Anatomical correlates for the newly discovered meningeal layer in the existing literature: A systematic review.

The existence of a previously unrecognized subarachnoid lymphatic-like membrane (SLYM) was reported in a recent study. SLYM is described as an intermediate leptomeningeal layer between the arachnoid and pia mater in mouse and human brains, which divides the subarachnoid space (SAS) into two functional compartments. Being a macroscopic structure, having missed detection in previous studies is surprising. We systematically reviewed the published reports in animals and humans to explore whether prior descriptions of this meningeal layer were reported in some way. A comprehensive search was conducted in PubMed/Medline, EMBASE, Google Scholar, Science Direct, and Web of Science databases using combinations of MeSH terms and keywords with Boolean operators from inception until 31 December 2023. We found at least eight studies that provided structural evidence of an intermediate leptomeningeal layer in the brain or spinal cord. However, unequivocal descriptions for this layer all along the central nervous system were scarce. Obscure names like the epipial, intermediate meningeal, outer pial layers, or intermediate lamella were used to describe it. Its microscopic/ultrastructural details closely resemble the recently reported SLYM. We further examined the counterarguments in current literature that are skeptical of the existence of this layer. The potential physiological and clinical implications of this new meningeal layer are significant, underscoring the urgent need for further exploration of its structural and functional details.

Strategies for Treatment of Disease-Associated Dementia Beyond Alzheimer's Disease: An Update.

Memory, cognition, dementia, and neurodegeneration are complexly interlinked processes with various mechanistic pathways, leading to a range of clinical outcomes. They are strongly associated with pathological conditions like Alzheimer's disease, Parkinson's disease, schizophrenia, and stroke and are a growing concern for their timely diagnosis and management. Several cognitionenhancing interventions for management include non-pharmacological interventions like diet, exercise, and physical activity, while pharmacological interventions include medicinal agents, herbal agents, and nutritional supplements. This review critically analyzed and discussed the currently available agents under different drug development phases designed to target the molecular targets, including cholinergic receptor, glutamatergic system, GABAergic targets, glycine site, serotonergic targets, histamine receptors, etc. Understanding memory formation and pathways involved therein aids in opening the new gateways to treating cognitive disorders. However, clinical studies suggest that there is still a dearth of knowledge about the pathological mechanism involved in neurological conditions, making the dropouts of agents from the initial phases of the clinical trial. Hence, a better understanding of the disease biology, mode of drug action, and interlinked mechanistic pathways at a molecular level is required.

Acute Ketamine Facilitates Fear Memory Extinction in a Rat Model of PTSD Along With Restoring Glutamatergic Alterations and Dendritic Atrophy in the Prefrontal Cortex.

Stress represents a major risk factor for psychiatric disorders, including post-traumatic stress disorder (PTSD). Recently, we dissected the destabilizing effects of acute stress on the excitatory glutamate system in the prefrontal cortex (PFC). Here, we assessed the effects of single subanesthetic administration of ketamine (10 mg/kg) on glutamate transmission and dendritic arborization in the PFC of footshock (FS)-stressed rats, along with changes in depressive, anxious, and fear extinction behaviors. We found that ketamine, while inducing a mild increase of glutamate release in the PFC of naïve rats, blocked the acute stress-induced enhancement of glutamate release when administered 24 or 72 h before or 6 h after FS. Accordingly, the treatment with ketamine 6 h after FS also reduced the stress-dependent increase of spontaneous excitatory postsynaptic current (sEPSC) amplitude in prelimbic (PL)-PFC. At the same time, ketamine injection 6 h after FS was found to rescue apical dendritic retraction of pyramidal neurons induced by acute stress in PL-PFC and facilitated contextual fear extinction. These results show rapid effects of ketamine in animals subjected to acute FS, in line with previous studies suggesting a therapeutic action of the drug in PTSD models. Our data are consistent with a mechanism of ketamine involving re-establishment of synaptic homeostasis, through restoration of glutamate release, and structural remodeling of dendrites.

Targeted Delivery of Montelukast for the Treatment of Alzheimer's Disease.

Alzheimer's Disease (AD) is one of the most common neurodegenerative diseases, which affects millions of people worldwide. Accumulation of amyloid-ß plaques and hyperphosphorylated neurofibrillary tangles are the key mechanisms involved in the etiopathogenesis of AD, characterized by memory loss and behavioural changes. Effective therapies targeting AD pathogenesis are limited, making it the largest unmet clinical need. Unfortunately, the available drugs provide symptomatic relief and primary care, with no substantial impact on the disease pathology. However, in recent years researchers are working hard on several potential therapeutic targets to combat disease pathogenesis, and few drugs have also reached clinical trials. In addition, drugs are being repurposed both in the preclinical and clinical studies for the treatment of AD. For instance, montelukast is the most commonly used leukotriene receptor antagonist for treating asthma and seasonal allergy. Its leukotriene antagonistic action can also be beneficial for the reduction of detrimental effects of leukotriene against neuro-inflammation, a hallmark feature of AD. The available marketed formulations of montelukast present challenges such as poor bioavailability and reduced uptake, reflecting the lack of effectiveness of its desired action in the CNS. While on the other side, targeted drug delivery is a satisfactory approach to surpass the challenges associated with the therapeutic agents. This review will discuss the enhancement of montelukast treatment efficacy and its access to CNS by using new approaches like nano-formulation, nasal gel, solid lipid formulation, nano-structure lipid carrier (NSLC), highlighting lessons learned to target AD pathologies and hurdles that persist.

Metabolic Stress and Inflammation: Implication in Treatment for Neurological Disorders.

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Combined and individual strategy of exercise generated preconditioning and low dose copper nanoparticles serve as superlative approach to ameliorate ISO-induced myocardial infarction in rats.

BACKGROUND: Myocardial infarction (MI) is a solitary fatal condition with towering prevalence of mortality worldwide. Our previous study reports that low-dose copper nanoparticles (CuNP) can halt the progression of diabetes-induced cardiotoxicity as copper has anti-inflammatory, anti-proliferative and anti-oxidant potential. In addition, exercise training has also been considered a hallmark for cardiac health. METHOD: Cardioprotective potential of CuNP (1mg/kg/day, po, 4 weeks) and exercise (swimming, 90min, 5days/4 weeks) either alone or in combination was estimated by measuring the surge in serum nitrite/nitrate concentration and reduction in creatine kinase MB (CKMB), lactate dehydrogenase (LDH), cardiac troponin I (cTnI), lipid profile, oxidative stress, structural abnormalities against isproterenol (ISO)-induced MI. RESULTS: ISO significantly increased CKMB, LDH, cTnI, lipid alteration, oxidative stress, structural abnormalities and decrease nitrite/nitrate concentration in serum. Quantitative estimation of total and phosphorylated Akt(SER-473)/GSK-3b(SER-9) indicated the significant reduction in pAkt and pGSK-3b in ISO treated animal. Individual and combined treatment of CuNP and exercise significantly reduce ISO -induced CKMB, cTnI, LDH, and improve nitrite/nitrate concentration and lipid profile. Attenuation of myocardial oxidative stress and serum TBARS revealed the associated preconditioning effect of exercise and CuNP against oxidative stress. Exercise and CuNP also showed the protective potential against structural abnormalities. However, the cardioprotective effect of individual and combined strategy of exercise and CuNP was vanished by wortmannin and also avoid the downregulation of pGSK-3b. CONCLUSION: Low-dose CuNP and exercise training significantly prevents ISO-induced MI through preconditioning and GSK-3b inhibition. Ability to upsurge the NO level, lipid profile and reduced oxidative stress improve the potency of combined strategy.

Exercise preconditioning and low dose copper nanoparticles exhibits cardioprotection through targeting GSK-3ß phosphorylation in ischemia/reperfusion induced myocardial infarction.

BACKGROUND: Drinking water from copper vessels and aerobic exercise have been the known facts for cardioprotection. Our previous report explored the significant cardioprotective potential of copper and exercise training by increasing phosphorylation of GSK-3ß and anti-oxidant potential. OBJECTIVE: Present study focuses the therapeutic potential of CuNP and exercise training through their molecular interaction with GSK-3ß, inflammatory cytokinin, oxidative stress and necrosis. METHODS: The Myocardial damage was assessed by estimating the serum nitrite/nitrate concentration, increased CKMB, LDH, cTnI level, oxidative stress, inflammatory cytokinin and structural abnormalities in I/R insulted rats. Expression of Akt/pAkt and GSK-3ß/pGSK-3ß was measured by western blotting. RESULT: Treatment with CuNP (1 mg/kg/day, p.o., 4 weeks) and exercise training (swimming, 90 min/4 weeks) either alone or in combination markedly reduced I/R induced myocardial damage by attenuating biochemical and structural alteration. A significant reduction in oxidative stress and inflammatory mediators were observed in CuNP and exercise training treatment against I/R insulted rats. Moreover, improved serum NO bioavailability was observed in CuNP and exercise treated rats. Wortmannin associated blockage of cardioprotection induced by CuNP and exercise training and up-regulation of pAkt and pGSK-3ß in I/R insulted heart confirmed the GSK-3ß phosphorylation potential of CuNP and exercise training and -associated cardioprotection. CONCLUSION: Treatment with CuNP and exercise training either alone or in combination favourably phosphorylate GSK-3ß kinase pathways and further diminish oxidative stress, inflammatory cytokines, apoptosis and increase serum bioavailability of NO in the I/R insulted rats which tends to protect myocardial damage.

The malleable brain: plasticity of neural circuits and behavior - a review from students to students.

One of the most intriguing features of the brain is its ability to be malleable, allowing it to adapt continually to changes in the environment. Specific neuronal activity patterns drive long-lasting increases or decreases in the strength of synaptic connections, referred to as long-term potentiation and long-term depression, respectively. Such phenomena have been described in a variety of model organisms, which are used to study molecular, structural, and functional aspects of synaptic plasticity. This review originated from the first International Society for Neurochemistry (ISN) and Journal of Neurochemistry (JNC) Flagship School held in Alpbach, Austria (Sep 2016), and will use its curriculum and discussions as a framework to review some of the current knowledge in the field of synaptic plasticity. First, we describe the role of plasticity during development and the persistent changes of neural circuitry occurring when sensory input is altered during critical developmental stages. We then outline the signaling cascades resulting in the synthesis of new plasticity-related proteins, which ultimately enable sustained changes in synaptic strength. Going beyond the traditional understanding of synaptic plasticity conceptualized by long-term potentiation and long-term depression, we discuss system-wide modifications and recently unveiled homeostatic mechanisms, such as synaptic scaling. Finally, we describe the neural circuits and synaptic plasticity mechanisms driving associative memory and motor learning. Evidence summarized in this review provides a current view of synaptic plasticity in its various forms, offers new insights into the underlying mechanisms and behavioral relevance, and provides directions for future research in the field of synaptic plasticity. Read the Editorial Highlight for this article on page 788. Cover Image for this issue: doi: 10.1111/jnc.13815.

Parthenolide, an NF-κB Inhibitor Ameliorates Diabetes-Induced Behavioural Deficit, Neurotransmitter Imbalance and Neuroinflammation in Type 2 Diabetes Rat Model.

Diabetes is associated with behavioural and neurochemical alterations. In this manuscript, we are reporting the beneficial effects of parthenolide, an NF-κB inhibitor on behavioural and neurochemical deficits in type 2 diabetic rat model. Diabetes was induced by high-fat diet followed by low dose of streptozotocin (35 mg/kg). Elevated plus maze, open-field, MWM and passive avoidance test paradigm were used to assess behavioural and cognitive deficits. Three-week treatment of parthenolide (0.25 and 0.50 mg/kg; i.p.) attenuated diabetes-induced alteration in cognitive function in Morris water maze and passive avoidance test. Anxiety-like behaviour was also reduced by parthenolide treatment. Moreover, TNF-α and IL-6 levels were significantly decreased in cortex and hippocampus of parthenolide-treated rats. Three-week parthenolide treatment also toned down the alteration of GABA and glutamate homoeostasis. Results of this study corroborate the involvement of neuroinflammation in the development of behavioural and neurochemical deficits in diabetic animals and point towards the therapeutic potential of parthenolide in diabetes-induced alteration of learning, memory and anxiety behaviour.

Refolded Recombinant Human Paraoxonase 1 Variant Exhibits Prophylactic Activity Against Organophosphate Poisoning.

Organophosphate (OP) compounds are neurotoxic chemicals, and current treatments available for OP-poisoning are considered as unsatisfactory and inadequate. There is an urgent need for the development of more effective treatment(s) for OP-poisoning. Human paraoxonase 1 (h-PON1) is known to hydrolyze a variety of OP-compounds and is a leading candidate for the development of prophylactic and therapeutic agent against OP-poisoning in humans. Non-availability of effective system(s) for the production of recombinant h-PON1 (rh-PON1) makes it hard to produce improved variant(s) of this enzyme and analyze their in vivo efficacy in animal models. Production of recombinant h-PON1 (rh-PON1) using an Escherichia coli expression system is a key to develop variant(s) of h-PON1. Recently, we have developed a procedure to produce active rh-PON1 enzymes by using E. coli expression system. In this study, we have characterized the OP-hydrolyzing properties of refolded rh-PON1(wt) and rh-PON1(H115W;R192K) variant. Our results show that refolded rh-PON1(H115W;R192K) variant exhibit enhanced OP-hydrolyzing activity in in vitro and ex vivo assays and exhibited prophylactic activity in mouse model of OP-poisoning, suggesting that refolded rh-PON1 can be developed as a therapeutic candidate.