Neuronal-specific endoplasmic reticulum Mg2+/Ca2+ ATPase Ca2+ sequestration in mixed primary hippocampal culture homogenates

Neurological study on the effect of CeNPs and/or La Cl3 on adult male albino rats

Lanthanides are a group of 15 elements (8 heavy and 7 light) grouped for their proximity in the chemical and physical properties. Recently, this group of elements has received great attention because of their importance, and their entrance into many industrial technologies making the probability of the living organisms' exposure to it increase. The present study aims to study ability of cerium nanoparticles (CeNPs) or lanthanum (LaCl3) to cross the blood brain barrier also, investigate their neuro effect separately or together on some parameters in six brain areas (cortex, cerebellum, hippocampus, striatum, midbrain, and hypothalamus) of the adult male albino rats. The results showed the ability of both elements to distribute and accumulate in the different brain areas. Also, the results of CeNPs or LaCl3 treatment were in the same line where each element caused a significant decrease in norepinephrine (NE), dopamine (DA), serotonin (5-HT) and GABA accompanied with a significant increase in 5- hydroxyl indoleacetic acid (5-HIAA) glucose level. On the other hand, GSH and MDA showed a significant decrease after CeNPs treatment while, with LaCl3 treatment, MDA showed a significant increase in the different brain areas after 3 weeks of treatment. The coadministration of CeNPs and La Cl3 caused an ameliorating effect in all the tested parameters. In conclusion, from the previous studies the effects of lanthanides in the present study may be in part due to its effect on the release or turnover of neurotransmitters and insulin secretion. Finally, the ameliorative effect of CeNPs may be regarded as its high activity to scavenge the free radicals.

Neuronal-Specific Inhibition of Endoplasmic Reticulum Mg2+/Ca2+ ATPase Ca2+ Uptake in a Mixed Primary Hippocampal Culture Model of Status Epilepticus

Loss of intracellular calcium homeostasis is an established mechanism associated with neuronal dysfunction and status epilepticus. Sequestration of free cytosolic calcium into endoplasmic reticulum by Mg²⁺/Ca²⁺ adenosinetriphosphatase (ATPase) is critical for maintenance of intracellular calcium homeostasis. Exposing hippocampal cultures to low-magnesium media is a well-accepted in vitro model of status epilepticus. Using this model, it was shown that endoplasmic reticulum Ca²⁺ uptake was significantly inhibited in homogenates from cultures demonstrating electrophysiological seizure phenotypes. Calcium uptake was mainly neuronal. However, glial Ca²⁺ uptake was also significantly inhibited. Viability of neurons exposed to low magnesium was similar to neurons exposed to control solutions. Finally, it was demonstrated that Ca²⁺ uptake inhibition and intracellular free Ca²⁺ levels increased in parallel with increasing incubation in low magnesium. The results suggest that inhibition of Mg²⁺/Ca²⁺ ATPase-mediated endoplasmic reticulum Ca²⁺ sequestration contributes to loss of intracellular Ca²⁺ homeostasis associated with status epilepticus. This study describes for the first time inhibition of endoplasmic reticulum Mg²⁺/Ca²⁺ ATPase in a mixed primary hippocampal model of status epilepticus. In combination with animal models of status epilepticus, the cell culture model provides a powerful tool to further elucidate mechanisms that result in inhibition of Mg²⁺/Ca²⁺ ATPase and downstream consequences of decreased enzyme activity.

Centella asiatica Attenuates Diabetes Induced Hippocampal Changes in Experimental Diabetic Rats

Diabetes mellitus has been reported to affect functions of the hippocampus. We hypothesized that Centella asiatica, a herb traditionally being used to improve memory, prevents diabetes-related hippocampal dysfunction. Therefore, the aim of this study was to investigate the protective role of C. asiatica on the hippocampus in diabetes. Methods. Streptozotocin- (STZ-) induced adult male diabetic rats received 100 and 200 mg/kg/day body weight (b.w) C. asiatica leaf aqueous extract for four consecutive weeks. Following sacrifice, hippocampus was removed and hippocampal tissue homogenates were analyzed for Na(+)/K(+)-, Ca(2+)- and Mg(2+)-ATPases activity levels. Levels of the markers of inflammation (tumor necrosis factor, TNF-α; interleukin, IL-6; and interleukin, IL-1β) and oxidative stress (lipid peroxidation product: LPO, superoxide dismutase: SOD, catalase: CAT, and glutathione peroxidase: GPx) were determined. The hippocampal sections were visualized for histopathological changes. Results. Administration of C. asiatica leaf aqueous extract to diabetic rats maintained near normal ATPases activity levels and prevents the increase in the levels of inflammatory and oxidative stress markers in the hippocampus. Lesser signs of histopathological changes were observed in the hippocampus of C. asiatica leaf aqueous extract treated diabetic rats. Conclusions. C. asiatica leaf protects the hippocampus against diabetes-induced dysfunction which could help to preserve memory in this condition.

Neuroprotective effect of anthocyanins on acetylcholinesterase activity and attenuation of scopolamine-induced amnesia in rats

Anthocyanins are a group of natural phenolic compounds responsible for the color to plants and fruits. These compounds might have beneficial effects on memory and have antioxidant properties. In the present study we have investigated the therapeutic efficacy of anthocyanins in an animal model of cognitive deficits, associated to Alzheimer's disease, induced by scopolamine. We evaluated whether anthocyanins protect the effects caused by SCO on nitrite/nitrate (NOx) levels and Na(+),K(+)-ATPase and Ca(2+)-ATPase and acetylcholinesterase (AChE) activities in the cerebral cortex and hippocampus (of rats. We used 4 different groups of animals: control (CTRL), anthocyanins treated (ANT), scopolamine-challenged (SCO), and scopolamine+anthocyanins (SCO+ANT). After seven days of treatment with ANT (200mgkg(-1); oral), the animals were SCO injected (1mgkg(-1); IP) and were performed the behavior tests, and submitted to euthanasia. A memory deficit was found in SCO group, but ANT treatment prevented this impairment of memory (P<0.05). The ANT treatment per se had an anxiolytic effect. AChE activity was increased in both in cortex and hippocampus of SCO group, this effect was significantly attenuated by ANT (P<0.05). SCO decreased Na(+),K(+)-ATPase and Ca(2+)-ATPase activities in hippocampus, and ANT was able to significantly (P<0.05) prevent these effects. No significant alteration was found on NOx levels among the groups. In conclusion, the ANT is able to regulate cholinergic neurotransmission and restore the Na(+),K(+)-ATPase and Ca(2+)-ATPase activities, and also prevented memory deficits caused by scopolamine administration.

The toxicological effects in brain of mice following exposure to cerium chloride

Cerium (Ce) compounds are now widely applied in medicine, agriculture, animal breeding, and daily life; however, the effects of Ce on human body, especially on the central nervous system, are still unclear. In order to investigate whether Ce exposure cause neurotoxicological effects, ICR mice were exposed to CeCl(3) through intragastric administration at 0, 2, 10, and 20 mg/kg body weight doses everyday for 60 days. The behaviors of spatial recognition memory, brain histopathology, the brain elements and neurochemicals, as well as enzymes activities in mice were determined. The Y-maze test showed that CeCl(3) exposure could significantly impair the behaviors of spatial recognition memory. Specifically, in these Ln(3+)-treated mice, the contents of Ca, Mg, Na, K, Fe, and Zn in brain were significantly altered, the activities of Na(+)/K(+)-ATPase, Ca(2+)-ATPase, Ca(2+)/Mg(2+)-ATPase, acetylcholine esterase, and nitric oxide synthase were significantly inhibited; monoamines neurotransmitters such as norepinephrine, dopamine, and 5-hydroxytryptamine were significantly decreased, while the contents of acetylcholine, glutamate, and nitric oxide were significantly increased. These results indicated that CeCl(3) exposure could impair the learning ability, which is attributed to the disturbance of the homeostasis of trace elements, enzymes, and neurotransmitter systems in the mouse brain. Therefore, our study aroused the attention of Ln application and long-term exposure effects.

Long-term decrease in calbindin-D28K expression in the hippocampus of epileptic rats following pilocarpine-induced status epilepticus

Acquired epilepsy (AE) is characterized by spontaneous recurrent seizures and long-term changes that occur in surviving neurons following an injury such as status epilepticus (SE). Long-lasting alterations in hippocampal Ca(2+) homeostasis have been observed in both in vivo and in vitro models of AE. One major regulator of Ca(2+) homeostasis is the neuronal calcium binding protein, calbindin-D28k that serves to buffer and transport Ca(2+) ions. This study evaluated the expression of hippocampal calbindin levels in the rat pilocarpine model of AE. Calbindin protein expression was reduced over 50% in the hippocampus in epileptic animals. This decrease was observed in the pyramidal layer of CA1, stratum lucidum of CA3, hilus, and stratum granulosum and stratum moleculare of the dentate gyrus when corrected for cell loss. Furthermore, calbindin levels in individual neurons were also significantly reduced. In addition, the expression of calbindin mRNA was decreased in epileptic animals. Time course studies demonstrated that decreased calbindin expression was initially present 1 month following pilocarpine-induced SE and lasted for up to 2 years after the initial episode of SE. The results indicate that calbindin is essentially permanently decreased in the hippocampus in AE. This decrease in hippocampal calbindin may be a major contributing factor underlying some of the plasticity changes that occur in epileptogenesis and contribute to the alterations in Ca(2+) homeostasis associated with AE.

Ytterbium and trace element distribution in brain and organic tissues of offspring rats after prenatal and postnatal exposure to ytterbium

Lanthanides, because of their diversified physical and chemical effects, have been widely used in a number of fields. As a result, more and more lanthanides are entering the environment and eventually accumulating in the human body. Previous studies indicate that the impact of lanthanides on brain function cannot be neglected. Although neurological studies of trace elements are of paramount importance, up to now, little data are provided regarding the status of micronutritional elements in rats after prenatal and long-term exposure to lanthanide. The aim of this study is to determine the ytterbium (Yb) and trace elements distribution in brain and organic tissues of offspring rats after prenatal and long-term exposure to Yb. Wistar rats were exposed to Yb through oral administration at 0,0.1, 2, and 40 mg Yb/kg concentrations from gestation day 0 through 5 mo of age. Concentrations of Yb and other elements (Mg, Ca, Fe, Cu, Mn, and Zn) in the serum, liver, femur, and brain regions (cerebral cortex, hippocampus, cerebellum, and the rest) of offspring rats at the age of 0 d, 25 d, and 5 mo were analyzed by inductively coupled plasma-mass spectrometry. The accumulation of Yb in the brain, liver, and femur is observed; moreover, the levels of Fe, Cu, Mn, Zn, Ca, and Mg in the brain and organic tissues of offspring rats are also altered after Yb exposure. This disturbance of the homeostasis of trace elements might induce adverse effects on normal physiological functions of the brain and other organs.

Neurotoxicological consequence of long-term exposure to lanthanum

Lanthanides, because of their diversified physical and chemical effects, have been widely used in a number of fields. As a result, more and more lanthanides are entering into the environment and eventually accumulated in human body. Recently, a new medicine, lanthanum carbonate (Fosrenol), has been used to treat chronic renal failure (CRF), and the dosage is much higher than the daily intake of lanthanides. However, the effects of lanthanides on human body, especially on the central nervous system, are still unclear. The aim of this study was to determine whether long-term lanthanum exposure results in persistent alternations in nervous system function. Wistar rats were exposed to lanthanum chloride (LaCl(3)) through oral administration at 0, 0.1, 2 and 40mg/kg concentration from 4 weeks through 6 months of age. Morris water maze test showed that lanthanum exposure at 40mg/kg could significantly impair the behavioral performance. To fully investigate the neurotoxicological consequence of lanthanum exposure, brain elemental distributions and neurochemicals were also investigated. The distributions of brain elements such as Ca, Fe and Zn were significantly altered after lanthanum exposure. Moreover, 40mg/kg LaCl(3) significantly inhibited the activity of Ca(2+)-ATPase; the function of the central cholinergic system was also noticeably disturbed and the contents of some monoamines neurotransmitters were significantly decreased. These findings indicate that chronic exposure to lanthanum could possibly impair the learning ability and this deficit may be possibly attributed to the disturbance of the homeostasis of trace elements, enzymes and neurotransmitter systems in brain. Therefore, the application of lanthanide, especially in pharmacology, should be cautious.