and killed 99.9% of the cells when diluted. CTR revealed the most prominent effect, being inhibitory and bactericidal, also when diluted. Cetrimide alone or combined with EDTA was able to remove, respectively, 40% (P < 0.01) and 60% (P < 0.001) of the entire biomass after 1 min. Conversely, MA alone and in combination with CTR did not have a significant effect on biomass reduction. After final irrigation, the AHTD volume was significantly decreased in all groups (P < 0.05). EDTA + CTR and MA + CTR were associated with a significant reduction in the percentage of AHTD on the entire root canal compared to the same solutions without surfactant. CONCLUSIONS: 7% MA was less cytotoxic in comparison with 17% EDTA. The addition of cetrimide to EDTA and MA removed accumulated hard-tissue debris effectively from the canal walls and increased their antimicrobial activity when compared to the same solutions without detergents.

Measurement of the Electrical Properties of a Thundercloud Through Muon Imaging by the GRAPES-3 Experiment.

The GRAPES-3 muon telescope located in Ooty, India records rapid (∼10 min) variations in the muon intensity during major thunderstorms. Out of a total of 184 thunderstorms recorded during the interval of April 2011-December 2014, the one on December 1, 2014 produced a massive potential of 1.3 GV. The electric field measured by four well-separated (up to 6 km) monitors on the ground was used to help estimate some of the properties of this thundercloud, including its altitude and area that were found to be 11.4 km above mean sea level and ≥380 km^{2}, respectively. A charging time of 6 min to reach 1.3 GV implied the delivery of a power of ≥2 GW by this thundercloud that was moving at a speed of ∼60 km h^{-1}. This work possibly provides the first direct evidence for the generation of gigavolt potentials in thunderclouds that could also possibly explain the production of highest-energy (100 MeV) gamma rays in the terrestrial gamma-ray flashes.

Chemical, cytotoxic and genotoxic analysis of etidronate in sodium hypochlorite solution.

AIM: To test whether the incorporation of a chelation powder, etidronate, marketed for root canal irrigation (Dual Rinse HEDP) into a sodium hypochlorite (NaOCl) solution induced additional cytotoxic and genotoxic effects not observed with NaOCl alone. METHODOLOGY: Fresh and 24-h-old mixtures of 0.9 g of etidronate in 10 mL of 2.5% NaOCl were assessed for their basic chemical features including pH and the ability to chelate Ca2+ from hydroxylapatite. Pure NaOCl and phosphate-buffered saline (PBS) with/without etidronate served as control solutions. Cytotoxic and genotoxic effects of diluted solutions (1:10, 1:100, and 1:1000) were assessed on Chinese hamster lung fibroblast (V79) using the MTT, clonogenic and micronucleus assays, respectively. One-way ANOVA and Tukey's HSD test were applied with an alpha-type error of 5% (P < 0.05). RESULTS: In mixtures of NaOCl and etidronate, the free available chlorine was lost completely after 24 h, and the pH dropped by more than 3 units. However, the ability of the etidronate to chelate Ca2+ was maintained. The fresh mixtures of NaOCl and etidronate were not more toxic than NaOCl alone (P > 0.05), whilst the 24-h-old mixtures were less toxic (P < 0.05) and statistically similar to pure etidronate. Etidronate per se showed little cytotoxicity and no genotoxicity at the tested dilutions. CONCLUSIONS: The ability of the used etidronate, Dual Rinse HEDP, to chelate calcium is not affected by NaOCl. Cytotoxicity and genotoxicity of mixed solutions is dictated by the presence of free available chlorine therein.

Contrasting effects of pre-training on acquisition of operant and radial arm maze tasks in rats.

Performing multiple tasks either simultaneously, in rapid alternation or in succession, is routine in daily life. Further, testing rodents in a battery of tests is common both in drug discovery and behavioral phenotyping research. However, learning of new tasks can be influenced by prior experience(s). There has been some research on 'switching cost' involved in the transition from one behavior to another. However, there has been no specific assessment of the effect of learning an operant paradigm on performance in a spatial memory task and vice versa. Accordingly, we evaluated task switching between two forms of learning paradigms, operant conditioning and radial arm maze (RAM) tasks. In experiment 1, rats were trained for operant conditioning with food reward followed by a partially baited RAM task. In experiment 2, rats were trained first on a RAM task followed by operant learning. Pre-training on the operant task, impaired the acquisition of the RAM. On the contrary, pre-training on the RAM enhanced operant performance. Our study reveals significant effects of the test order on task-switching in rats. This knowledge can be useful when framing test sequences in test batteries for drug discovery research and screening genetically modified mice.

Pharmacological approach to increasing the retention of radiation-induced γ-H2AX foci using phosphatase inhibitors: significance in radiation biodosimetry.

In a scenario of accidental mass radiation exposure transportation and analysis of samples may take some time, resulting in loss of biomarker information over this period. The present study aims to use phosphatase inhibitors for longer retention of focal signals to adopt γ-H2AX as a biodosimetric biomarker for the management of early triage. Peripheral blood lymphocytes isolated from healthy individuals were irradiated in vitro with x-rays and γ-H2AX foci were analysed using fluorescent microscopy and flow cytometric methods. Further, the effect of protein phosphatase 2A inhibitors such as calyculin A, fostriecin and okadiac acid on the retention of foci was studied. Fluorescent microscopy was found to be a more sensitive method than flow cytometry. Calyculin A showed significant retention of focal signals at 6 h with 1.5-fold increased retention compared to radiation alone; this may prove beneficial in early triage management because of a better dose approximation.

Inactivation of basolateral amygdala prevents chronic immobilization stress-induced memory impairment and associated changes in corticosterone levels.

Chronic stress causes detrimental effects on various forms of learning and memory. The basolateral amygdala (BLA) not only plays a crucial role in mediating certain forms of memory, but also in the modulation of the effects of stress. Chronic immobilization stress (CIS) results in hypertrophy of the BLA, which is believed to be one of the underlying causes for stress' effects on learning. Thus, it is plausible that preventing the effects of CIS on amygdala would preclude its deleterious cognitive effects. Accordingly, in the first part, we evaluated the effect of excitotoxic lesion of the BLA on chronic stress-induced hippocampal-dependent spatial learning using a partially baited radial arm maze task. The BLA was ablated bilaterally using ibotenic acid prior to CIS. Chronically stressed rats showed impairment in spatial learning with decreased percentage correct choice and increased reference memory errors. Excitotoxic lesion of the BLA prevented the impairment in spatial learning and reference memory. In the retention test, lesion of the BLA was able to rescue the chronic stress-induced impairment. Interestingly, stress-induced enhanced plasma corticosterone levels were partially prevented by the lesion of BLA. These results motivated us to evaluate if the same effects can be observed with temporary inactivation of BLA, only during stress. We found that chronic stress-induced spatial learning deficits were also prevented by temporary inactivation of the BLA. Additionally, temporary inactivation of BLA partially precluded the stress-induced increase in plasma corticosterone levels. Thus, inactivation of BLA precludes stress-induced spatial learning deficits, and enhanced plasma corticosterone levels. It is speculated that BLA inactivation-induced reduction in corticosterone levels during stress, might be crucial in restoring spatial learning impairments. Our study provides evidence that amygdalar modulation during stress might be beneficial for strategic management of stress-related cognitive deficits.

Enriched environment ameliorates depression-induced cognitive deficits and restores abnormal hippocampal synaptic plasticity.

Severe depression compromises structural and functional integrity of the brain and results in impaired learning and memory, maladaptive synaptic plasticity as well as degenerative changes in the hippocampus and amygdala. The precise mechanisms underlying cognitive dysfunctions in depression remain largely unknown. On the other hand, enriched environment (EE) offers beneficial effects on cognitive functions, synaptic plasticity in the hippocampus. However, the effect of EE on endogenous depression associated cognitive dysfunction has not been explored. Accordingly, we have attempted to address this issue by investigating behavioural, structural and synaptic plasticity mechanisms in an animal model of endogenous depression after exposure to enriched environment. Our results demonstrate that depression is associated with impaired spatial learning and enhanced anxiety-like behaviour which is correlated with hypotrophy of the dentate gyrus and amygdalar hypertrophy. We also observed a gross reduction in the hippocampal long-term potentiation (LTP). We report a complete behavioural recovery with reduced indices of anhedonia and behavioural despair, reduced anxiety-like behaviour and improved spatial learning along with a complete restoration of dentate gyrus and amygdalar volumes in depressive rats subjected to EE. Enrichment also facilitated CA3-Schaffer collateral LTP. Our study convincingly proves that depression-induces learning deficits and impairs hippocampal synaptic plasticity. It also highlights the role of environmental stimuli in restoring depression-induced cognitive deficits which might prove vital in outlining more effective strategies to treat major depressive disorders.

Transient Weakening of Earth's Magnetic Shield Probed by a Cosmic Ray Burst.

The GRAPES-3 tracking muon telescope in Ooty, India measures muon intensity at high cutoff rigidities (15-24 GV) along nine independent directions covering 2.3 sr. The arrival of a coronal mass ejection on 22 June 2015 18:40 UT had triggered a severe G4-class geomagnetic storm (storm). Starting 19:00 UT, the GRAPES-3 muon telescope recorded a 2 h high-energy (∼20 GeV) burst of galactic cosmic rays (GCRs) that was strongly correlated with a 40 nT surge in the interplanetary magnetic field (IMF). Simulations have shown that a large (17×) compression of the IMF to 680 nT, followed by reconnection with the geomagnetic field (GMF) leading to lower cutoff rigidities could generate this burst. Here, 680 nT represents a short-term change in GMF around Earth, averaged over 7 times its volume. The GCRs, due to lowering of cutoff rigidities, were deflected from Earth's day side by ∼210° in longitude, offering a natural explanation of its night-time detection by the GRAPES-3. The simultaneous occurrence of the burst in all nine directions suggests its origin close to Earth. It also indicates a transient weakening of Earth's magnetic shield, and may hold clues for a better understanding of future superstorms that could cripple modern technological infrastructure on Earth, and endanger the lives of the astronauts in space.

Rescue of fragile X syndrome phenotypes in Fmr1 KO mice by the small-molecule PAK inhibitor FRAX486.

Fragile X syndrome (FXS) is the most common inherited form of autism and intellectual disability and is caused by the silencing of a single gene, fragile X mental retardation 1 (Fmr1). The Fmr1 KO mouse displays phenotypes similar to symptoms in the human condition--including hyperactivity, repetitive behaviors, and seizures--as well as analogous abnormalities in the density of dendritic spines. Here we take a hypothesis-driven, mechanism-based approach to the search for an effective therapy for FXS. We hypothesize that a treatment that rescues the dendritic spine defect in Fmr1 KO mice may also ameliorate autism-like behavioral symptoms. Thus, we targeted a protein that regulates spines through modulation of actin cytoskeleton dynamics: p21-activated kinase (PAK). Our results demonstrate that a potent small molecule inhibitor of group I PAKs reverses dendritic spine phenotypes in Fmr1 KO mice. Moreover, this PAK inhibitor--which we call FRAX486--also rescues seizures and behavioral abnormalities such as hyperactivity and repetitive movements, thereby supporting the hypothesis that a drug treatment that reverses the spine abnormalities can also treat neurological and behavioral symptoms. Finally, a single administration of FRAX486 is sufficient to rescue all of these phenotypes in adult Fmr1 KO mice, demonstrating the potential for rapid, postdiagnostic therapy in adults with FXS.

The selective noradrenergic reuptake inhibitor reboxetine restores spatial learning deficits, biochemical changes, and hippocampal synaptic plasticity in an animal model of depression.

Depression is a major psychiatric illness that is associated with cognitive dysfunctions. The underlying mechanism of depression-associated memory impairment is unclear. Previously, we showed altered hippocampal synaptic plasticity in an animal model of depression. Although several antidepressants are beneficial in the treatment of depression, very little is known about the effects of these drugs on depression-associated learning and memory deficits. Prolonged antidepressant treatment might contribute to neuroplastic changes required for clinical outcomes. Accordingly, we evaluated the effect of chronic reboxetine (a selective noradrenergic reuptake inhibitor) treatment on depression-induced reduced hippocampal synaptic plasticity, neurotransmitter levels, and spatial learning and memory impairments. Depression was induced in male Wistar rats by the administration of clomipramine from postnatal days 8 to 21, and these rats were treated with reboxetine in adulthood. The neonatal clomipramine administration resulted in impaired hippocampal long-term potentiation (LTP), decreased hippocampal cholinergic activity and monoamine levels, and poor performance in a partially baited eight-arm radial maze task. Chronic reboxetine treatment restored the hippocampal LTP, acetylcholinesterase activity, and levels of biogenic amines and ameliorated spatial learning and memory deficits in the depressed state. Thus, restoration of hippocampal synaptic plasticity might be a cellular mechanism underlying the beneficial effect of reboxetine in depression-associated cognitive deficits. This study furthers the existing understanding of the effects of antidepressants on learning, memory, and synaptic plasticity and could ultimately assist in the development of better therapeutic strategies to treat depression and associated cognitive impairments.

Anxiety-, and depression-like behavior following short-term finasteride administration is associated with impaired synaptic plasticity and cognitive behavior in male rats.

Finasteride, a 5α-Reductase inhibitor, is used to treat male pattern baldness and benign prostatic hyperplasia. Several clinical studies show that chronic finasteride treatment induces persistent depression, suicidal thoughts and cognitive impairment and these symptoms are persistent even after its withdrawal. Previous results from our lab showed that repeated administration of finasteride for six days induces depression-like behavior. However, whether short-term finasteride administration induces anxiety-like behavior and memory impairment and alters synaptic plasticity are not known, which formed the basis of this study. Finasteride was administered to 2-2.5 months old male Wistar rats for six days and subjected to behavioral evaluation, biochemical estimation and synaptic plasticity assessment. Anxiety-like behavior was evaluated in the elevated plus maze (EPM), open field test (OFT), light/dark test (LDT), and novelty suppressed feeding test (NSFT), and learning and memory using novel object recognition test (NORT) and novel object location test (NOLT) and depression-like behavior in the sucrose preference test (SPT). Synaptic plasticity in the hippocampal Schaffer collateral-CA1 was evaluated using slice field potential recordings. Plasma corticosterone levels were estimated using ELISA. Finasteride administration induced anxiety-like behavior in the EPM, OFT, LDT and NSFT, and depression-like behavior in the SPT. Further, finasteride induced hippocampal dependent spatial learning and memory impairment in the NOLT. In addition, finasteride decreased basal synaptic plasticity and long-term potentiation (LTP) in the hippocampus. A trend of increased plasma corticosterone levels was observed following repeated finasteride administration. These results indicate the potential role of corticosterone and synaptic plasticity in finasteride-induced effects and further studies will pave way for the development of novel neurosteroid-based therapeutics in neuropsychiatric diseases.

Gallic acid: a polyphenolic compound potentiates the therapeutic efficacy of cisplatin in human breast cancer cells.

Gallic acid (GA) is a natural polyhydroxyphenolic compound with antioxidant, antimutagenic, anti-inflammatory, and antineoplastic activities. Cisplatin (CPT) is a platinum-based chemotherapeutic drug, and it is the treatment of choice for breast, ovarian, testicular, head, and neck cancers. However, the use of anticancer drugs has undesirable effects on patients due to associated toxicities. Thus, it is necessary to search for alternatives that reduce unintended side effects and enhance anticancer potential. The use of natural compounds with the conventional chemotherapeutic drug is a new aspect of cancer therapy. In the present study, we evaluated the ability of GA in the modulation of anticancer effects of CPT in human breast adenocarcinoma cells (MCF-7) by performing MTT, apoptosis, clonogenic cell survival, and micronucleus assays. GA and CPT showed significant cytotoxic activities in MCF-7 cells in a dose-dependent manner. In combination therapy (GA 2.5, 5.0, and 10 µg/mL + CPT10 µg/mL), GA synergistically reduced the MCF-7 cell viability in contrast to the individual therapies. Cancer cells death by GA is through the induction of apoptosis as observed in the acridine orange and ethidium bromide dual staining method. The frequency of micronuclei (MN) was decreased significantly (P < 0.001) in combinational therapy, possibly reducing the risk of chemotherapy-induced MN. Moreover, GA in mono or combinational therapy did not induce any cytotoxic effects in normal breast epithelial cells (MCF-10A). GA did not show any significant difference in colony inhibition compared to CPT. This outcome shows its differential effects in normal and cancerous cells. Hence, the combination GA with chemotherapeutic drugs could represent a promising alternative therapy in cancer treatment with minimal side effects.

Risky decision-taking task: A novel paradigm to assess the risk-taking behaviour in rats predisposed to early-life stress.

One of the characteristic features of adolescence is risk-taking behavioural traits. Uncontrolled risk-taking without proper assessment may have harmful impact on mental health later in life. Therefore, it is essential to identify it early for the preventable health problems. In the present study, we have designed a novel paradigm, viz. Risky Decision-taking Task (RDTT), to evaluate the spontaneous risk-taking behavioural repertoire in adolescent rodents. The task was designed based on both risk and cognitive factors. To validate and compare the risk-taking tendency, we have used early maternal separation and isolation (MS) stress model, as it is known to increase anxiety and curiosity-like behaviour at adolescence. We have used Sprague-Dawley rats of both sexes. Rats were exposed to MS stress for 10 days daily for six hours during stress hyporesponsive period (SHRP) from postnatal day 4-13. These rats were subjected to RDTT during adolescence. This task is a reward-based task where the latency to collect reward in the presence or absence of a risk factor is assessed. It consists of habituation, training to find the location of small and large rewards, reward preference for small and large reward and testing period under risky situation. Rats were trained individually to retrieve the valuation-based rewards under the risky, but innate aversive environments. The results from RDTT showed that as compared to controls, MS rats from both sexes showed reduced latency to collect large reward in the presence of a risk element and a reduced risk-index which is indicative of a higher risk-taking tendency in these rats. In addition, MS rats showed a trend towards anxiety-like behaviour as compared to controls in the Light-Dark Test. These results together show decreased risk latency for the large reward and reduced risk assessment in MS rats which is suggestive of more risk-taking tendency in these rats. Thus, we propose that RDTT paradigm can be used to evaluate the spontaneous risk-taking behavioural repertoire based on innate, spontaneous aversion and cognitive factors in rats.

Arterolane maleate plus piperaquine phosphate for treatment of uncomplicated Plasmodium falciparum malaria: a comparative, multicenter, randomized clinical trial.

BACKGROUND: Artemisinin-based combination therapy is the first-line treatment for uncomplicated falciparum malaria. This study assessed the antimalarial efficacy and safety of a combination of 150 mg of arterolane maleate and 750 mg of piperaquine phosphate (AM-PQP) in comparison to Coartem (artemether and lumefantrine) in patients with acute uncomplicated P. falciparum malaria. METHODS: In this open-label, randomized, multicentric, parallel group clinical trial, 240 patients were randomized to receive AM-PQP (160 patients) or Coartem (80 patients). Patients with P. falciparum monoinfection and initial parasite densities ranging from 1000 to 100 000 asexual parasites/µL of blood were followed for 28 days. Polymerase chain reaction-corrected adequate clinical and parasitologic response on day 28, parasite clearance time, and fever clearance time were evaluated. RESULTS: A total of 151 (94.4%) of 160 patients in the AM-PQP group completed the trial, while 77 (96.3%) of 80 patients in the Coartem group completed the trial. No treatment failure was noted in the AM-PQP group, while one patient receiving Coartem failed treatment on day 28. There was no difference in the median parasite clearance time (30 hours in both groups) or median fever clearance time (24 hours in both groups) after administration of the 2 study treatments. CONCLUSIONS: The available data support the evaluation of a drug combination in a larger population as a fixed-dose combination. Clinical Trials Registration. CTRI/2007/091/000031.

Reversal of stress-induced dendritic atrophy in the prefrontal cortex by intracranial self-stimulation.

The mammalian prefrontal cortex (PFC) has been implicated in a variety of motivational and emotional processes underlying working memory, attention and decision making. The PFC receives dopaminergic projections from the ventral tegmental area (VTA) and contains high density of D1 and D2 receptors and these projections are important in higher integrative cortical functions. The neurons of the PFC have been shown to undergo atrophy in response to stress. In an earlier study, we demonstrated that the chronic stress-induced atrophy of hippocampal neurons and behavioral impairment in the T-maze task were reversed by the activation of dopaminergic pathway by intracranial self-stimulation (ICSS) of the VTA. The stress-induced decrease in hippocampal dopamine (DA) levels was also restored by ICSS. Whether the reversal of stress-induced behavioral deficits by ICSS involves changes in the morphology of PFC neurons is unknown and the current study addresses this issue. Male Wistar rats underwent 21 days of restraint stress followed by ICSS for 10 days. The dendritic morphology of the PFC neurons was studied in Golgi-impregnated sections. Stress produced atrophy of the layer II/III and V PFC pyramidal neurons and ICSS to naïve rats significantly increased the dendritic arborization of these neurons compared to control. Interestingly, ICSS of stressed rats resulted in the reversal of the dendritic atrophy. Further, these structural changes were associated with a restored tissue levels of DA, norepinephrine and serotonin in the PFC. These results indicate that the behavioral restoration in stressed rats could involve changes in the plasticity of the PFC neurons and these results further our understanding of the role of dopaminergic neurotransmitter system in the amelioration of stress-induced deficits.

Cell cycle synchronization of bison (Bos gaurus) fibroblasts derived from ear piece collected post-mortem.

Efficiency of the technique of somatic cell nuclear transfer critically depends on the cell cycle phase compatibility between the donor somatic cell nucleus and recipient cytoplasm. In this study, attempts were made to optimize conditions for cell cycle synchronization of bison ear fibroblasts at G0/G1 using different approaches such as using cells in confluency, after contact inhibition, serum starvation or treatment with dimethyl sulfoxide (DMSO) (0.5%, 1.0% and 2.0%), sodium butyrate (NaBu) (0.5, 1.0 and 2.0 mm), cytochalasin-B (CB) (7.5 µg/ml), cycloheximide (CHX) (7.5 µg/ml) and 6-dimethyl aminopurine (6-DMAP) (2.0 mm). A small piece of an ear of an adult female bison collected post-mortem 10 h after death was used for the preparation of fibroblast cells. The synchronization efficiency was determined by fluorescence-activated cell sorting. Higher proportion of G0/G1 phase was obtained when cells were subjected to serum starvation for 48 h (85.4%). Sodium butyrate had no effect on synchronization of cells at G0/G1 when the cells were treated for 24 and 48 h. Similarly, DMSO (0.5% and 1.0%) had also no effect on the proportion of cells at G0/G1 for 24 and 48 h. The synchronization ability of CB, CHX and 6-DMAP at G0/G1 phase was equally effective when cells were treated for 4 h (68.5%, 68.7% and 67.4%) and 24 h (67.8%, 66.1% and 67.5%). In conclusion, this study shows that cells subjected to serum starvation for 24-48 h or confluent monolayer, or cycling cells treated with 1.0% DMSO or 2.0 mm NaBu for 24 h showed best synchronization in G0/G1 phase of cell cycle.

Mangiferin, a dietary xanthone protects against mercury-induced toxicity in HepG2 cells.

Mercury is one of the noxious heavy metal environmental toxicants and is a cause of concern for human exposure. Mangiferin (MGN), a glucosylxanthone found in Mangifera indica, reported to have a wide range of pharmacological properties. The objective of this study was to evaluate the cytoprotective potential of MGN, against mercury chloride (HgCl(2) ) induced toxicity in HepG2 cell line. The cytoprotective effect of MGN on HgCl(2) induced toxicity was assessed by colony formation assay, while antiapoptotic effect by fluorescence microscopy, flow cytometric DNA analysis, and DNA fragmentation pattern assays. Further, the cytoprotective effect of MGN against HgCl(2) toxicity was assessed by using biochemical parameters like reduced glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) by spectrophotometrically, mitochondrial membrane potential by flowcytometry and the changes in reactive oxygen species levels by DCFH-DA spectrofluoremetric analysis. A significant increase in the surviving fraction was observed with 50 µM of MGN administered two hours prior to various concentrations of HgCl(2) . Further, pretreatment of MGN significantly decreased the percentage of HgCl(2) induced apoptotic cells. Similarly, the levels of ROS generated by the HgCl(2) treatment were inhibited significantly (P < 0.01) by MGN. MGN also significantly (P < 0.01) inhibited the HgCl(2) induced decrease in GSH, GST, SOD, and CAT levels at all the post incubation intervals. Our study demonstrated the cytoprotective potential of MGN, which may be attributed to quenching of the ROS generated in the cells due to oxidative stress induced by HgCl(2) , restoration of mitochondrial membrane potential and normalization of cellular antioxidant levels.

Mifepristone's effects on depression- and anxiety-like behavior in rodents.

Mifepristone is a non-selective progesterone (PR), glucocorticoid (GR), and androgen receptor (AR) antagonist with antidepressant and anxiolytic effects. The dose and duration of mifepristone administration vary in rodent preclinical studies to evaluate depression-like and anxiety-like behavior. This review summarizes the findings so far and attempts to reconcile some of the differences in the results. While a few studies assessed basal depression- and anxiety-like behavior, several studies have used mifepristone in conjunction with stress, corticosterone/dexamethasone (after adrenalectomy), or progesterone administration. The effect of mifepristone on depression-like behavior appears to depend not only on the dose and duration of administration but also on the intensity or type of stress. In addition, the anxiolytic effects may depend on the species and strain of the experimental animals. More reports assess antidepressant-like or anxiolytic-like effects following acute than chronic administration. These effects are dependent on the paradigms and the nature of stressors. Most mifepristone studies implicate the role of GRs, yet only two reports have confirmed its role using a genetic approach, whereas none implicate the role of PRs/ARs. There are several novel selective GR antagonists whose effects on depression- and anxiety-like behavior are yet to be studied. Future studies could aim to confirm the role of GRs and evaluate the contribution of PRs/ARs to the effects of mifepristone. Such studies will contribute to a better understanding of depression, anxiety, and other mood disorders and develop novel strategies, particularly for treatment-resistant conditions.