Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 95
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Int J Mol Sci ; 24(7)2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-37047062

RESUMO

Cerebellar ataxia is a neurodegenerative disorder with no definitive treatment. Although previous study demonstrated the neuroprotective effects of Hericium erinaceus (H.E.), the mechanisms of H.E. treatment on the neuroinflammatory response, neurotransmission, and related metabolites remain largely unknown. We demonstrated that 3-AP rats treated with 25 mg/kg H.E. extracts had improved motor coordination and balance in the accelerated rotarod and rod tests. We showed that the H.E. treatment upregulated the expression of Tgfb1, Tgfb2, and Smad3 genes to levels comparable to those in the non-3-AP control group. Interestingly, we also observed a significant correlation between Tgfb2 gene expression and rod test performance in the 3-AP saline group, but not in the non-3-AP control or H.E.+3-AP groups, indicating a relationship between Tgfb2 gene expression and motor balance in the 3-AP rat model. Additionally, we also found that the H.E. treatment increased mitochondrial COX-IV protein expression and normalized dopamine-serotonin neurotransmission and metabolite levels in the cerebellum of the H.E.+3-AP group compared to the 3-AP saline group. In conclusion, our findings suggest that the H.E. treatment improved motor function in the 3-AP rat model, which was potentially mediated through neuroprotective mechanisms involving TGFB2-Smad3 signaling via normalization of neurotransmission and metabolic pathways.


Assuntos
Ataxia Cerebelar , Ratos , Animais , Ataxia Cerebelar/tratamento farmacológico , Ataxia Cerebelar/genética , Ataxia Cerebelar/metabolismo , Hericium , Modelos Animais de Doenças , Anti-Inflamatórios/uso terapêutico
2.
Aging Dis ; 14(1): 112-135, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36818556

RESUMO

Declining global DNA methylation and cognitive impairment are reported to occur in the normal aging process. It is not known if DNA methylation plays a role in the efficacy of memory-enhancing therapies. In this study, aged animals were administered prelimbic cortical deep brain stimulation (PrL DBS) and/or L-methionine (MET) treatment. We found that PrL DBS and MET (MET-PrL DBS) co-administration resulted in hippocampal-dependent spatial memory enhancements in aged animals. Molecular data suggested MET-PrL DBS induced DNA methyltransferase DNMT3a-dependent methylation, robust synergistic upregulation of neuroplasticity-related genes, and simultaneous inhibition of the memory-suppressing gene calcineurin in the hippocampus. We further found that MET-PrL DBS also activated the PKA-CaMKIIα-BDNF pathway, increased hippocampal neurogenesis, and enhanced dopaminergic and serotonergic neurotransmission. We next inhibited the activity of DNA methyltransferase (DNMT) by RG108 infusion in the hippocampus of young animals to establish a causal relationship between DNMT activity and the effects of PrL DBS. Hippocampal DNMT inhibition in young animals was sufficient to recapitulate the behavioral deficits observed in aged animals and abolished the memory-enhancing and molecular effects of PrL DBS. Our findings implicate hippocampal DNMT as a therapeutic target for PrL DBS and pave way for the potential use of non-invasive neuromodulation modalities against dementia.

3.
Front Aging Neurosci ; 14: 964336, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35966777

RESUMO

Alzheimer's disease (AD) is the most common form of dementia. Although previous studies have selectively investigated the localization of amyloid-beta (Aß) deposition in certain brain regions, a comprehensive characterization of the rostro-caudal distribution of Aß plaques in the brain and their inter-regional correlation remain unexplored. Our results demonstrated remarkable working and spatial memory deficits in 9-month-old 5xFAD mice compared to wildtype mice. High Aß plaque load was detected in the somatosensory cortex, piriform cortex, thalamus, and dorsal/ventral hippocampus; moderate levels of Aß plaques were observed in the motor cortex, orbital cortex, visual cortex, and retrosplenial dysgranular cortex; and low levels of Aß plaques were located in the amygdala, and the cerebellum; but no Aß plaques were found in the hypothalamus, raphe nuclei, vestibular nucleus, and cuneate nucleus. Interestingly, the deposition of Aß plaques was positively associated with brain inter-regions including the prefrontal cortex, somatosensory cortex, medial amygdala, thalamus, and the hippocampus. In conclusion, this study provides a comprehensive morphological profile of Aß deposition in the brain and its inter-regional correlation. This suggests an association between Aß plaque deposition and specific brain regions in AD pathogenesis.

4.
Cells ; 11(15)2022 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-35892581

RESUMO

Alzheimer's disease (AD) is a neurodegenerative disorder, and no effective treatments are available to treat this disorder. Therefore, researchers have been investigating Hericium erinaceus, or the monkey head mushroom, an edible medicinal mushroom, as a possible treatment for AD. In this narrative review, we evaluated six preclinical and three clinical studies of the therapeutic effects of Hericium erinaceus on AD. Preclinical trials have successfully demonstrated that extracts and bioactive compounds of Hericium erinaceus have potential beneficial effects in ameliorating cognitive functioning and behavioral deficits in animal models of AD. A limited number of clinical studies have been conducted and several clinical trials are ongoing, which have thus far shown analogous outcomes to the preclinical studies. Nonetheless, future research on Hericium erinaceus needs to focus on elucidating the specific neuroprotective mechanisms and the target sites in AD. Additionally, standardized treatment parameters and universal regulatory systems need to be established to further ensure treatment safety and efficacy. In conclusion, Hericium erinaceus has therapeutic potential and may facilitate memory enhancement in patients with AD.


Assuntos
Doença de Alzheimer , Hericium , Memória , Doença de Alzheimer/tratamento farmacológico , Animais , Extratos Celulares/farmacologia , Extratos Celulares/uso terapêutico , Modelos Animais de Doenças , Hericium/química , Humanos , Memória/efeitos dos fármacos , Neuroproteção/efeitos dos fármacos
5.
Brain Res Bull ; 188: 92-107, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35853529

RESUMO

The 'neurogenesis hypothesis of depression' emphasizes the importance of upregulated hippocampal neurogenesis for the efficacy of antidepressant treatment. Neuromodulation is a promising therapeutic method that stimulates neural circuitries to treat neuropsychiatric illnesses. We conducted a scoping review on the neurogenic and antidepressant outcomes of neuromodulation in animal models of depression. PubMed, Web of Science, and PsycInfo were comprehensively searched for full-text English articles from inception to October 5, 2021. Data screening and extraction were conducted independently by two researchers. Seventeen eligible studies were included in this review. The majority of studies used non-invasive neuromodulation (n = 14) and assessed neurogenesis using neural proliferation (n = 16) and differentiation markers (n = 9). Limited reports (n = 2) used neurogenic inhibitors to evaluate the role of neurogenesis on the depressive-like behavioral outcomes. Overall, neuromodulation substantially effectuated both hippocampal cell proliferation and antidepressant-like behavior in animal models of depression, with some providing evidence for enhanced neuronal differentiation and maturation. The proposed neurogenic-related mechanisms mediating the neuromodulation efficacies included neurotrophic processes, anti-apoptotic pathways, and normalization of HPA axis functions. Further research is warranted to explore the role of neuromodulation-induced neurogenic effects on treatment efficacies and to elucidate the underlying molecular mechanisms.


Assuntos
Depressão , Sistema Hipotálamo-Hipofisário , Animais , Antidepressivos/metabolismo , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Depressão/tratamento farmacológico , Hipocampo/metabolismo , Neurogênese/fisiologia , Sistema Hipófise-Suprarrenal
6.
Brain Stimul ; 15(3): 843-856, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35640844

RESUMO

BACKGROUND: Given that visual impairment is bi-directionally associated with depression, we examined whether transcorneal electrical stimulation (TES), a non-invasive treatment for visual disorders, can ameliorate depressive symptoms. OBJECTIVE: The putative antidepressant-like effects of TES and the underlying mechanisms were investigated in an S334ter-line-3 rat model of retinal degeneration and a rat model of chronic unpredictable stress (CUS). METHODS: TES was administered daily for 1 week in S334ter-line-3 and CUS rats. The effects of TES on behavioral parameters, plasma corticosterone levels, and different aspects of neuroplasticity, including neurogenesis, synaptic plasticity, and apoptosis, were examined. RESULTS: In S334ter-line-3 rats, TES induced anxiolytic and antidepressant-like behaviors in the cylinder, open field, home cage emergence, and forced swim tests. In the CUS rat model, TES induced hedonic-like behavior and decreased behavioral despair, which were accompanied by reduced plasma corticosterone levels and upregulated expression of neurogenesis-related genes. Treatment with the neurogenesis blocker temozolomide only inhibited the hedonic-like effect of TES, suggesting the antidepressant-like effects of TES were mediated through both neurogenesis-dependent and -independent mechanisms. Furthermore, TES was found to normalize the protein expression of synaptic markers and apoptotic Bcl-2-associated X protein in the hippocampus and amygdala in the CUS rat model. The improvements in neuroplasticity may involve protein kinase B (AKT) and protein kinase A (PKA) signaling pathways in the hippocampus and amygdala, respectively, as demonstrated by the altered pAKT/AKT and pPKA/PKA ratios. CONCLUSION: The overall findings suggest a possible neuroplasticity mechanism of the antidepressant-like effects of TES.


Assuntos
Corticosterona , Proteínas Proto-Oncogênicas c-akt , Animais , Antidepressivos/farmacologia , Corticosterona/metabolismo , Corticosterona/farmacologia , Depressão/metabolismo , Depressão/terapia , Modelos Animais de Doenças , Estimulação Elétrica , Hipocampo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-akt/farmacologia , Ratos , Ratos Sprague-Dawley , Estresse Psicológico/complicações , Estresse Psicológico/terapia
7.
Front Neuroendocrinol ; 65: 100986, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35167824

RESUMO

Melatonin and novel melatonin-based therapies such as melatonin-containing hybrid molecules, melatonin analogues, and melatonin derivatives have been investigated as potential therapeutics against Alzheimer's disease (AD) pathogenesis. In this review, we examine the developmental trends of melatonin therapies for AD from 1997 to 2021. We then highlight the neuroprotective mechanisms of melatonin therapy derived from preclinical studies. These mechanisms include the alleviation of amyloid-related burden, neurofibrillary tangle accumulation, oxidative stress, neuroinflammation, apoptosis, mitochondrial dysfunction, and impaired neuroplasticity and neurotransmission. We further illustrate the beneficial effects of melatonin on behavior in animal models of AD. Next, we discuss the clinical effects of melatonin on sleep, cognition, behavior, psychiatric symptoms, electroencephalography findings, and molecular biomarkers in patients with mild cognitive impairment and AD. We then explore the effectiveness of novel melatonin-based therapies. Lastly, we discuss the limitations of current melatonin therapies for AD and suggest two emerging research themes for future study.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Melatonina , Animais , Disfunção Cognitiva/tratamento farmacológico , Humanos , Melatonina/farmacologia , Melatonina/uso terapêutico , Plasticidade Neuronal , Sono
8.
Chin Med ; 16(1): 132, 2021 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-34876186

RESUMO

BACKGROUND: Depression is a severe neuropsychiatric disorder that affects more than 264 million people worldwide. The efficacy of conventional antidepressants are barely adequate and many have side effects. Hericium erinaceus (HE) is a medicinal mushroom that has been reported to have therapeutic potential for treating depression. METHODS: Animals subjected to chronic restraint stress were given 4 weeks HE treatment. Animals were then screened for anxiety and depressive-like behaviours. Gene and protein assays, as well as histological analysis were performed to probe the role of neurogenesis in mediating the therapeutic effect of HE. Temozolomide was administered to validate the neurogenesis-dependent mechanism of HE. RESULTS: The results showed that 4 weeks of HE treatment ameliorated depressive-like behaviours in mice subjected to 14 days of restraint stress. Further molecular assays demonstrated the 4-week HE treatment elevated the expression of several neurogenesis-related genes and proteins, including doublecortin, nestin, synaptophysin, brain-derived neurotrophic factor (BDNF), tropomyosin receptor kinase B (TrkB), phosphorylated extracellular signal-regulated kinase, and phosphorylated cAMP response element-binding protein (pCREB). Increased bromodeoxyuridine-positive cells were also observed in the dentate gyrus of the hippocampus, indicating enhanced neurogenesis. Neurogenesis blocker temozolomide completely abolished the antidepressant-like effects of HE, confirming a neurogenesis-dependent mechanism. Moreover, HE induced anti-neuroinflammatory effects through reducing astrocyte activation in the hippocampus, which was also abolished with temozolomide administration. CONCLUSION: HE exerts antidepressant effects by promoting neurogenesis and reducing neuroinflammation through enhancing the BDNF-TrkB-CREB signalling pathway.

9.
Int J Mol Sci ; 22(18)2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34576314

RESUMO

Alzheimer's disease (AD) is a progressive debilitating neurodegenerative disease and the most common form of dementia in the older population. At present, there is no definitive effective treatment for AD. Therefore, researchers are now looking at stem cell therapy as a possible treatment for AD, but whether stem cells are safe and effective in humans is still not clear. In this narrative review, we discuss both preclinical studies and clinical trials on the therapeutic potential of human stem cells in AD. Preclinical studies have successfully differentiated stem cells into neurons in vitro, indicating the potential viability of stem cell therapy in neurodegenerative diseases. Preclinical studies have also shown that stem cell therapy is safe and effective in improving cognitive performance in animal models, as demonstrated in the Morris water maze test and novel object recognition test. Although few clinical trials have been completed and many trials are still in phase I and II, the initial results confirm the outcomes of the preclinical studies. However, limitations like rejection, tumorigenicity, and ethical issues are still barriers to the advancement of stem cell therapy. In conclusion, the use of stem cells in the treatment of AD shows promise in terms of effectiveness and safety.


Assuntos
Doença de Alzheimer/terapia , Animais , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Mesenquimais/metabolismo , Doenças Neurodegenerativas/terapia , Transplante de Células-Tronco
10.
Int J Mol Sci ; 22(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202125

RESUMO

Alzheimer's disease is a neurodegenerative disorder associated with age, and is characterized by pathological markers such as amyloid-beta plaques and neurofibrillary tangles. Symptoms of AD include cognitive impairments, anxiety and depression. It has also been shown that individuals with AD have impaired neurotransmission, which may result from the accumulation of amyloid plaques and neurofibrillary tangles. Preclinical studies showed that melatonin, a monoaminergic neurotransmitter released from the pineal gland, is able to ameliorate AD pathologies and restore cognitive impairments. Theoretically, inhibition of the pathological progression of AD by melatonin treatment should also restore the impaired neurotransmission. This review aims to explore the impact of AD on neurotransmission, and whether and how melatonin can enhance neurotransmission via improving AD pathology.


Assuntos
Doença de Alzheimer/metabolismo , Melatonina/metabolismo , Neurotransmissores/metabolismo , Transmissão Sináptica , Doença de Alzheimer/etiologia , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Monoaminas Biogênicas/metabolismo , Suscetibilidade a Doenças , Humanos , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Fosforilação , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Proteínas tau/metabolismo
11.
Aging Dis ; 11(5): 1235-1259, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33014535

RESUMO

Alzheimer's disease (AD) is the most common neurodegenerative disorder worldwide and causes severe financial and social burdens. Despite much research on the pathogenesis of AD, the neuropathological mechanisms remain obscure and current treatments have proven ineffective. In the past decades, transgenic rodent models have been used to try to unravel this disease, which is crucial for early diagnosis and the assessment of disease-modifying compounds. In this review, we focus on transgenic rodent models used to study amyloid-beta pathology in AD. We also discuss their possible use as promising tools for AD research. There is still no effective treatment for AD and the development of potent therapeutics are urgently needed. Many molecular pathways are susceptible to AD, ranging from neuroinflammation, immune response, and neuroplasticity to neurotrophic factors. Studying these pathways may shed light on AD pathophysiology as well as provide potential targets for the development of more effective treatments. This review discusses the advantages and limitations of these models and their potential therapeutic implications for AD.

12.
Aging Dis ; 11(5): 1291-1316, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33014538

RESUMO

Besides extracellular deposition of amyloid beta and formation of phosphorylated tau in the brains of patients with Alzheimer's disease (AD), the pathogenesis of AD is also thought to involve mitochondrial dysfunctions and altered neurotransmission systems. However, none of these components can describe the diverse cognitive, behavioural, and psychiatric symptoms of AD without the pathologies interacting with one another. The purpose of this review is to understand the relationships between mitochondrial and neurotransmission dysfunctions in terms of (1) how mitochondrial alterations affect cholinergic and monoaminergic systems via disruption of energy metabolism, oxidative stress, and apoptosis; and (2) how different neurotransmission systems drive mitochondrial dysfunction via increasing amyloid beta internalisation, oxidative stress, disruption of mitochondrial permeabilisation, and mitochondrial trafficking. All these interactions are separately discussed in terms of neurotransmission systems. The association of mitochondrial dysfunctions with alterations in dopamine, norepinephrine, and histamine is the prospective goal in this research field. By unfolding the complex interactions surrounding mitochondrial dysfunction in AD, we can better develop potential treatments to delay, prevent, or cure this devastating disease.

13.
J Clin Med ; 9(10)2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33053848

RESUMO

Major depression contributes significantly to the global disability burden. Since the first clinical study of deep brain stimulation (DBS), over 406 patients with depression have now undergone this neuromodulation therapy, and 30 animal studies have investigated the efficacy of subgenual cingulate DBS for depression. In this review, we aim to provide a comprehensive overview of the progress of DBS of the subcallosal cingulate in humans and the medial prefrontal cortex, its rodent homolog. For preclinical animal studies, we discuss the various antidepressant-like behaviors induced by medial prefrontal cortex DBS and examine the possible mechanisms including neuroplasticity-dependent/independent cellular and molecular changes. Interestingly, the response rate of subcallosal cingulate Deep brain stimulation marks a milestone in the treatment of depression. DBS among patients with treatment-resistant depression was estimated to be approximately 54% across clinical studies. Although some studies showed its stimulation efficacy was limited, it still holds great promise as a therapy for patients with treatment-resistant depression. Overall, further research is still needed, including more credible clinical research, preclinical mechanistic studies, precise selection of patients, and customized electrical stimulation paradigms.

14.
Sci Rep ; 10(1): 14945, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32913245

RESUMO

Cerebellar ataxia is a neurodegenerative disorder with no definitive treatment. Although several studies have demonstrated the neuroprotective effects of Hericium erinaceus (H.E.), its mechanisms in cerebellar ataxia remain largely unknown. Here, we investigated the neuroprotective effects of H.E. treatment in an animal model of 3-acetylpyridine (3-AP)-induced cerebellar ataxia. Animals administered 3-AP injection exhibited remarkable impairments in motor coordination and balance. There were no significant effects of 25 mg/kg H.E. on the 3-AP treatment group compared to the 3-AP saline group. Interestingly, there was also no significant difference in the 3-AP treatment group compared to the non-3-AP control, indicating a potential rescue of motor deficits. Our results revealed that 25 mg/kg H.E. normalised the neuroplasticity-related gene expression to the level of non-3-AP control. These findings were further supported by increased protein expressions of pERK1/2-pCREB-PSD95 as well as neuroprotective effects on cerebellar Purkinje cells in the 3-AP treatment group compared to the 3-AP saline group. In conclusion, our findings suggest that H.E. potentially rescued behavioural motor deficits through the neuroprotective mechanisms of ERK-CREB-PSD95 in an animal model of 3-AP-induced cerebellar ataxia.


Assuntos
Comportamento Animal/efeitos dos fármacos , Ataxia Cerebelar/tratamento farmacológico , Hericium/crescimento & desenvolvimento , Transtornos Motores/prevenção & controle , Fármacos Neuroprotetores/farmacologia , Neurotoxinas/toxicidade , Piridinas/toxicidade , Animais , Ataxia Cerebelar/induzido quimicamente , Ataxia Cerebelar/psicologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Modelos Animais de Doenças , Proteína 4 Homóloga a Disks-Large/genética , Proteína 4 Homóloga a Disks-Large/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Hericium/química , Masculino , Transtornos Motores/genética , Transtornos Motores/metabolismo , Transtornos Motores/patologia , Células de Purkinje/efeitos dos fármacos , Células de Purkinje/patologia , Ratos , Ratos Sprague-Dawley
15.
FASEB J ; 34(11): 14588-14601, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32910512

RESUMO

Mitochondrial bioenergetics is dynamically coupled with neuronal activities, which are altered by hypoxia-induced respiratory neuroplasticity. Here we report structural features of postsynaptic mitochondria in the pre-Bötzinger complex (pre-BötC) of rats treated with chronic intermittent hypoxia (CIH) simulating a severe condition of obstructive sleep apnea. The subcellular changes in dendritic mitochondria and histochemistry of cytochrome c oxidase (CO) activity were examined in pre-BötC neurons localized by immunoreactivity of neurokinin 1 receptors. Assays of mitochondrial electron transport chain (ETC) complex I, IV, V activities, and membrane potential were performed in the ventrolateral medulla containing the pre-BötC region. We found significant decreases in the mean length and area of dendritic mitochondria in the pre-BötC of CIH rats, when compared to the normoxic control and hypoxic group with daily acute intermittent hypoxia (dAIH) that evokes robust synaptic plasticity. Notably, these morphological alterations were mainly observed in the mitochondria in close proximity to the synapses. In addition, the proportion of mitochondria presented with enlarged compartments and filamentous cytoskeletal elements in the CIH group was less than the control and dAIH groups. Intriguingly, these distinct characteristics of structural adaptability were observed in the mitochondria within spatially restricted dendritic spines. Furthermore, the proportion of moderately to darkly CO-reactive mitochondria was reduced in the CIH group, indicating reduced mitochondrial activity. Consistently, mitochondrial ETC enzyme activities and membrane potential were lowered in the CIH group. These findings suggest that hypoxia-induced respiratory plasticity was characterized by spatially confined mitochondrial alterations within postsynaptic spines in the pre-BötC neurons. In contrast to the robust plasticity evoked by dAIH preconditioning, a severe CIH challenge may weaken the local mitochondrial bioenergetics that the fuel postsynaptic activities of the respiratory motor drive.


Assuntos
Espinhas Dendríticas/metabolismo , Hipóxia/metabolismo , Bulbo/metabolismo , Mitocôndrias/ultraestrutura , Animais , Espinhas Dendríticas/ultraestrutura , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Hipóxia/patologia , Bulbo/ultraestrutura , Potencial da Membrana Mitocondrial , Mitocôndrias/metabolismo , Ratos , Ratos Sprague-Dawley , Sinapses/metabolismo , Sinapses/ultraestrutura
16.
Ann N Y Acad Sci ; 1478(1): 43-62, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32700392

RESUMO

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the hallmark pathologies of amyloid-beta plaques and neurofibrillary tangles. Symptoms of this devastating disease include behavioral changes and deterioration of higher cognitive functions. Impairment of neurogenesis has also been shown to occur in AD, which adversely impacts new neuronal cell growth, differentiation, and survival. This impairment possibly results from the cumulative effects of the various pathologies of AD. Preclinical studies have suggested that the administration of melatonin-the pineal hormone primarily responsible for the regulation of the circadian rhythm-targets the effects of AD pathologies and improves cognitive impairment. It is postulated that by mitigating the effect of these pathologies, melatonin can also rescue neurogenesis impairment. This review aims to explore the effect of AD pathologies on neurogenesis, as well as the mechanisms by which melatonin is able to ameliorate AD pathologies to potentially promote neurogenesis.


Assuntos
Doença de Alzheimer/terapia , Peptídeos beta-Amiloides/genética , Melatonina/genética , Neurogênese/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/genética , Disfunção Cognitiva/patologia , Disfunção Cognitiva/terapia , Modelos Animais de Doenças , Humanos , Melatonina/uso terapêutico , Neurônios/efeitos dos fármacos , Neurônios/patologia
17.
Behav Brain Res ; 385: 112559, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32097707

RESUMO

Measures of anxiety in behavioural tests remain largely unclear even decades after their establishment. Differences in the severity of anxiety measured by anxiety tests is an important issue that must be addressed. To test the hypothesis that the addition of light as an aversive stimulus will elicit a difference in behaviour between aged and young animals, we compared the responses of aged and young animals in the home cage emergence test (HCET) and elevated plus maze (EPM), in high aversive bright light and low aversive dim light conditions. In the HCET, our results demonstrated that young animals escaped with shorter latency and greater frequency than aged animals in both bright and dim light conditions, indicating that young animals display greater exploratory tendencies than aged animals. In the EPM, bright light conditions induced anxiogenic effects in both age groups. Interestingly, two-way ANOVA showed a significant interaction effect of age and light on the number of entries into the open arms of the EPM as well as frequency of escape in the HCET. These results show that the addition of light as an aversive stimulus in the EPM and HCET produced different responses in aged versus young animals in each test. In conclusion, significant interactions between age and light affected aged and young animals differently in the HCET and EPM, indicating that the two tests measure different aspects of anxiety.


Assuntos
Ansiedade , Comportamento Animal/fisiologia , Teste de Labirinto em Cruz Elevado , Comportamento Exploratório , Luz , Fatores Etários , Animais , Aprendizagem da Esquiva/fisiologia , Comportamento de Escolha/fisiologia , Ratos , Ratos Sprague-Dawley
18.
Aging Dis ; 11(1): 179-190, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32010491

RESUMO

Deep brain stimulation (DBS) is a promising treatment for many memory-related disorders including dementia, anxiety, and addiction. However, the use of DBS can be a paradoxical conundrum-dementia treatments aim to improve memory, whereas anxiety or addiction treatments aim to suppress maladaptive memory. In this review, the key hypotheses on how DBS affects memory are highlighted. We consolidate the findings and conclusions from the current research on the effects of DBS on memory in attempt to make sense of the bidirectional nature of DBS in disrupting and enhancing memory. Based on the current literature, we hypothesize that the timing of DBS plays a key role in its contradictory effects, and therefore, we propose a consolidated model of how DBS can both disrupt and enhance memory.

19.
Histol Histopathol ; 35(8): 833-847, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31975365

RESUMO

PURPOSE: This study aimed to investigate the role of cathepsin B dependent autophagy induced by chronic aerobic exercise on a high-fat diet (HFD)-induced nonalcoholic steatohepatitis (NASH) in rats. METHODS: Healthy female (Sprague-Dawley) SD rats (8-10 weeks old; 180g-200g; n=6 per group) were divided into: (1) control group; (2) HFD group; (3) Exercise group; (4) HFD + exercise group. Rats were fed with a normal chow or an HFD for 12 weeks. Rats with exercise ran on a rotarod for 30 min per day from weeks 9-12. RESULTS: Exercise training significantly (1) upregulated the levels of autophagy markers Beclin1, ATG5 and LC3II partly through inhibiting the p-AKT/mTOR pathway; (2) ameliorated HFD-mediated accumulation of fat mass by upregulating ß-oxidation regulator PPAR-α and downregulating fatty acid synthesis marker SREBP-1c via lipophagy; (3) diminished the HFD-induced hepatic pro-inflammatory mediators TNF-α and IL-1ß via NF-κB inactivation; (4) decreased the NASH-induced hepatic apoptotic marker caspase-3 activation caused by the upstream oxidative stress and by cytochrome P450 2E1 (CYP2E1); (5) mitigated the HFD-mediated lysosomal membrane permeabilisation and cathepsin B release partly via the reduction of reactive oxygen species (ROS). CONCLUSIONS: Chronic aerobic exercise reduces oxidative stress/ROS and ROS may cause lysosomal membrane destabilisation and disrupts the autophagic process. The beneficial effect of chronic exercise may further inhibit the process of lysosome membrane permeabilisation and facilitate lysosome fusion with autophagosomes to trigger autophagy. This process may possibly contribute to the inhibition of cathepsin B released into cytosol which further reduces inflammation and mitochondrial-dependent apoptosis.


Assuntos
Autofagia/fisiologia , Catepsina B/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Condicionamento Físico Animal/fisiologia , Animais , Dieta Hiperlipídica/efeitos adversos , Feminino , Hepatopatia Gordurosa não Alcoólica/etiologia , Ratos , Ratos Sprague-Dawley
20.
Neurosci Biobehav Rev ; 111: 57-68, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31846654

RESUMO

Neuromodulation techniques have shown promising efficacy on memory function and understanding the epigenetic mechanisms contributing to these processes would shed light on the molecular outcomes essential for cognition. In this review, we highlight some epigenetic mechanisms underlying neuromodulation and regulatory effects of neuronal activity-induced DNA methylation on genes that are highly involved in memory formation. Next, we examine the evidence to support DNA methyltransferase 3a, methyl-CpG binding protein 2, and DNA demethylase as possible memory modulation targets. Finally, we report the recent developments in the field of neuromodulation and explore the potential of these techniques for future neuroepigenetic research.


Assuntos
Metilação de DNA/fisiologia , Terapia por Estimulação Elétrica , Epigênese Genética/fisiologia , Hipocampo/fisiologia , Memória/fisiologia , Animais , DNA Metiltransferase 3A , Hipocampo/metabolismo , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...