Creatine increases hippocampal Na+,K+-ATPase activity via NMDA–calcineurin pathway

Effects of tannic acid in streptozotocin-induced sporadic Alzheimer's Disease: insights into memory, redox status, Na+, K+-ATPase and acetylcholinesterase activity

The aim of this study was to investigate the ability of tannic acid (TA) in preventing memory deficits and neurochemical alterations observed in a model for Sporadic Dementia of Alzheimer's Type. Rats were treated with TA (30 mg/kg) daily for 21 days, and subsequently received intracerebroventricular injection of streptozotocin (STZ). We observed that STZ induced learning and memory impairments; however, treatment with TA was able to prevent these effects. In cerebral cortex and hippocampus, STZ induced an increase in acetylcholinesterase activity, reduced Na⁺, K⁺-ATPase activity and induced oxidative stress increasing thiobarbituric acid-reactive substances, nitrites and reactive oxygen species levels and reducing the activity of antioxidant enzymes. Treatment with TA was able in prevent the major of these neurochemical alterations. In conclusion, TA prevented memory deficits, alterations in brain enzyme activities, and oxidative damage induced by STZ. Thus, TA can be an interesting strategy in the prevention of Sporadic Alzheimer's Disease.

A role of Na+, K+ -ATPase in spatial memory deficits and inflammatory/oxidative stress after recurrent concussion in adolescent rats

Sports-related concussions are particularly common during adolescence, and there is insufficient knowledge about how recurrent concussions in this phase of life alter the metabolism of essential structures for memory in adulthood. In this sense, our experimental data revealed that seven recurrent concussions (RC) in 35-day-old rats decreased short-term and long-term memory in the object recognition test (ORT) 30 days after injury. The RC protocol did not alter motor and anxious behavior and the immunoreactivity of brain-derived neurotrophic factor (BDNF) in the cerebral cortex. Recurrent concussions induced the inflammatory/oxidative stress characterized here by increased glial fibrillary acidic protein (GFAP), interleukin 1β (IL 1β), 4-hydroxynonenal (4 HNE), protein carbonyl immunoreactivity, and 2',7'-dichlorofluorescein diacetate oxidation (DCFH) levels and lower total antioxidant capacity (TAC). Inhibited Na⁺,K⁺-ATPase activity (specifically isoform α_2/3) followed by K_m (Michaelis-Menten constant) for increased ATP levels and decreased immunodetection of alpha subunit of this enzyme, suggesting that cognitive impairment after RC is caused by the inability of surviving neurons to maintain ionic gradients in selected targets to inflammatory/oxidative damage, such as Na,K-ATPase activity.

How do stupendous cannabinoids modulate memory processing via affecting neurotransmitter systems?

In the present study, we wanted to review the role of cannabinoids in learning and memory in animal models, with respect to their interaction effects with six principal neurotransmitters involved in learning and memory including dopamine, glutamate, GABA (γ-aminobutyric acid), serotonin, acetylcholine, and noradrenaline. Cannabinoids induce a wide-range of unpredictable effects on cognitive functions, while their mechanisms are not fully understood. Cannabinoids in different brain regions and in interaction with different neurotransmitters, show diverse responses. Previous findings have shown that cannabinoids agonists and antagonists induce various unpredictable effects such as similar effect, paradoxical effect, or dualistic effect. It should not be forgotten that brain neurotransmitter systems can also play unpredictable roles in mediating cognitive functions. Thus, we aimed to review and discuss the effect of cannabinoids in interaction with neurotransmitters on learning and memory. In addition, we mentioned to the type of interactions between cannabinoids and neurotransmitter systems. We suggested that investigating the type of interactions is a critical neuropharmacological issue that should be considered in future studies.

Modulation of Na+/K+- ATPase activity by triterpene 3β, 6β, 16β-trihidroxilup-20 (29)-ene (TTHL) limits the long-term secondary degeneration after traumatic brain injury in mice

Traumatic brain injury (TBI) is a public health problem characterized by a combination of immediate mechanical dysfunction of the brain tissue, and secondary damage. Based on the hypothesis that selected targets, such as Na⁺ K⁺-ATPase are involved in the secondary damage after TBI and modulation of this enzyme activity by triterpene 3β, 6β, 16β-trihidroxilup-20 (29)-ene (TTHL) supports the ethnomedical applications of this plant, we decided to investigate whether previous TTHL treatment interrupts the progression of pathophysiology induced by TBI. Statistical analyses revealed that percussion fluid injury (FPI) increased Na⁺,K⁺-ATPase activity in all isoform (α₁ and α_2/3) 15 min after neuronal injury. The FPI protocol inhibited Na⁺,K⁺-ATPase activity total and α₁ isoform, increased [³H]MK-801 binding but did not alter Dichloro-dihydro-fluorescein diacetate (DCFH-DA) oxidation, carbonylated proteins and free -SH groups 60 min after injury. The increase of immunoreactivity of protein PKC and state of phosphorylation of at Ser¹⁶ of Na⁺,K⁺-ATPase 60 min after FPI suggest the involvement of PKC on Na⁺,K⁺-ATPase activity oscillations characterized by inhibition of total and α₁ isoform. Our experimental data also revealed that natural product rich in compounds such as triterpenes (TTHL; 30 mg/kg) attenuates [³H]MK-801 binding increase, phosphorylation of the PKC and the Na⁺,K⁺-ATPase alpha 1 subunit (Ser¹⁶) induced by FPI. The previous TTHL treatment had not effect on motor disability but protected against spatial memory deficit, BDNF, TrKB expression decrease, protein carbonylation and hippocampal cell death 7 days after FPI. These data suggest that TTHL-induced reduction on initial damage limits the long-term secondary degeneration and supports neural repair or behavioral compensation after neuronal injury.

Southern Brazilian native fruit shows neurochemical, metabolic and behavioral benefits in an animal model of metabolic syndrome

In this work, we evaluated the effects of Psidium cattleianum (Red Type) (PcRT) fruit extract on metabolic, behavioral, and neurochemical parameters in rats fed with a highly palatable diet (HPD) consisted of sucrose (65% carbohydrates being 34% from condensed milk, 8% from sucrose and 23% from starch, 25% protein and 10% fat). Animals were divided into 4 groups: standard chow, standard chow + PcRT extract (200 mg/Kg/day by gavage), HPD, HPD + extract. The animals were treated for 150 days. Concerning chemical profiling, LC/PDA/MS/MS analysis revealed cyanidin-3-O-glucoside as the only anthocyanin in the PcRT extract. Our results showed that the animals exposed to HPD presented glucose intolerance, increased weight gain and visceral fat, as well as higher serum levels of glucose, triacylglycerol, total cholesterol, LDL-cholesterol and interleukin-6. These alterations were prevented by PcRT. In addition, HPD caused an increase in immobility time in a forced swimming test and the fruit extract prevented this alteration, indicating an antidepressant-like effect. PcRT treatment also prevented increased acetylcholinesterase activity in the prefrontal cortex caused by HPD consumption. Moreover, PcRT extract was able to restore Ca²⁺-ATPase activity in the prefrontal cortex, hippocampus, and striatum, as well as Na⁺,K⁺-ATPase activity in the prefrontal cortex and hippocampus. PcRT treatment decreased thiobarbituric acid-reactive substances, nitrite, and reactive oxygen species levels and prevented the reduction of superoxide dismutase activity in all cerebral structures of the HPD group. Additionally, HPD decreased catalase in the hippocampus and striatum. However, the extract prevented this change in the hippocampus. Our results showed that this berry extract has antihyperglycemic and antihyperlipidemic effects, and neuroprotective properties, proving to be a potential therapeutic agent for individuals with metabolic syndrome.

AKAP150 involved in paclitaxel-induced neuropathic pain via inhibiting CN/NFAT2 pathway and downregulating IL-4

Antitubulin chemotherapeutics agents, such as paclitaxel, are effective chemotherapy drugs for cancer treatment. However, painful neuropathy is a major adverse effect limiting the wider application of chemotherapeutics. In this study, we found that A-kinase anchor protein 150 (AKAP150) was significantly upregulated after paclitaxel injection. Inhibition of AKAP150 via siRNA or AKAP150^flox/flox in rodents alleviated the pain behavior induced by paclitaxel, and partly restored the decreased calcineurin (CN) phosphatase activity after paclitaxel treatment. Paclitaxel decreased the expression of anti-inflammatory cytokine interleukin-4 (IL-4), and intrathecal injections of IL-4 effectively alleviated paclitaxel-induced hypersensitivity and the frequency of dorsal root ganglion (DRG) neurons action potential. The decreased CN enzyme activity, resulted in reduced protein expression of nuclear factor of activated T cells 2 (NFAT2) in cell nuclei. Chromatin immunoprecipitation showed that, NFAT2 binds to the IL-4 gene promoter regulating the protein expression of IL-4. Overexpression of NFAT2 by intrathecal injection of the AAV5-NFAT2-GFP virus alleviated the pain behavior induced by paclitaxel via increasing the expression of IL-4. Knocked down AKAP150 by siRNA or AAV5-Cre-GFP partly restored the expression of IL-4 in DRG. Our results indicated that regulation of IL-4 via the CN/NFAT2 pathway mediated by AKAP150 could be a pivotal treatment target for paclitaxel-induced neuropathic pain and or other neuropsychiatric disorders.

Chronic dietary creatine enhances hippocampal-dependent spatial memory, bioenergetics, and levels of plasticity-related proteins associated with NF-κB

The brain has a high demand for energy, of which creatine (Cr) is an important regulator. Studies document neurocognitive benefits of oral Cr in mammals, yet little is known regarding their physiological basis. This study investigated the effects of Cr supplementation (3%, w/w) on hippocampal function in male C57BL/6 mice, including spatial learning and memory in the Morris water maze and oxygen consumption rates from isolated mitochondria in real time. Levels of transcription factors and related proteins (CREB, Egr1, and IκB to indicate NF-κB activity), proteins implicated in cognition (CaMKII, PSD-95, and Egr2), and mitochondrial proteins (electron transport chain Complex I, mitochondrial fission protein Drp1) were probed with Western blotting. Dietary Cr decreased escape latency/time to locate the platform (P < 0.05) and increased the time spent in the target quadrant (P < 0.01) in the Morris water maze. This was accompanied by increased coupled respiration (P < 0.05) in isolated hippocampal mitochondria. Protein levels of CaMKII, PSD-95, and Complex 1 were increased in Cr-fed mice, whereas IκB was decreased. These data demonstrate that dietary supplementation with Cr can improve learning, memory, and mitochondrial function and have important implications for the treatment of diseases affecting memory and energy homeostasis.

Effect of creatine phosphate sodium on bispectral index and recovery quality during the general anaesthesia emergence period in elderly patients: A randomized, double-blind, placebo-controlled trial

Objective

To evaluate the effect of creatine phosphate sodium on bispectral index (BIS) and recovery quality during the general anaesthesia emergence period in elderly patients.

Methods

This randomized, double-blind, placebo-controlled study enrolled patients undergoing transabdominal cholecystectomy under general anaesthesia. Patients were randomly assigned to receive either creatine phosphate sodium (1.0 g/100 ml 0.9% saline; group P) or 100 ml 0.9% saline (group C) over 30 minutes during surgical incision. The BIS values were recorded at anaesthesia induction (T₀), skin incision (T₁), cutting the gallbladder (T₂), suturing the peritoneum (T₃), skin closure (T₄), sputum suction (T₅), extubation (T₆) and 1 min (T₇), 5 min (T₈), 10 min (T₉), and 15 min (T₁₀) after extubation. The anaesthesia duration, operation time, waking time, extubation time, consciousness recovery time, time in the postanaesthesia care unit (PACU), and the Steward recovery scores at T₇, T₈, T₉ and T₁₀ were recorded.

Results

A total of 120 elderly patients were randomized equally to the two groups. Compared with group C, the BIS values were significantly higher in group P at T₅, T₆, T₇ and T₈; and the Steward recovery scores at T₇ and T₈ were significantly higher in group P. The waking time, extubation time, consciousness recovery time and time in the PACU were significantly shorter in group P compared with group C.

Conclusion

Creatine phosphate sodium administered during transabdominal cholecystectomy can improve BIS values and recovery following general anaesthesia in elderly patients.

Metabotropic and ionotropic glutamate receptors as potential targets for the treatment of alcohol use disorder

Emerging evidence indicates that dysfunctional glutamate neurotransmission is critical in the initiation and development of alcohol and drug dependence. Alcohol consumption induced downregulation of glutamate transporter 1 (GLT-1) as reported in previous studies from our laboratory. Glutamate is the major excitatory neurotransmitter in the brain, which acts via interactions with several glutamate receptors. Alcohol consumption interferes with the glutamatergic signal transmission by altering the functions of these receptors. Among the glutamate receptors involved in alcohol-drinking behavior are the metabotropic receptors such as mGluR1/5, mGluR2/3, and mGluR7, as well as the ionotropic receptors, NMDA and AMPA. Preclinical studies using agonists and antagonists implicate these glutamatergic receptors in the development of alcohol use disorder (AUD). Therefore, the purpose of this review is to discuss the neurocircuitry involving glutamate transmission in animals exposed to alcohol and further outline the role of metabotropic and ionotropic receptors in the regulation of alcohol-drinking behavior. This review provides ample information about the potential therapeutic role of glutamatergic receptors for the treatment of AUD.

Astrocytic transporters in Alzheimer's disease

Astrocytes play a fundamental role in maintaining the health and function of the central nervous system. Increasing evidence indicates that astrocytes undergo both cellular and molecular changes at an early stage in neurological diseases, including Alzheimer's disease (AD). These changes may reflect a change from a neuroprotective to a neurotoxic phenotype. Given the lack of current disease-modifying therapies for AD, astrocytes have become an interesting and viable target for therapeutic intervention. The astrocyte transport system covers a diverse array of proteins involved in metabolic support, neurotransmission and synaptic architecture. Therefore, specific targeting of individual transporter families has the potential to suppress neurodegeneration, a characteristic hallmark of AD. A small number of the 400 transporter superfamilies are expressed in astrocytes, with evidence highlighting a fraction of these are implicated in AD. Here, we review the current evidence for six astrocytic transporter subfamilies involved in AD, as reported in both animal and human studies. This review confirms that astrocytes are indeed a viable target, highlights the complexities of studying astrocytes and provides future directives to exploit the potential of astrocytes in tackling AD.

The Influence of Na(+), K(+)-ATPase on Glutamate Signaling in Neurodegenerative Diseases and Senescence

Decreased Na(+), K(+)-ATPase (NKA) activity causes energy deficiency, which is commonly observed in neurodegenerative diseases. The NKA is constituted of three subunits: α, β, and γ, with four distinct isoforms of the catalytic α subunit (α1-4). Genetic mutations in the ATP1A2 gene and ATP1A3 gene, encoding the α2 and α3 subunit isoforms, respectively can cause distinct neurological disorders, concurrent to impaired NKA activity. Within the central nervous system (CNS), the α2 isoform is expressed mostly in glial cells and the α3 isoform is neuron-specific. Mutations in ATP1A2 gene can result in familial hemiplegic migraine (FHM2), while mutations in the ATP1A3 gene can cause Rapid-onset dystonia-Parkinsonism (RDP) and alternating hemiplegia of childhood (AHC), as well as the cerebellar ataxia, areflexia, pescavus, optic atrophy and sensorineural hearing loss (CAPOS) syndrome. Data indicates that the central glutamatergic system is affected by mutations in the α2 isoform, however further investigations are required to establish a connection to mutations in the α3 isoform, especially given the diagnostic confusion and overlap with glutamate transporter disease. The age-related decline in brain α2∕3 activity may arise from changes in the cyclic guanosine monophosphate (cGMP) and cGMP-dependent protein kinase (PKG) pathway. Glutamate, through nitric oxide synthase (NOS), cGMP and PKG, stimulates brain α2∕3 activity, with the glutamatergic N-methyl-D-aspartate (NMDA) receptor cascade able to drive an adaptive, neuroprotective response to inflammatory and challenging stimuli, including amyloid-β. Here we review the NKA, both as an ion pump as well as a receptor that interacts with NMDA, including the role of NKA subunits mutations. Failure of the NKA-associated adaptive response mechanisms may render neurons more susceptible to degeneration over the course of aging.

Creatine as a booster for human brain function. How might it work?

Creatine, a naturally occurring nitrogenous organic acid found in animal tissues, has been found to play key roles in the brain including buffering energy supply, improving mitochondrial efficiency, directly acting as an anti-oxidant and acting as a neuroprotectant. Much of the evidence for these roles has been established in vitro or in pre-clinical studies. Here, we examine the roles of creatine and explore the current status of translation of this research into use in humans and the clinic. Some further possibilities for use of creatine in humans are also discussed.

Creatine supplementation enhances corticomotor excitability and cognitive performance during oxygen deprivation

Impairment or interruption of oxygen supply compromises brain function and plays a role in neurological and neurodegenerative conditions. Creatine is a naturally occurring compound involved in the buffering, transport, and regulation of cellular energy, with the potential to replenish cellular adenosine triphosphate without oxygen. Creatine is also neuroprotective in vitro against anoxic/hypoxic damage. Dietary creatine supplementation has been associated with improved symptoms in neurological disorders defined by impaired neural energy provision. Here we investigate, for the first time in humans, the utility of creatine as a dietary supplement to protect against energetic insult. The aim of this study was to assess the influence of oral creatine supplementation on the neurophysiological and neuropsychological function of healthy young adults during acute oxygen deprivation. Fifteen healthy adults were supplemented with creatine and placebo treatments for 7 d, which increased brain creatine on average by 9.2%. A hypoxic gas mixture (10% oxygen) was administered for 90 min, causing global oxygen deficit and impairing a range of neuropsychological processes. Hypoxia-induced decrements in cognitive performance, specifically attentional capacity, were restored when participants were creatine supplemented, and corticomotor excitability increased. A neuromodulatory effect of creatine via increased energy availability is presumed to be a contributing factor of the restoration, perhaps by supporting the maintenance of appropriate neuronal membrane potentials. Dietary creatine monohydrate supplementation augments neural creatine, increases corticomotor excitability, and prevents the decline in attention that occurs during severe oxygen deficit. This is the first demonstration of creatine's utility as a neuroprotective supplement when cellular energy provision is compromised.