Amelioration of diabetes-induced cognitive impairment by Transient Receptor Potential Vanilloid 2 (TRPV2) channel inhibitor: Behavioral and mechanistic study.

Transient receptor potential (TRP) channels are Ca2+ permeable non-selective cation channels which play a pivotal role in diabetes and diabetic complications. Among diabetic complications, diabetes-induced cognitive impairment is a major CNS complication. The role of several TRP channels has been investigated extensively for their diverse Ca2+ regulating mechanism, and recently their role has been postulated in the progression of neurodegenerative disorders. However, the role of TRPV2 has not been investigated yet. Therefore, in the present study, the involvement of TRPV2 channels was investigated in diabetes-induced cognitive impairment using TRPV2 inhibitor, tranilast. High glucose exposure in rat C6 glial cells enhances the Ca2+-entry through TRPV2 channels. In our in-vivo study, diabetic rats showed increased gene and protein expression of TRPV2 in the hippocampus. Subsequent increase in the acetylcholinesterase activity in the cortex, as well as decrease in the phosphorylation of Ca2+/calmodulin-dependent protein kinase II (p-CaMKII-Thr-286), p-GSK-3ß (Ser-9), p-CREB (Ser-133) and postsynaptic density protein 95 (PSD-95) in the hippocampus were also observed this led to the impairment in the learning and memory as evident from behavioral parameters such as Morris water maze test, passive avoidance and Y-maze test paradigm. Three-week treatment with tranilast (30 and 100 mg/kg, p.o.) showed improvement in learning and memory associated behaviours (Morris water maze test, passive avoidance, and Y-maze test) by increasing the p-CaMKII (Thr-286), p-GSK-3ß (Ser-9), p-CREB (Ser-133) and PSD-95 in the hippocampus. Cortical acetylcholinesterase activity was also reduced by the tranilast. These findings depicted that TRPV2 inhibition may be an effective treatment strategy in diabetes-induced cognitive deficits.

Transient receptor potential (TRP) channels: a metabolic TR(i)P to obesity prevention and therapy.

Cellular transport of ions, especially by ion channels, regulates physiological function. The transient receptor potential (TRP) channels, with 30 identified so far, are cation channels with high calcium permeability. These ion channels are present in metabolically active tissues including adipose tissue, liver, gastrointestinal tract, brain (hypothalamus), pancreas and skeletal muscle, which suggests a potential role in metabolic disorders including obesity. TRP channels have potentially important roles in adipogenesis, obesity development and its prevention and therapy because of their physiological properties including calcium permeability, thermosensation and taste perception, involvement in cell metabolic signalling and hormone release. This wide range of actions means that organ-specific actions are unlikely, thus increasing the possibility of adverse effects. Delineation of responses to TRP channels has been limited by the poor selectivity of available agonists and antagonists. Food constituents that can modulate TRP channels are of interest in controlling metabolic status. TRP vanilloid 1 channels modulated by capsaicin have been the most studied, suggesting that this may be the first target for effective pharmacological modulation in obesity. This review shows that most of the TRP channels are potential targets to reduce metabolic disorders through a range of mechanisms.

Lactobacillus plantarum MTCC 9510 supplementation protects from chronic unpredictable and sleep deprivation-induced behaviour, biochemical and selected gut microbial aberrations in mice.

AIM: Here, we evaluated any beneficial effects of a potential probiotic bacterial strain (Lactobacillus plantarum MTCC 9510) in two different stress paradigms in mice. METHODS AND RESULTS: Lactobacillus plantarum MTCC 9510 (2 × 1010 CFU per mice) was supplemented to male Swiss albino mice either subjected to chronic unpredictable mild stress or sleep deprivation (SD) stress. Various behavioural and biochemical tests along with selected gut bacterial abundances were determined. Lactobacillus plantarum MTCC 9510 supplementation prevented stress-induced behavioural despair (depression, anxiety, learning and memory, stereotypic behaviour), oxidative stress markers and inflammatory cytokines in brain and serum. Its supplementation also improved gut and blood brain barrier integrity. It also affected caecal short-chain fatty acids along with the promotion of Lactobacillus sp. and reduction in Enterobacteriaceae abundances. We also observed that two different stresses variably affected various behavioural and biochemical changes but L. plantarum MTCC 9510 supplementation most effectively prevented all these changes. CONCLUSION: We provide evidence that positive modulation of the selected beneficial gut microbial population could serve as a viable strategy to neutralize day-to-day and SD stress-induced pathological alterations. SIGNIFICANCE AND IMPACT OF THE STUDY: Therapeutic potential of this/other probiotic strains in tackling the deleterious neurobiological effects on exposure to various stress-related conditions can be explored.

A novel cobiotic-based preventive approach against high-fat diet-induced adiposity, nonalcoholic fatty liver and gut derangement in mice.

BACKGROUND: High-fat diets (HFDs) induce systemic inflammation, gut microbial derangements and disturb metabolic homeostasis, resulting in weight gain, insulin resistance and nonalcoholic fatty liver (NAFL). Numerous antioxidants and prebiotic/probiotics per se may prevent HFD-associated comorbidities, but there are no reports related to their combination. OBJECTIVE: In the present study, we aim to evaluate a cobiotic combination of lycopene (antioxidant) and isomalto-oligosaccharides (IMOs, a prebiotic) for prevention of HFD-induced alterations. DESIGN: Male Swiss albino mice were fed either normal pellet diet (NPD) or HFD and lycopene (5 and 10 mg kg(-1)), IMOs (0.5 and 1 g kg(-1)) or their combination for 12 weeks. Systemic adiposity, glucose tolerance, insulin sensitivity, feeding regulators in hypothalamus, hepatosteatosis and liver inflammation, cecal short chain fatty acids (SCFAs), serum inflammatory cytokines, gut morphology and alterations in selected gut microbes were studied. RESULTS: Lycopene, IMOs and their combination prevented weight gain, adiposity, improved adipose tissue fat mobilization and reduced insulin resistance. Hypothalamic orexigenic and anorectic genes have also been modulated by these treatments. Dietary interventions prevented NAFL-like symptoms and improved glucose homeostasis. Improvement in selected gut microbial abundance and SCFA concentration along with reduced systemic inflammation, metabolic endotoxemia and improved ileal and colonic health were observed in mice supplemented with lycopene, IMOs and their combination. Interestingly, cobiotic combination synergistically improved many of the HFD-induced alterations. CONCLUSION: The present work provide evidence that new approach based on cobiotic combination (antioxidant plus prebiotic) can be employed to develop novel class of functional foods for their application against HFD-associated pathological complications.

Possible mechanism involved in sleep deprivation-induced memory dysfunction.

Sleep deprivation disrupts various vital biological and metabolic processes that are necessary for health. The present study was designed to investigate the possible mechanisms of sleep deprivation-induced memory dysfunction by using different behavioral, biochemical and neurochemical parameters. Male Wistar rats were sleep deprived for 72 h using a grid suspended over water. Elevated plus maze, passive avoidance and Morris water maze tests were used to assess memory retention in 72-h sleep-deprived animals. Various electrophysiological (sleep-wake cycle), biochemical (lipid peroxidation, reduced glutathione, nitrite, catalase, acetylcholinesterase) and neurochemical parameters (norepinephrine, dopamine and serotonin) were also assessed. Sleep deprivation resulted in memory dysfunction in all the behavioral paradigms, alteration in the sleep-wake cycle (delayed sleep latency, shortening of rapid eye movement [REM] and non-REM [NREM] sleep and increased waking period) and oxidative stress (increased lipid peroxidation and nitrite levels, depletion of reduced glutathione and catalase activity). In addition, increased levels of acetylcholinesterase (AChE; the enzyme responsible for the degradation of acetylcholine) and reduction in norepinephrine and dopamine levels were seen in 72-h sleep-deprived animals. In conclusion, sleep deprivation-induced memory deficits may possibly be due to the combined effect of oxidative damage and alterations in neurotransmitter levels.

Elevated zero maze: a paradigm to evaluate antianxiety effects of drugs.

Elevated zero maze is a modification of the elevated plus maze model of anxiety in rodents. The novel design comprises an elevated annular platform with two opposite, enclosed quadrants and two open quadrants, removing any ambiguity in the interpretation of the time spent in the central square of the traditional design and allowing uninterrupted exploration. In the present study, we validated elevated zero maze as a tool to study antianxiety activity, using various standard anxiolytics belonging to different pharmacological groups, such as benzodiazepines, barbiturates, alcohol etc., and compared the results with elevated plus maze. Bidirectional sensitivity of the model was also assessed using picrotoxin, pentylenetetrazol and flumazenil, the modulators of GABA(A) and benzodiazepine modulators. Animals were administered different standard antianxiety and anxiogenic drugs, and were allowed to explore the elevated zero maze (time spent in open arm, latency to enter in open arm, total number of entries in open arm and number of stretch attend postures [SAPs]) and elevated plus maze (time spent in open arm, latency to enter in open arm, total number of entries in open arm, first preference of the animal [open/closed] and number of stretchings). Selected drugs and doses were then assessed on the mirror chamber paradigm. Results of the present study indicated that elevated zero maze offered a better animal model to study antianxiety activity, when compared with elevated plus maze and mirror chamber.

Neurochemical changes associated with chronic administration of typical antipsychotics and its relationship with tardive dyskinesia.

The therapeutic success of atypical antipsychotics has focused the attention on the role of receptor systems other than dopaminergic system in the pathophysiology of neuroleptic-associated extrapyramidal side effects such as tardive dyskinesia. In the present study we planned to study time-dependent changes in extracellular levels of norepinephrine, dopamine and serotonin in cortical and subcortical (including striatum) regions of brain and tried to correlate them with hyperkinetic motor activities (vacuous chewing movements [VCMs], tongue protrusions and facial jerking) in rats treated chronically with typical neuroleptics (haloperidol and chlorpromazine). Chronic administration of haloperidol (1 mg/kg) and chlorpromazine (5 mg/kg) resulted in a time-dependent increase in orofacial hyperkinetic movements. There were also significant changes in the extracellular levels of different neurotransmitters in different brain regions (cortical and subcortical regions) as measured by high-performance liquid chromatography/electrochemical detection (HPLC/ED). Both haloperidol and chlorpromazine produced time-dependent decreases in the levels of these neurotransmitters.

U-74500A (lazaroid), a 21-aminosteroid attenuates neuroleptic-induced orofacial dyskinesia.

21-Aminosteroid, or lazaroid, is one of a novel class of antioxidant drugs designed to inhibit iron-dependent lipid peroxidation in biological lipid environments. They have shown promising results in several animal models of traumatic, ischemic and hemorrhagic injury of the central nervous system. Neuroleptic-induced orofacial dyskinesia is an animal model of tardive dyskinesia whose pathophysiology has been related to oxidative stress in the basal ganglia. In this study, we have examined the protective role of U-74500A [pregna-1,4,9(11)-triene-3,20-dione, 21-(4-(5,6-bis(diethylamino)-2-pyridinyl)-1-piperazinyl)-16-ethyl-HCl (16-alpha)], a 21-aminosteroid having antioxidant property in attenuating the behavioral and biochemical effects of chronic haloperidol and chlorpromazine administration. Haloperidol (1 mg/kg/day i.p.) and chlorpromazine (5 mg/kg/day i.p.) administered for 21 days caused a significant increase in vacuous chewing movements (VCMs), tongue protrusion (TP) and the number of facial twitchings (FT) observed on day 22. U-74500A (1, 2 and 5 mg/kg i.p.), administered every day, along with haloperidol (1 mg/kg/day i.p.) and chlorpromazine (5 mg/kg/day), attenuated the increase of VCMs and related behaviors on day 22. Haloperidol and chlorpromazine significantly increased lipid peroxidation in various brain areas such as the cortex, striatum and subcortical parts characterized by an increase in MDA levels. The coadministration of U-74500A limited the effect of haloperidol and chlorpromazine on MDA levels in the cortex and striatum but not in the subcortical parts. U-74500A, an aminosteroid, may have therapeutic use in typical neuroleptic-induced tardive dyskinesia-like effects.

Protective effects of nimesulide (COX Inhibitor), AKBA (5-LOX Inhibitor), and their combination in aging-associated abnormalities in mice.

Several inflammatory processes play a critical role in brain aging and are associated with increased vulnerability to neurodegeneration. Cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX), two enzymes involved in the oxygenation of the arachidonic acid, are upregulated in the central nervous system during aging and are associated with different aging-related brain pathologies. The present experiment was performed to study the effects of 5-LOX inhibitor, acetyl-11-keto-beta-boswellic acid (AKBA), nimesulide (preferential COX-2 inhibitor), and their combination on cognitive performance of young and aged mice, using elevated plus maze test. Chronic administration of AKBA (100 mg/kg, p.o.) and nimesulide (2.42 mg/kg, p.o.) for 15 days significantly reversed the aging-induced retention deficit in mice. Coadministration of AKBA and nimesulide enhanced the cognitive performance in aged mice when compared with that in per se treatment. The aging-related increase in oxidative damage (increased LPO and decreased GSH) was reversed by AKBA, nimesulide, and their combination. Further, per se COX and LOX inhibitors and their combination did not produce any alteration in gastrointestinal parameters; they also reversed the aging-induced motor dysfunction in the aged animals. On the basis of these observations, present findings indicated that the combination of COX and LOX inhibitors (dual inhibitors) may provide a new therapeutic innovation for the treatment of aging-related brain disorders such as Alzheimer's disease and different motor dysfunctions with adequate gastrointestinal tolerability.