Electromagnetic fields and spatial memory in adult rats: behavior and biomolecular approaches

Abstract The calcium/calmodulin protein kinase II (CaMKII) signaling cascade is crucial for hippocampus-dependent learning and memory. In adult rats, Hypothyroidism impairs hippocampus-dependent learning and memory, which can be prevented by simple replacement therapy with L-thyroxine (thyroxine, T4) treatment. In this study, we compared animal models of hypothyroidism induced by thyroidectomy and treatment with propylthiouracil (PTU). Our findings show that thyroidectomy and PTU models are equally effective as indicated by the identical plasma levels of thyroid stimulating hormone (TSH) and T4. The two model produced identical degree of inhibition of synaptic plasticity as indicated by depression of LTP. We then investigated the effect of thyroidectomy hypothyroidism and thyroxine treatment on the underlying molecular mechanism of spatial and non-spatial types of memory. To generate spatial memory, we used training in the radial arm water maze (RAWM) where rats had to locate a hidden platform. For non-spatial memory, rats were trained to swim to a clearly visible platform in an open swim field. Western blot analysis of hippocampal area CA1 revealed that training, on both mazes, of control and thyroxine-treated hypothyroid rats produced significant increases in the P-CaMKII, PKCγ, calcineurin and calmodulin protein levels, but the training failed to induce such increases in untreated thyroidectomized rats. As expected, we show that thyroxine therapy prevented the deleterious effects of hypothyroidism at the molecular level.

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The Effect of Prenatal Methamphetamine Exposure on Recognition Memory in Adult Rats

Prague Medical Report ◽

10.14712/23362936.2015.43 ◽

2015 ◽

Vol 116 (1) ◽

pp. 31-39 ◽

Cited By ~ 11

Author(s):

Markéta Fialová ◽

Jana Šírová ◽

Věra Bubeníková-Valešová ◽

Romana Šlamberová

Keyword(s):

Recognition Memory ◽

Spatial Memory ◽

Wistar Rats ◽

World Wide ◽

Novel Object Recognition ◽

Acute Administration ◽

Object Recognition Test ◽

Adult Rats ◽

Novel Object ◽

Female Wistar Rats

The use of methamphetamine (MA) among pregnant women is an increasing world-wide health problem. Prenatal MA exposure may cause changes in foetus but the exact effects have remained unclear. The aim of this study is to present the effect of prenatal MA exposure on recognition memory in adult rats. Adult female Wistar rats were injected daily with D-methamphetamine HCl (MA; 5 mg/kg, s.c.) during the entire gestation period. Control females were treated with saline in the same regime. Adult male offspring was administrated acutely by MA (1 mg/kg i.p.) or saline 30 minutes before beginning of an experiment. For testing recognition memory two tasks were chosen: Novel Object Recognition Test (NORT) and Object Location Test (OLT). Our results demonstrate that prenatally MA-exposed animals were worse in NORT independently on an acute administration of MA in adulthood. Prenatally MA-exposed rats did not deteriorate in OLT, but after acute administration of MA in adulthood, there was significant worsening compared to appropriate control. Prenatally saline-exposed offspring did not deteriorate in any test even after acute administration of MA. Our data suggest that prenatal MA exposure in rats cause impairment in recognition memory in adult offspring, but not in spatial memory. In addition, acute administration of MA to controls did not deteriorate either recognition or spatial memory.

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Comparing the Impact of Long-Term Exposure to Extremely Low-Frequency Electromagnetic Fields With Diverse Values on Anxiety, Memory, Learning, And Β-Amyloid Deposition In Adult Rats

Basic and Clinical Neuroscience Journal ◽

10.32598/bcn.2021.1204.2 ◽

2021 ◽

pp. 1-24

Author(s):

Nafiseh Faraji ◽

◽

Iraj Salehi ◽

Akram Alizadeh ◽

Arash Pourgholaminejad ◽

...

Keyword(s):

Electromagnetic Fields ◽

Low Frequency ◽

Amyloid Deposition ◽

Control Group ◽

Adult Rats ◽

Male Adult ◽

Extremely Low Frequency ◽

Β Amyloid ◽

The Impact ◽

The Brain

Background: Extremely low-frequency electromagnetic fields (ELF-EMFs) have gathered significant consideration for their possible pathogenicity. However, their effects on nervous system functions were not fully clarified. In this study, our aim was to assay the effect of ELF-EMFs with different intensity on memory, anxiety, antioxidant activity, beta amyloid (Aβ) deposition and microglia population in rats. Materials and Methods: Fifty male adult rats were randomly separated into 5 groups; four groups exposed to a flux density of 1, 100, 500 and 2000 microtesla (µT), 50 Hertz (Hz) frequency for 1h/day for 2 months and one group as a control group. The control group were without ELF-EMF stimulation. After 8 weeks, passive avoidance and elevated plus maze (EPM) tests was performed to assess memory formation and anxiety-like behavior, respectively. Total free thiol groups and the index of lipid peroxidation were assessed. Also, for detection of β-Amyloid deposition and stained microglia in the brain, anti-β-amyloid and anti-Iba1 antibodies were used. Results: In the ELF-EMF exposure groups, the step-through latency was significantly greater in the retention test (100,500, and 2000 µT) than in the control group (P<0.05). Also, the percentage of the entries into the open arms in ELF-EMF exposure groups (especially 2000 µT) decreased than control group (P <0.05). No β-Amyloid depositions were detected in the hippocampus of different groups. An increase in microglia numbers in the 100, 500 and 2000 µT groups was observed in compare to the control and 1 µT group. Conclusion: Exposure to ELF-EMF had an anxiogenic effect on rats and promoted memory and also induced oxidative stress. No β-Amyloid depositions were detected in the brain. Also, positive effect of ELF-EMF was observed on population of microglia population in the brain.

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