Methamphetamine and Modulation Functionality of the Prelimbic Cortex for Developing a Possible Treatment of Alzheimer’s Disease in an Animal Model

Alzheimer’s disease (AD) is a progressive neurodegenerative condition that causes cognitive impairment and other neuropsychiatric symptoms. Previously, little research has thus far investigated whether methamphetamine (MAMPH) can enhance cognitive function or ameliorate AD symptoms. This study examined whether a low dose of MAMPH can induce conditioned taste aversion (CTA) learning, or can increase plasma corticosterone levels, neural activity, and neural plasticity in the medial prefrontal cortex (mPFC) (responsible for cognitive function), the nucleus accumbens (NAc) and the amygdala (related to rewarding and aversive emotion), and the hippocampus (responsible for spatial learning). Furthermore, the excitations or lesions of the prelimbic cortex (PrL) can affect MAMPH-induced CTA learning, plasma corticosterone levels, and neural activity or plasticity in the mPFC [i.e., PrL, infralimbic cortex (IL), cingulate cortex 1 (Cg1)], the NAc, the amygdala [i.e., basolateral amygdala (BLA) and central amygdala (CeA)], and the hippocampus [i.e., CA1, CA2, CA3, and dentate gyrus (DG)]. In the experimental procedure, the rats were administered either saline or NMDA solutions, which were injected into the PrL to excite or destroy PrL neurons. Additionally, rats received 0.1% saccharin solution for 15 min, followed by intraperitoneal injections of either normal saline or 1 mg/kg MAMPH to induce CTA. A one-way ANOVA was performed to analyze the effects of saccharin intake on CTA, plasma corticosterone levels, and the expression of c-Fos and p-ERK. The results showed that the MAMPH induced CTA learning and increased plasma corticosterone levels. The mPFC, and particularly the PrL and IL and the DG of the hippocampus, appeared to show increased neural activity in c-Fos expression or neural plasticity in p-ERK expression. The excitation of the PrL neurons upregulated neural activity in c-Fos expression and neural plasticity in p-ERK expression in the PrL and IL. In summary, MAMPH may be able to improve cognitive and executive function in the brain and reduce AD symptoms. Moreover, the excitatory modulation of the PrL with MAMPH administration can facilitate MAMPH-induced neural activity and plasticity in the PrL and IL of the mPFC. The present data provide clinical implications for developing a possible treatment for AD in an animal model.

Download Full-text

Changes of Regional Neural Activity Homogeneity in Preclinical Alzheimer’s Disease: Compensation and Dysfunction

Frontiers in Neuroscience ◽

10.3389/fnins.2021.646414 ◽

2021 ◽

Vol 15 ◽

Author(s):

Zhen Zhang ◽

Liang Cui ◽

Yanlu Huang ◽

Yu Chen ◽

Yuehua Li ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Function ◽

Frontal Lobe ◽

Temporal Lobe ◽

Neural Activity ◽

Neuropsychological Tests ◽

Parietal Lobe ◽

Neuropsychological Test ◽

Potential Biomarker

IntroductionSubjective cognitive decline (SCD) is the preclinical stage of Alzheimer’s disease and may develop into amnestic mild cognitive impairment (aMCI). Finding suitable biomarkers is the key to accurately identifying SCD. Previous resting-state functional magnetic resonance imaging (rs-fMRI) studies on SCD patients showed functional connectivity disorders. Our goal was to explore whether local neurological homogeneity changes in SCD patients, the relationship between these changes and cognitive function, and similarities of neurological homogeneity changes between SCD and aMCI patients.Materials and Methods37 cases of the healthy control (HC) group, 39 cases of the SCD group, and 28 cases of the aMCI group were included. Participants underwent rs-fMRI examination and a set of neuropsychological test batteries. Regional homogeneity (ReHo) was calculated and compared between groups. ReHo values were extracted from meaningful regions in the SCD group, and the correlation between ReHo values with the performance of neuropsychological tests was analyzed.ResultsOur results showed significant changes in the ReHo among groups. In the SCD group compared with the HC group, part of the parietal lobe, frontal lobe, and occipital lobe showed decreased ReHo, and the temporal lobe, part of the parietal lobe and the frontal lobe showed increased ReHo. The increased area of ReHo was negatively correlated with the decreased area, and was related to decrease on multiple neuropsychological tests performance. Simultaneously, the changed areas of ReHo in SCD patients are similar to aMCI patients, while aMCI group’s neuropsychological test performance was significantly lower than that of the SCD group.ConclusionThere are significant changes in local neurological homogeneity in SCD patients, and related to the decline of cognitive function. The increase of neurological homogeneity in the temporal lobe and adjacent area is negatively correlated with cognitive function, reflecting compensation for local neural damage. These changes in local neurological homogeneity in SCD patients are similar to aMCI patients, suggesting similar neuropathy in these two stages. However, the aMCI group’s cognitive function was significantly worse than that of the SCD group, suggesting that this compensation is limited. In summary, regional neural activity homogeneity may be a potential biomarker for identifying SCD and measuring the disease severity.

Download Full-text

Effect of Endurance Exercise and MitoQ Intake on Tau Hyperphosphorylation, Oxidative Stress, Antioxidant Modulating Factors, Mitochondrial Function, and Cognitive Function in Alcl3-Induced Alzheimer’s Disease Animal Model

Exercise Science ◽

10.15857/ksep.2021.30.3.396 ◽

2021 ◽

Vol 30 (3) ◽

pp. 396-406

Author(s):

Jin-Hue Jeong ◽

Dong-Hun Choi ◽

Jeong-Kook Lee ◽

Joon-Yong Cho

Keyword(s):

Oxidative Stress ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Animal Model ◽

Cognitive Function ◽

Endurance Exercise ◽

Mitochondrial Function ◽

Treadmill Exercise ◽

Tau Hyperphosphorylation ◽

Positive Effect

PURPOSE: This study aimed to investigate the effect of 8 weeks of endurance exercise and MitoQ intake on tau hyperphosphorylation, oxidative stress, antioxidant modulating factors, mitochondrial function, and cognitive function in an AlCl3-induced Alzheimer’s disease animal model.METHODS: For the experimental animals, 40 mg/kg of aluminum chloride (AlCl3) was diluted with physiological saline for 60 days and intraperitoneally injected to create an Alzheimer’s disease animal model. In addition, endurance exercise was performed at a speed of 12 m/min using a treadmill for laboratory animals for 8 weeks, and MitoQ was applied with a 100 μm concentration of negative water. The rats were randomly divided into five groups: a saline control group (NC, n=6), an AlCl3 injection group (AC, n=6), an AlCl3 injection and treadmill exercise group (AE, n=6), an AlCl3 injection and MitoQ group (AM, n=6), and an AlCl3 injection and treadmill exercise and MitoQ intake group (AEM, n=6). The SPSS program was used for statistical analyses. Differences between the groups in each variable were analyzed using the one-way ANOVA.RESULTS: Endurance exercise and MitoQ intake for 8 weeks showed positive results in cognitive function and decreased tau hyperphosphorylation in the animal model with Alzheimer’s disease. In addition, they reduced oxidative stress (4-HNE, MDA) and had a positive effect on antioxidant indicators (catalase, SOD-1, SOD-2). Finally, they exhibited a positive effect on factors related to mitochondrial function (PGC-1, Tfam).CONCLUSIONS: Eight weeks of endurance exercise and MitoQ intake are thought to have a positive effect in alleviating Alzheimer’s disease in terms of improving cognitive function through AlCl3 accumulation, tau hyperphosphorylation, oxidative stress, antioxidant modulating factors, and mitochondrial function.

Download Full-text

Paired helical filaments (PHF) in rats: An experimental animal model for Alzheimer's disease

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128493 ◽

1987 ◽

Vol 45 ◽

pp. 842-843

Author(s):

V.J.A. Montpetit ◽

S. Dancea ◽

S.W. French ◽

D.F. Clapin

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Animal Model ◽

Paired Helical Filaments ◽

Ethanol Intoxication ◽

Drg Neurons ◽

Critical Difference ◽

Suitable Animal Model ◽

The Central Nervous System ◽

Chronic Ethanol Intoxication

A continuing problem in Alzheimer research is the lack of a suitable animal model for the disease. The absence of neurofibrillary tangles of paired helical filaments is the most critical difference in the processes by which the central nervous system ages in most species other than man. However, restricting consideration to single phenomena, one may identify animal models for specific aspects of Alzheimer's disease. Abnormal fibers resembling PHF have been observed in dorsal root ganglia (DRG) neurons of rats in a study of chronic ethanol intoxication and spontaneously in aged rats. We present in this report evidence that PHF-like filaments occur in ethanol-treated rats of young age. In control animals lesions similar in some respects to our observations of cytoskeletal pathology in pyridoxine induced neurotoxicity were observed.Male Wistar BR rats (Charles River Labs) weighing 350 to 400 g, were implanted with a single gastrostomy cannula and infused with a liquid diet containing 30% of total calories as fat plus ethanol or isocaloric dextrose.

Download Full-text