Post-traumatic stress disorder (PTSD) is a debilitating neuropsychiatric condition triggered and precipitated by exposure to severe, life-threatening trauma. Emerging evidence implicates the involvement of neuroinflammatory processes in the exacerbation and progression of PTSD. Cordycepin (COR), a natural compound, is reported to alleviate neuroinflammation via downregulating NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasomes. The present study aimed to extrapolate the neuroprotective mechanism of COR against PTSD in mice. Swiss albino mice experienced PTSD-like symptoms due to sequential stressors in first 30 days at critical intervals. Mice exhibiting PTSD-like behaviour were treated with fluoxetine (FLU, 10 mg/kg), an antidepressant drug, and COR (10 and 50 mg/kg). Four behavioural tests were performed in mice to assess the four symptom clusters similar to human PTSD. At the end of the study, immunoassays were performed for serum corticotropin releasing hormone (CRH) and corticosterone (CORT) levels as well as brain neuroinflammation markers including interleukin-6 (IL-6), tumour necrosis factor- α (TNF-α), interleukin-1β (IL-1β) and NLRP3. Behavioural assays demonstrated PTSD-like clusters in mice as observed in clinics. These cluster were associated with elevated levels of brain cytokines IL-6, TNF-α, IL-1β and NLRP3. Dysregulation of hypothalamus-pituitary-adrenal (HPA) axis was evident from significant decline in CORT levels. FLU significantly attenuated the four clusters of PTSD with negative effect on brain cytokines. COR demonstrated a dose-dependent response with 50 mg/kg showing consistent improvement in both behavioural and biochemical parameters. Overall, COR exhibited promising activity in this model and may serve as a potential natural therapeutic strategy to investigate for the management of PTSD in clinics.

The polyphenolic compounds ferulic acid (FA) and p‑coumaric acid (PCA) have been extensively studied for their free radical scavenging and anti‑inflammatory properties. Both compounds are present in food and beverages commonly consumed globally. Our molecular modeling, in‑vitro, and in‑vivo studies suggest that the compounds may be neuroprotective by modulating the nucleotide‑binding domain, leucine‑rich‑containing family, pyrin domain‑containing‑3 (NLRP3) inflammasome pathway. The current study explored the dose‑dependent neuroprotective potential of FA and PCA in a chronic unpredictable mild stress (CUMS) mouse model. Male Swiss albino mice were divided into nine groups consisting of control (CON), CUMS, FA10 (10 mg/kg FA), FA40 (40 mg/kg FA), FA160 (160 mg/kg FA), PCA10 (10 mg/kg PCA), PCA40 (40 mg/kg PCA), PCA160 (160 mg/kg PCA), and FLX (10 mg/kg fluoxetine). All animals, except the CON group, received random mild stressors for 21 days, and from day 22‑42, the treatments were administered alongside the stressors. Behavioral assessments were performed on day 42, followed by sample collection. Brain homogenates from CUMS‑exposed animals expressed elevated levels of the pro‑inflammatory cytokines interleukin (IL)‑1β, IL‑6 and tumor necrosis factor‑alpha (TNF‑α), and oxidative stress markers. Treatment with FA and PCA effectively reduced cytokine release and oxidative stress, alleviating the depressive‑like behavior.

Neuroinflammation contributes to cognitive decline in Alzheimer's disease (AD), and the neurokinin pathway has been implicated in the pathophysiology of AD. Although Substance P (SP), an endogenous ligand to the neurokinin 1 receptor (NK1R), is primarily known as a neurotransmitter, but emerging evidence indicates it has shown both pro and anti-inflammatory actions. However, the dose-dependent nature of the SP-NK1R axis's functional role remains to be fully elucidated. In this study, we examined the effects of SP in a rat model of AD induced by lipopolysaccharide (LPS). A dose of 150 μg/10 μl of LPS was administered through intracerebroventricular injection to induce cognitive impairment in the rats. Two doses of SP, 50 μg/kg and 500 μg/kg were administered intraperitoneally once a day for 21 days. Behavioral assessments included the Morris water maze test and novel object recognition test to investigate cognitive defects, and the open field test evaluated locomotion. Tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), amyloid-beta (Aβ), acetylcholinesterase (AChE), lipid peroxidation, and catalase were estimated in the frontal cortex and hippocampus. The cAMP-responsive element-binding (CREB) protein levels in the whole brain were estimated by western blot. The LPS treatment significantly impaired cognition, increased levels of cytokines, Aβ, oxidative stress, and AChE, while decreasing CREB levels. Notably, the lower dose of SP (50 μg/kg) restored cognitive performance and markers of AD. In contrast, the higher dose of SP (500 μg/kg) failed to reverse spatial memory impairment and neuroinflammation. Thus, our data propose the dose-dependent effect of SP on neuroinflammation-induced cognitive deficits in AD.

Coffee is one of the most frequently consumed beverages worldwide and contains the bioactive constituent caffeine, which is the most commonly consumed psychostimulant. There have been mixed reports of coffee/caffeine’s effects on mood disorders including anxiety and depression. The aim of this study was to evaluate correlations between coffee/caffeine consumption and salivary and plasma biomarkers associated with anxiety and depression in a healthy population. A cross-sectional study design was employed with participants completing a coffee and caffeine consumption questionnaire and providing either morning (n = 55) and/or afternoon (n = 54) saliva samples and/or a plasma sample (n = 39). Biological samples were examined for numerous biomarkers including amylase, prolactin, cortisol (all saliva), caffeine, TBX B2, PGE2, tryptophan and the kynurenine pathway catabolites (all plasma). Weak to moderate inverse or positive correlations between caffeinated coffee consumption and cortisol (R2 = -0.3220; P < 0.05; n = 55), kynurenine (R2 = 0.3878; P < 0.05; n = 39), and kynurenine-to-tryptophan ratio x 100 (R2 = 0.4092; P < 0.05; n = 39), respectively, were identified. Furthermore, positive correlations were identified between caffeine consumption and kynurenine (R2 = 0.3148; P < 0.05; n = 39), kynurenine-to-tryptophan ratio x 100 (R2 = 0.4023; P < 0.05; n = 39), and cortisol (R2 = − 0.2972; P < 0.05; n = 55); and plasma caffeine and kynurenine-to-tryptophan ratio x100 (R2 = 0.4297; P < 0.050; n = 39). The current study provides insights into changes associated with biomarkers induced by the consumption of caffeinated coffee and/or caffeine. Weak to moderate correlations were observed between caffeinated coffee consumption and cortisol, kynurenine, and kynurenine-to-tryptophan ratio. Additionally, weak to moderate correlations we also seen between caffeine and the plasma biomarkers, kynurenine and kynurenine-to-tryptophan ratio.

Schizophrenia is one of the most severe and chronic psychiatric disorders. Over the years, numerous treatment options have been introduced for schizophrenia. Although they are relatively successful in managing the positive symptoms of schizophrenia, most of the current treatments have a negligible effect on the negative and cognitive symptoms. Thus, none of them could prevent the relapse of psychotic episodes. Among the numerous hypotheses explaining the development and progression of schizophrenia, the cytokine hypothesis explains the role of inflammatory markers as a significant culprit in the development of schizophrenia. Elevated cytokines are reported in animal models and schizophrenic patients. The cytokine hypothesis is based on how increased inflammatory markers can cause changes in the dopaminergic, glutamate, and tryptophan metabolism pathways, like that observed in schizophrenic patients. Reasons, such as autoimmune disease, maternal immune activation, infection, etc., can pave the way for the development of schizophrenia and are associated with the negative, positive and cognitive symptoms of schizophrenia. Thus, there is a need to focus on the significance of anti-inflammatory drugs against these symptoms. The development of new treatment strategies in the management of schizophrenia can provide better therapeutic outcomes in terms of the severity of symptoms and treatment of drug-resistant schizophrenia. This review attempts to explain the association between elevated inflammatory markers and various neurotransmitters, and the possible use of medications like nonsteroidal anti-inflammatory drugs, monoclonal antibodies, statins, and estrogens as adjuvant therapy. Over the years, these hypotheses have been the basis for drug discovery for the treatment of schizophrenia. Activated microglia are involved in the pathogenesis of schizophrenia. Inflammatory markers induce IDO and tryptophan dioxygenase to increase KYA. Inflammatory markers influence dopamine and glutamate signalling for psychosis. Inflammatory markers cause glutamate-mediated excitotoxicity and oxidative stress. Anti-inflammatory drugs approach discussed for the management of schizophrenia.

Coffee is a widely consumed beverage that has been shown to have numerous health benefits including positive effects on neurological and psychological conditions including depression. Although positive benefits have been observed, some epidemiological studies have shown that with high consumption of caffeinated coffee, the risk of suicide increases significantly. Therefore, the aim of this study was to investigate the toxicity of key coffee constituents in in vitro neuronal models. The viability of SH-SY5Y neuroblastoma cells was evaluated after 24 h treatment with a range of concentrations (10 µM, 100 µM, and 1000 µM) of caffeine, caffeic acid (CA), chlorogenic acid (CGA), ferulic acid, pyrogallic acid (PA), and trigonelline. Furthermore, specific cell death pathways were investigated for their role in coffee constituent-induced toxicity. It was found that high concentrations (1000 μM) of CA, CGA, and PA were toxic toward undifferentiated SH-SY5Y neuroblastoma cells and caffeine, CA, CGA, and PA toward dibutyryl cyclic AMP differentiated SH-SY5Y neuroblastoma. After mechanisms were investigated cytotoxicity appeared to be due to reactive oxygen species (ROS)-induced apoptosis. This study has shown that high concentrations (1000 μM) of key constituents of coffee were toxic toward both undifferentiated and dibutyryl cyclic AMP differentiated SH-SY5Y cells.

Neuroinflammation mediated by the activation of microglia and subsequent release of proinflammatory cytokines is a key contributor to the pathogenesis of neurodegenerative disorders. In this study, we investigated the neuroprotective effects of p-coumaric acid (PCA) in a lipopolysaccharide (LPS)-induced rat model of neuroinflammation and cognitive impairment. Neuroinflammation was induced by intracerebroventricular (ICV) administration of 150 µg/kg bacterial endotoxin LPS into the fourth ventricle of Sprague–Dawley rats, whereas PCA (160 mg/kg), Donepezil (DON, 5 mg/kg) were administered orally for a period of 14 days, post-LPS administration. PCA has been reported to be active against LPS-induced sickness behavior and chronic unpredictable mild stress models in mice, whereas DON is a centrally acting acetylcholinesterase inhibitor with documented antineuroinflammatory property. Animals were subjected to the Morris Water Maze to assess spatial memory. ICV administration of LPS caused a significant decline in cognitive ability. PCA and DON treatment effectively attenuated this LPS-induced cognitive deficits. In addition to the behavioral improvements, both treatments significantly reduced the central levels of proinflammatory cytokine, interleukin-1β, and lipid peroxidation marker, malondialdehyde levels. Our findings suggest that PCA exerts neuroprotective effects against LPS-induced neuroinflammation and cognitive impairment in rats by plausible modulation of proinflammatory cytokines and oxidative stress pathways.

Treatment-resistant depression (TRD) continues to pose a major challenge in clinical practice, as a large proportion of patients fail to achieve remission despite multiple antidepressant drugs. Growing evidence indicates that dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, together with epigenetic alterations, neuroinflammation, and kynurenine pathway metabolism, plays a central role in the pathophysiology of TRD. Particularly, prolonged stress-induced glucocorticoid receptor (GR) resistance, persistent hypercortisolaemia, and elevated pro-inflammatory cytokines contribute to neurotoxicity, hippocampal atrophy, and impaired neuroplasticity, aggravating depressive symptoms and reducing treatment response. Additionally, dysregulated tryptophan metabolism and the shift towards neurotoxic kynurenine metabolites further impair neuronal function and resulting in TRD. This review integrates recent findings on the complex interplay between HPA axis dysfunction, neuroimmune responses, and metabolic disturbances in TRD while highlighting novel therapeutic avenues such as ketamine, GR modulators, and anti-inflammatory agents. Further, disruption in the blood-brain barrier as one of the mechanisms of TRD was also reviewed. A deeper understanding of these mechanisms will enable the development of personalized treatment strategies to enhance clinical outcomes for TRD patients.

Depression, often stress-induced, is closely related to neuroinflammation, in which microglia, the brain's immune cells, are the leading players. Microglia shift between a quiescent and an active state, promoting both pro- and anti-inflammatory responses. Cannabinoid type 2 (CB2) receptor encoded by the CNR2 gene is a key player to modulate inflammatory activity. CB2 receptor is highly controlled at the epigenetic level, especially in response to stressful stimuli, positioning it between stress, neuroinflammation, and depression. The following review addresses how epigenetic regulation of CNR2 expression affects depression and the dissection, further, of molecular pathways driving neuroinflammation-related depressive states. The present study emphasizes the therapeutic potential of CB2 receptor agonists that selectively interact with activated microglia and opens a new avenue for the treatment of depression associated with neuroinflammation. The review, therefore, provides a framework of underlying mechanisms for developing novel therapeutic strategies that focus on relieving symptoms by modulating the neuroinflammatory response. Finally, this review underlines the possibilities of therapeutic interventions taking into account CB2 receptors in combating depression.

Depression is a complex neurological disease that holds many theories on its aetiology and pathophysiology. The monoamine strategy of treating depression with medications to increase levels of monoamines in the (extra)synapse, primarily through the inhibition of monoamine transporters, does not always work, as seen in patients that lack a response to multiple anti-depressant exposures, as well as a lack of depressive symptoms in healthy volunteers exposed to monoamine reduction. Depression is increasingly being understood not as a single condition, but as a complex interplay of adaptations in various systems, including inflammatory responses and neurotransmission pathways in the brain. This understanding has led to the development of the neurodegenerative hypothesis of depression. This hypothesis, which is gaining widespread acceptance posits that both oxidative stress and inflammation play significant roles in the pathophysiology of depression. This article is a review of the literature focused on neuroinflammation in depression, as well as summarised studies of anti-inflammatory and antioxidant effects of antidepressants.

Autophagy is an abnormal protein degradation and recycling process that is impaired in various neurological diseases like Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease. Spermidine is a natural polyamine found in various plant- and meat-based diets that can induce autophagy and is decreased in various neurodegenerative diseases. It acts on epigenetic enzymes like E1A-binding protein p300, HAT enzymes like Iki3p and Sas3p, and α-tubulin acetyltransferase 1 that modulate autophagy. Histone modifications like acetylation, phosphorylation, and methylation could influence autophagy. Autophagy is epigenetically regulated in various neurodegenerative disorders with many epigenetic enzymes and miRNAs. Polyamine regulation plays an essential role in the disease pathogenesis of AD and PD. Therefore, in this review, we discuss various enzymes and miRNAs involved in the epigenetic regulation of autophagy in neurodegenerative disorders and the role of spermidine as an autophagy enhancer. The alterations in spermidine-mediated regulation of Beclin-1, LC3-II, and p62 genes in AD and other PD-associated enzymes could impact the process of autophagy in these neurodegenerative diseases. With the ever-growing data and such promising effects of spermidine in autophagy, we feel it could be a promising target in this area and worth further detailed studies.

Background: Dopaminergic signaling in the Central Nervous System (CNS) has been observed in the pathophysiology of memory deficits. Rotigotine belongs to a non-ergot-based dopamine receptor agonist possessing anti-inflammatory properties. However, it is uncertain if it has a role in ameliorating cognitive decline. Here, we evaluated the actions of rotigotine on neuroinflammation and memory impairment. Methodology: Rotigotine 1, 3, and 5 mg/kg were administered to mice subcutaneously once a day for fifteen days. Lipopolysaccharide (LPS) 750 µg/kg was administered intraperitoneally for seven days to produce cognitive impairment in mice. Morris water maze and Passive avoidance step-down tests were performed to evaluate memory function. Further, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and amyloid-beta (Aβ) were estimated by ELISA. The mouse brain was analyzed for acetylcholinesterase (AChE) activity, lipid peroxidation, catalase, and reduced glutathione levels. Results: LPS elevated IL-6, Aβ, TNF-α, and AChE activity, promoted oxidative stress, and caused memory decline in mice. Lower doses of rotigotine 1 and 3 mg/kg significantly reduced neuroinflammation, oxidative stress, and AChE activity, followed by improved cognitive impairment. Conclusion: Our data suggest that rotigotine 1 and 3 mg/kg could reverse the neuroinflammation-associated memory impairment.

Neuroinflammation is one of the major pathological factors leading to Alzheimer's disease (AD). The role of microglial cells in neuroinflammation associated with AD has been known for a long time. Recently, astrocytic inflammatory responses have been linked to the neuronal degeneration and pathological development of AD. Lipopolysaccharide (LPS) and Amyloid Beta (Aβ) activate astrocytes and microglial cells via toll-like 4 (TLR4) receptors leading to neuroinflammation. Reactive (activated) astrocytes mainly comprising of A1 astrocytes (A1s) are involved in neuroinflammation, while A2 astrocytes (A2s) possess neuroprotective activity. Studies link low dopamine (DA) levels during the early stages of neurodegenerative disorders with its anti-inflammatory and immuoregulatory properties. DA mediates neuroprotection via inhibition of the A1 astrocytic pathway through blockade of NF-kB and nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3); and promotion of A2 astrocytic pathways leading to the formation of neurotrophic factors like BDNF and GDNF. In this current review, we have discussed the crosstalk between the dopaminergic system in astrocytic TLR4 and NF-kB in addition to NLRP3 inflammasome in the modulation of neuroinflammatory pathologies in cognitive deficits.

Post-traumatic stress disorder (PTSD) is a chronic incapacitating condition with recurrent experience of trauma-related memories, negative mood, altered cognition, and hypervigilance. Agglomeration of preclinical and clinical evidence in recent years specified that alterations in neural networks favor certain characteristics of PTSD. Besides the disruption of hypothalamus-pituitary-axis (HPA) axis, intensified immune status with elevated pro-inflammatory cytokines and arachidonic metabolites of COX-2 such as PGE2 creates a putative scenario in worsening the neurobehavioral facet of PTSD. This review aims to link the Diagnostic and Statistical Manual of mental disorders (DSM-V) symptomology to major neural mechanisms that are supposed to underpin the transition from acute stress reactions to the development of PTSD. Also, to demonstrate how these intertwined processes can be applied to probable early intervention strategies followed by a description of the evidence supporting the proposed mechanisms. Hence in this review, several neural network mechanisms were postulated concerning the HPA axis, COX-2, PGE2, NLRP3, and sirtuins to unravel possible complex neuroinflammatory mechanisms that are obscured in PTSD condition.

Ferulic acid (FA) and p-coumaric acid (PCA) are abundantly present in commonly consumed food and beverages. Being polyphenolic compounds, they have been explored for their antioxidant and anti-inflammatory properties. Based on our previous study, we selected these two compounds to further investigate their potential in lipopolysaccharide (LPS)-induced sickness behavior and the ensuing neuroinflammation by specifically focusing on the NLRP3 inflammasome pathway. Male Swiss albino mice were divided into nine groups (n = 6) consisting of Normal Control, LPS, fluoxetine (FLX), FA40, FA160, FA640, PCA40, PCA160, and PCA640 respectively. Each group received respective FA or PCA treatment except Normal Control and LPS, which received the vehicle, carboxymethylcellulose 0.25% w/v. All groups were challenged with LPS 1.5 mg/kg, intraperitoneally except the Normal Control group, which received saline. Behavioral assessments were performed between 1–2 h, and the whole brains were collected at 3 h post-LPS administration. LPS-induced sickness behavior was characterized by significantly reduced spontaneous activity and high immobility time. The expression of NLRP3, ASC, caspase-1 and IL-1β was significantly increased, along with the levels of brain IL-1β suggesting the assembly and activation of NLRP3 inflammasome pathway. Furthermore, the major cytokines involved in sickness behavior, IL-6 and TNF-α were also significantly elevated with the accompanied lipid peroxidation. The results of this study emphasize that within the employed dose ranges of both FA and PCA, both the compounds were effective at blocking the activation of the NLRP3 inflammasome pathway and thereby reducing the release of IL-1β and the sickness behavior symptoms. There was a prominent effect on cytokine levels and lipid peroxidation as well. Graphical abstract

Alzheimer’s disease (AD), a neurodegenerative condition previously known to affect the older population, is also now seen in younger individuals. AD is often associated with cognitive decline and neuroinflammation elevation primarily due to amyloid β (Aβ) accumulation. Multiple pathological complications in AD call for therapies with a wide range of neuroprotection. Our study aims to evaluate the effect of N-acetyl-L-tryptophan (NAT) in ameliorating the cognitive decline and neuroinflammation induced by Aβ 1-42 oligomers and to determine the therapeutic concentration of NAT in the brain. We administered Aβ 1-42 oligomers in rats via intracerebroventricular (i.c.v.) injection to induce AD-like conditions. The NAT-treated animals lowered the cognitive decline in the Morris water maze characterized by shorter escape latency and increased path efficiency and platform entries. Interestingly, the hippocampus and frontal cortex showed downregulation of tumor necrosis factor, interleukin-6, and substance P levels. NAT treatment also reduced acetylcholinesterase activity and total and phosphorylated nuclear factor kappa B and Tau levels. Lastly, we observed upregulation of cAMP response element-binding protein 1 (CREB1) signaling. Surprisingly, our HPLC method was not sensitive enough to detect the therapeutic levels of NAT in the brain, possibly due to NAT concentrations being below the lowest limit of quantification of our validated method. To summarize, the administration of NAT significantly lowered cognitive decline, neuroinflammatory pathways, and Tau protein and triggered the upregulation of CREB1 signaling, suggesting its neuroprotective role in AD-like conditions.

Objective: Ferulic acid (FA) is a common food ingredient that is abundantly present in various routinely consumed food and beverages. Like many cinnamic acid derivatives, FA produces wide-ranging effects in a dose-dependent manner and various studies link FA consumption with reduced risk of depressive disorders. The aim of this study was to exploit the neuroprotective mechanisms of FA including indoleamine 2,3-dioxygenase (IDO), brain-derived neurotrophic factor (BDNF), and other pro-inflammatory cytokines by employing lipopolysaccharide (LPS)-induced depressive-like behaviour model. Methods: C57BL/6J male mice were divided into 4 groups consisting of saline (SAL), LPS, FA and Imipramine (IMI). Animals were pretreated orally with FA (10 mg/kg) and IMI (10 mg/kg) for 21 days once daily and all groups except SAL were challenged with LPS (0.83 mg/kg) intraperitoneally on day 21. Results: LPS administration produced a biphasic change in the behaviour of the animals where the animals lost a significant weight and express high immobility time at 24 h. Proinflammatory cytokines including, TNF-α, IL-6, IL-1β, and IFN-γ were significantly increased along with increased lipid peroxidation and reduced BDNF. Furthermore, the increased kynurenine to tryptophan ratio was indicative of elevated IDO activity. Conclusion: The results of this study emphasise that low dose of FA is effective in attenuating depressive-like behaviour by modulating IDO, BDNF and reducing neuroinflammation.

In Alzheimer's disease pathology, inhibitors of nuclear factor kappa-beta kinase subunit beta (IKKB) and Tumor necrosis factor receptor 1 (TNFR1) signaling are linked to neuroinflammation-mediated cognitive decline. We explored the role of a phosphodiesterase 5 inhibitor (PDE5I) with dual antagonistic action on IKKB and TNFR1 to inhibit nuclear factor kappa B (NF-kB) and curb neuroinflammation. In the in silico approach, the FDA-approved Zinc 15 library was docked with IKKB and TNFR1. The top compound with dual antagonistic action on IKKB and TNFR1 was selected based on bonding and non-bonding interactions. Further, induced fit docking (IFD), molecular mechanics-generalized Born and surface area (MMGBSA), and molecular dynamic studies were carried out and evaluated. Lipopolysaccharide (LPS) administration caused a neuroinflammation-mediated cognitive decline in mice. Two doses of avanafil were administered for 28 days while LPS was administered for 10 days. Morris water maze (MWM) along with the passive avoidance test (PAT) were carried out. Concurrently brain levels of inflammatory markers, oxidative parameters, amyloid beta (A beta), IKKB and NF-kB levels were estimated. Avanafil produced good IKKB and TNFR1 binding ability. It interacted with crucial inhibitory amino acids of IKKB and TNFR1. MD analysis predicted good stability of avanafil with TNFR1 and IKKB. Avanafil 6 mg/kg could significantly improve performance in MWM, PAT and oxidative parameters and reduce A beta levels and inflammatory markers. As compared to avanafil 3 mg/kg, 6 mg/kg dose was found to exert better efficacy against elevated A beta , neuroinflammatory cytokines and oxidative markers while improving behavioural parameters.Communicated by Ramaswamy H. Sarma

Several neurodegenerative disorders involve impaired neurotransmission, and glutamatergic neurotransmission sets a prototypical example. Glutamate is a predominant excitatory neurotransmitter where the astrocytes play a pivotal role in maintaining the extracellular levels through release and uptake mechanisms. Astrocytes modulate calcium-mediated excitability and release several neurotransmitters and neuromodulators, including glutamate, and significantly modulate neurotransmission. Accumulating evidence supports the concept of excitotoxicity caused by astrocytic glutamatergic release in pathological conditions. Thus, the current review highlights different vesicular and non-vesicular mechanisms of astrocytic glutamate release and their implication in neurodegenerative diseases. As in presynaptic neurons, the vesicular release of astrocytic glutamate is also primarily meditated by calcium-mediated exocytosis. V-ATPase is crucial in the acidification and maintenance of the gradient that facilitates the vesicular storage of glutamate. Along with these, several other components, such as cystine/glutamate antiporter, hemichannels, BEST-1, TREK-1, purinergic receptors and so forth, also contribute to glutamate release under physiological and pathological conditions. Events of hampered glutamate uptake could promote inflamed astrocytes to trigger repetitive release of glutamate. This could be favorable towards the development and worsening of neurodegenerative diseases. Therefore, across neurodegenerative diseases, we review the relations between defective glutamatergic signaling and astrocytic vesicular and non-vesicular events in glutamate homeostasis. The optimum regulation of astrocytic glutamatergic transmission could pave the way for the management of these diseases and add to their therapeutic value.

Objective: Caffeine (CAF) is one of the most commonly consumed nutritional stimulant in beverages. Interestingly, CAF produces varied effects in a dose-dependent manner, and that makes it one of the most controversial nutritional ingredients. Various studies have linked CAF consumption and reduced risk of depressive disorders. The aim of this study was to investigate the effect of CAF on lipopolysaccharide (LPS)-induced neuroinflammation and depressive-like behaviour. Methods: C57BL/6J male mice were divided into four groups consisting of saline (SAL), LPS, CAF and Imipramine (IMI). Animals were pretreated orally with CAF (10 mg/kg) and IMI (10 mg/kg) for 14 days once daily and all groups except SAL were challenged with LPS (0.83 mg/kg) intraperitoneally on day 14. Results: LPS produced a biphasic behavioural response with a significantly high immobility time and weight loss after 24 h. The brain cytokines (TNF-alpha, IL-6, IL-1 beta, and IFN-gamma) levels were remarkably high, along with increased lipid peroxidation and reduced Brain Derived Neurotrophic Factor (BDNF). These biochemical and behavioural changes were significantly alleviated by CAF and IMI chronic treatment. Conclusion: The results of this study implicate that mild-moderate consumption of CAF could impart anti-inflammatory properties under neuroinflammatory conditions by modulating the cytokine and neurotrophic mechanisms.