Preventive effect of Ninjin-yoei-to, a Kampo medicine, on amyloid ß1-42-induced neurodegeneration via intracellular Zn2+ toxicity in the dentate gyrus.

Ninjin-yoei-to (NYT), a Kampo medicine, has ameliorative effects on cognitive dysfunction via enhancing cholinergic neuron activity. To explore an efficacy of NYT administration for prevention and cure of Alzheimer's disease, here we examined the effect of NYT on amyloid ß1-42 (Aß1-42)-induced neurodegeneration in the dentate gyrus. A diet containing 3% NYT was administered to mice for 2 weeks and human Aß1-42 was intracerebroventricularly injected. Neurodegeneration in the dentate granule cell layer of the hippocampus, which was determined 2 weeks after the injection, was rescued by administration of the diet for 4 weeks. Aß staining (uptake) was not modified in the dentate granule cell layer by pre-administration of the diet for 2 weeks, while Aß1-42-induced increase in intracellular Zn2+ was reduced, suggesting that pre-administration of NYT prior to Aß injection is effective for reducing Aß1-42-induced Zn2+ toxicity in the dentate gyrus. As a matter of fact, Aß1-42-induced neurodegeneration in the dentate gyrus was rescued by pre-administration of NYT. Interestingly, the level of metallothioneins, intracellular Zn2+-binding proteins, which can capture Zn2+ from Zn-Aß1-42 complexes, was elevated in the dentate granule cell layer by pre-administration of NYT. The present study suggests that pre-administration of NYT prevents Aß1-42-mediated neurodegeneration in the dentate gyurs by induced synthesis of metallothioneins, which reduces intracellular Zn2+ toxicity induced by Aß1-42.

Vitamin D deficiency as a potential risk factor for accelerated aging, impaired hippocampal neurogenesis and cognitive decline: a role for Wnt/ß-catenin signaling.

Vitamin D is an essential fat-soluble vitamin that participates in several homeostatic functions in mammalian organisms. Lower levels of vitamin D are produced in the older population, vitamin D deficiency being an accelerating factor for the progression of the aging process. In this review, we focus on the effect that vitamin D exerts in the aged brain paying special attention to the neurogenic process. Neurogenesis occurs in the adult brain in neurogenic regions, such as the dentate gyrus of the hippocampus (DG). This region generates new neurons that participate in cognitive tasks. The neurogenic rate in the DG is reduced in the aged brain because of a reduction in the number of neural stem cells (NSC). Homeostatic mechanisms controlled by the Wnt signaling pathway protect this pool of NSC from being depleted. We discuss in here the crosstalk between Wnt signaling and vitamin D, and hypothesize that hypovitaminosis might cause failure in the control of the neurogenic homeostatic mechanisms in the old brain leading to cognitive impairment. Understanding the relationship between vitamin D, neurogenesis and cognitive performance in the aged brain may facilitate prevention of cognitive decline and it can open a door into new therapeutic fields by perspectives in the elderly.

Bacopa monnieri (L.) Wettst. Extract Improves Memory Performance via Promotion of Neurogenesis in the Hippocampal Dentate Gyrus of Adolescent Mice.

Bacopa monnieri L. Wettst. (BM) is a botanical component of Ayurvedic medicines and of dietary supplements used worldwide for cognitive health and function. We previously reported that administration of BM alcoholic extract (BME) prevents trimethyltin (TMT)-induced cognitive deficits and hippocampal cell damage and promotes TMT-induced hippocampal neurogenesis. In this study, we demonstrate that administration of BME improves spatial working memory in adolescent (5-week- old) healthy mice but not adult (8-week-old) mice. Moreover, improved spatial working memory was retained even at 4 weeks after terminating 1-week treatment of adolescent mice. One-week BME treatment of adolescent mice significantly enhanced hippocampal BrdU incorporation and expression of genes involved in neurogenesis determined by RNAseq analysis. Cell death, as detected by histochemistry, appeared not to be significant. A significant increase in neurogenesis was observed in the dentate gyrus region 4 weeks after terminating 1-week treatment of adolescent mice with BME. Bacopaside I, an active component of BME, promoted the proliferation of neural progenitor cells in vitro in a concentration-dependent manner via the facilitation of the Akt and ERK1/2 signaling. These results suggest that BME enhances spatial working memory in healthy adolescent mice by promoting hippocampal neurogenesis and that the effects of BME are due, in significant amounts, to bacopaside I.

Mice lacking neuronal calcium sensor-1 show social and cognitive deficits.

Neuronal calcium sensor-1 or Frequenin is a calcium sensor widely expressed in the nervous system, with roles in neurotransmission, neurite outgrowth, synaptic plasticity, learning, and motivated behaviours. Neuronal calcium sensor-1 has been implicated in neuropsychiatric disorders including autism spectrum disorder, schizophrenia, and bipolar disorder. However, the role of neuronal calcium sensor-1 in behavioural phenotypes and brain changes relevant to autism spectrum disorder have not been evaluated. We show that neuronal calcium sensor-1 deletion in the mouse leads to a mild deficit in social approach and impaired displaced object recognition without affecting social interactions, behavioural flexibility, spatial reference memory, anxiety-like behaviour, or sensorimotor gating. Morphologically, neuronal calcium sensor-1 deletion leads to increased dendritic arbour complexity in the frontal cortex. At the level of hippocampal synaptic plasticity, neuronal calcium sensor-1 deletion leads to a reduction in long-term potentiation in the dentate gyrus, but not area Cornu Ammonis 1. Metabotropic glutamate receptor-induced long-term depression was unaffected in both dentate and Cornu Ammonis 1. These studies identify roles for neuronal calcium sensor-1 in specific subregions of the brain including a phenotype relevant to neuropsychiatric disorders.

Postsynaptic GluR2 Involved in Amelioration of Aß-Induced Memory Dysfunction by KAIXIN-San Through Rescuing Hippocampal LTP in Mice.

Kaixin-San (KXS), a Chinese formula, was used to treat "amnesia," a senile dementia in the modern world. This formula was reported to improve behavioral performances in many animal models. This study was designed to explore how KXS has improved amyloid-ß (Aß)-induced memory dysfunction in mice. The mouse models were achieved through unilateral ventricle injection with Aß42. The effects of KXS on memory improvement were evaluated by the step-down test. The electrophysiological changes induced by KXS were measured by long-term potentiation (LTP) analysis in the hippocampus in vivo. The expression of glutamate receptor 2 (GluR2) was observed through immunohistochemical staining. Behavioral experiment outcome demonstrated reduced avoidance time and increased error time during the step-down test in the mice of Aß group. This memory impairment, however, was reversed by KXS. Electrophysiological experiment showed no significant difference between Aß group and KXS group either in the size or the shape of field excitatory postsynaptic potentiation recorded from perforant path to dentate gyrus pathway. However, LTP in this region was reduced by Aß and recovered by KXS administration. Moreover, immunohistochemical staining showed increased postsynaptic GluR2 expression in DG area in KXS group. These findings suggest that Aß results in impairment to memory function of the animals, and KXS protects the animal from memory loss by rescuing LTP through postsynaptic mechanism which refers to increasing GluR2 expression.

Recovery of hippocampal functions and modulation of muscarinic response by electroacupuncture in young diabetic rats.

The muscarinic receptor response to acetylcholine regulates the hippocampal-related learning, memory, neural plasticity and the production and processing of the pro-nerve growth factor (proNGF) by hippocampal cells. The development and progression of diabetes generate a mild cognitive impairment reducing the functions of the septo-hippocampal cholinergic circuitry, depressing neural plasticity and inducing proNGF accumulation in the brain. Here we demonstrate, in a rat model of early type-1 diabetes, that a physical therapy, the electroacupuncture, counteracts the diabetes-induced deleterious effects on hippocampal physiology by ameliorating hippocampal-related memory functions; recovering the impaired long-term potentiation at the dentate gyrus (DG-LTP) and the lowered expression of the vesicular glutamate transporter 1; normalizing the activity-dependent release of proNGF in diabetic rat hippocampus. Electroacupuncture exerted its therapeutic effects by regulating the expression and activity of M1- and M2-acetylcholine muscarinic receptors subtypes in the dentate gyrus of hippocampus. Our results suggest that a physical therapy based on repetitive sensory stimulation could promote hippocampal neural activity, neuronal metabolism and functions, and conceivably improve the diabetes-induced cognitive impairment. Our data can support the setup of therapeutic protocols based on a better integration between physical therapies and pharmacology for the cure of diabetes-associated neurodegeneration and possibly for Alzheimer's disease.

Acupuncture Attenuated Vascular Dementia-Induced Hippocampal Long-Term Potentiation Impairments via Activation of D1/D5 Receptors.

BACKGROUND AND PURPOSE: Emerging evidence suggests that acupuncture could improve cognitive impairment in vascular dementia by enhancing synaptic plasticity in the hippocampus. The purpose of this study is to investigate whether dopamine, a key mediator of synaptic plasticity, is involved in this cognitive improvement. METHODS: Vascular dementia model was established by bilateral common carotid arteries occlusion in male Wistar rats. Three days after the operation, animals received acupuncture treatment for 2 weeks, once daily. The D1/D5 receptors antagonist SCH23390 was administered intraperitoneally 15 minutes before each acupuncture treatment. Morris water maze was examined after acupuncture. Long-term potentiation was studied by an electrophysiological technique. Dopamine and metabolites levels were detected by microdialysis and high-performance liquid chromatography from brain tissue. The expression of D1R and D5R was analyzed by immunofluorescence. RESULTS: Acupuncture remarkably reversed cognitive deficits in 2-vessel occlusion model (2VO) rats, and the acupuncture points Zusanli (ST36) and Baihui (GV20) were confirmed to be the most effective combination. Electrophysiological recording data showed that 2VO-induced impairments of long-term potentiation were prevented by acupuncture. In addition, acupuncture promoted the release of dopamine and its major metabolites in the hippocampus of 2VO rats. The immunofluorescence experiment showed that the decrease of D1R and D5R in hippocampal dentate gyrus region of 2VO rats was reversed by acupuncture. Furthermore, we found that the effects of acupuncture against 2VO-induced impairments in cognition and synaptic plasticity were abolished by SCH23390. CONCLUSIONS: Improvement in cognition and hippocampal synaptic plasticity induced by acupuncture was achieved via activation of D1/D5 receptors in 2VO rats.

The Role of Gastrodin on Hippocampal Neurons after N-Methyl-D-Aspartate Excitotoxicity and Experimental Temporal Lobe Seizures.

Tian ma (Gastrodia elata, GE) is an ancient Chinese herbal medicine that has been suggested to be effective as an anticonvulsant and analgesic, and to have sedative effects against vertigo, general paralysis, epilepsy and tetanus. The primary active ingredient isolated from GE is termed gastrodin, which is the glucoside of 4-hydroxybenzyl alcohol (4-HBA). Gastrodin can abolish hypoxia-, glutamate- and N-methyl-D-aspartate (NMDA) receptor-induced toxicity in primary culture of rat cortical neurons, and reduces seizure severity in seizure-sensitive gerbils. We evaluated the effect of gastrodin on NMDA excitotoxicity in hippocampal slice cultures (HSCs) with propidium iodide (PI) fluorescence measurement. We also evaluated the effects of gastrodin for treating active in vivo temporal lobe seizures induced by lithium/pilocarpine. Seizure severity, time span to seizure onset, mortality rate and hippocampal histology for survivors were compared. The effect of gastrodin was evaluated for treating in vitro seizures induced by Mg²âº-free medium in hippocampal slices. Frequencies and amplitudes of epileptiform discharges were compared. The effect of gastrodin on synaptic transmission was evaluated on hippocampal CA1 Schaffer collaterals. Application of 25 µM gastrodin significantly suppressed NMDA excitotoxicity in CA3 but not in CA1 hippocampus and dentate gyrus. Intraventricular gastrodin accelerated seizure onset for 12 min after intraperitoneal pilocarpine injection (P = 0.051). Three of five rats (60%) in the gastrodin group, and three of four (75%) in the dimethyl sulfoxide (DMSO) group died within 3 days after status epilepticus (SE). Gastrodin also failed to inhibit epileptiform discharges in hippocampal slices induced by Mg²âº-free medium, believed to be NMDA receptor-mediated spontaneous activity. The frequencies of the spontaneous epileptiform discharges were similar under treatments with 25 µM gastrodin, 200 µM gastrodin and DMSO. For the evaluation of gastrodin on synaptic transmission, application of DMSO, 25 µM or 200 µM gastrodin had no significant effect on excitatory postsynaptic potential (EPSP) slopes. Gastrodin at 200 µM decreased paired-pulse facilitation (PPF) from 1.23 ± 0.04 to 1.12 ± 0.04 (P = 0.002). In conclusion, gastrodin failed to suppress in vivo and in vitro seizures in our study. Gastrodin showed no effect on hippocampal Schaffer collateral EPSP. These findings suggest that gastrodin does not interact with ionotropic glutamate receptors to inhibit NMDA receptor-facilitated seizures. However, gastrodin showed protective effects against NMDA toxicity on cultured hippocampal slices. Nevertheless, gastrodin is still a potential neuroprotective agent against NMDA excitotoxicity, with potential benefits for stroke and patients with epilepsy.

Bangle (Zingiber purpureum) Improves Spatial Learning, Reduces Deficits in Memory, and Promotes Neurogenesis in the Dentate Gyrus of Senescence-Accelerated Mouse P8.

Bangle (Zingiber purpureum) is a tropical ginger that is used as a spice in Southeast Asia. Phenylbutenoid dimers isolated from Bangle have exhibited neurotrophic effects in primary cultured rat cortical neurons and PC12 cells. Furthermore, chronic treatment with phenylbutenoid dimers enhances hippocampal neurogenesis in olfactory bulbectomized mice. In this study, we investigated the effects of Bangle extract on behavior and hippocampal neurogenesis in vivo. SAMP8 mice, which are an established model for accelerated aging, with age-related learning and memory impairments, were given a Bangle-containing diet for 1 month, and subsequent behavioral tests and immunohistochemistry for Ki67, a proliferating cell marker, were performed. We found that the Bangle-containing diet improved spatial learning and memory deficits in the Morris water maze and significantly increased the numbers of Ki67-positive cells in the dentate gyrus of the SAMP8 mice. In addition, the Bangle extract exhibited a neurotrophin-like activity as indicated by the induction of neurite sprouting in PC12 cells. Our results suggest that Bangle is beneficial for the prevention of age-related progression of cognitive impairment.

Electroacupuncture promotes neural stem cell proliferation and neurogenesis in the dentate gyrus of rats following stroke via upregulation of Notch1 expression.

Neural stem cells (NSCs) are important in rehabilitation following stroke. Electroacupuncture (EA) treatment has been observed to promote the recovery of neurological functions subsequent to stroke, however, the effects of EA on the proliferation and differentiation of NSCs and its potential mechanisms remain to be elucidated. In the present study, rats, in which a stroke was induced through middle cerebral artery occlusion (MCAO), were treated with EA or control manipulation for 21 days. The modified Neurological Severity score and Morris water maze tests were used to assess the neurological functions of the rats. Bromodeoxyuridine (BrdU)/glial fibrillary acidic protein (GFAP) or BrdU/neuronal marker (NeuN) double immunofluorescence staining were used to examine the proliferation and differentiation of the NSCs. Reverse transcription quantitative polymerase chain reaction (RT­qPCR) and western blot analyses were performed to detect the expression levels of Notch1 and Hes1 in the dentate gyrus (DG) of the hippocampus of rats following MCAO. The results demonstrated that EA treatment significantly improved the neurological functional recovery of rats following stroke. A significant increase was observed in the number of BrdU+/GAFP+ and BrdU+/NeuN+ cells in the DG area in the EA­treated rats compared with that of the control group. RT­qPCR analysis revealed that EA treatment significantly increased the expression levels of Notch1 and Hes1, which may account for the enhanced proliferation and differentiation of NSCs. In conclusion, to the best of our knowledge, the present study was the first to demonstrate that EA treatment promoted NSC proliferation and neurogenesis in the DG area through the upregulation of Notch signaling following a stroke; therefore, EA may be a useful novel therapeutic strategy in future stroke treatment.

D-Galactose High-Dose Administration Failed to Induce Accelerated Aging Changes in Neurogenesis, Anxiety, and Spatial Memory on Young Male Wistar Rats.

The model of accelerated senescence with the prolonged administration of d-galactose is used in anti-aging studies because it mimics several aging-associated alterations such as increase of oxidative stress and decline of cognition. However, there is no standardized protocol for this aging model, and recently some reports have questioned its effectiveness. To clarify this issue, we used a model of high-dose d-galactose on 1-month-old male Wistar rats and studied the hippocampus, one of the most affected brain regions. In one group (n = 10), d-galactose was daily administered intraperitoneally (300 mg/kg) during 8 weeks whereas age-matched controls (n = 10) were injected intraperitoneally with saline. A third group (n = 10) was treated with the same dose of d-galactose and with oral epigallocatechin-3-gallate (EGCG) (2 grams/L), a green tea catechin with anti-oxidant and neuroprotective properties. After treatments, animals were submitted to open-field, elevated plus-maze and Morris water maze tests, and neurogenesis in the dentate gyrus subgranular layer was quantified. There were no significant alterations when the three groups were compared in the number of doublecortin- and Ki-67-immunoreactive cells, and also on anxiety levels, spatial learning, and memory. Therefore, d-galactose was not effective in the induction of accelerated aging, and EGCG administered to d-galactose-treated animals did not improve behavior and had no effects on neurogenesis. We conclude that daily 300 mg/kg of d-galactose administered intraperitoneally may not be a suitable model for inducing age-related neurobehavioral alterations in young male Wistar rats. More studies are necessary to obtain a reliable and reproducible model of accelerated senescence in rodents using d-galactose.

Berberine prevents nigrostriatal dopaminergic neuronal loss and suppresses hippocampal apoptosis in mice with Parkinson's disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the selective loss of nigral dopaminergic neurons and a reduction in striatal dopaminergic fibers, which result in tremors, rigidity, bradykinesia and gait disturbance. In addition to motor dysfunction, dementia is a widely recognized symptom of patients with PD. Berberine, an isoquinoline alkaloid isolated from Berberis vulgaris L., is known to exert anxiolytic, analgesic, anti-inflammatory, antipsychotic, antidepressant and anti-amnesic effects. In the present study, we investigated the effects of berberine on short-term memory in relation to dopamine depletion and hippocampal neurogenesis using a mouse model of PD, induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/P) treatment. Mice in the berberine-treated groups were orally administered berberine once a day for a total of 5 weeks. Our results revealed that the injection of MPTP/P induced dopaminergic neuronal death in the substantia nigra and fiber loss in the striatum. This resulted in impaired motor balance and coordination, as assessed by the beam walking test. We further demonstrated that MPTP/P-induced apoptosis in the hippocampus deteriorated short-term memory, as shown by the step-down avoidance task. By contrast, neurogenesis in the hippocampal dentate gyrus, which is a compensatory adaptive response to excessive apoptosis, was increased upon PD induction. However, treatment with berberine enhanced motor balance and coordination by preventing dopaminergic neuronal damage. Treatment with berberine also improved short-term memory by inhibiting apoptosis in the hippocampus. Berberine demonstrated maximal potency at 50 mg/kg. Based on these data, treatment with berberine may serve as a potential therapeutic strategy for the alleviation of memory impairment and motor dysfunction in patients with PD.

A Transient Upregulation of Glutamine Synthetase in the Dentate Gyrus Is Involved in Epileptogenesis Induced by Amygdala Kindling in the Rat.

Reduction of glutamine synthetase (GS) function is closely related to established epilepsy, but little is known regarding its role in epileptogenesis. The present study aimed to elucidate the functional changes of GS in the brain and its involvement in epileptogenesis using the amygdala kindling model of epilepsy induced by daily electrical stimulation of basolateral amygdala in rats. Both expression and activity of GS in the ipsilateral dentate gyrus (DG) were upregulated when kindled seizures progressed to stage 4. A single dose of L-methionine sulfoximine (MSO, in 2 µl), a selective GS inhibitor, was administered into the ipsilateral DG on the third day following the first stage 3 seizure (just before GS was upregulated). It was found that low doses of MSO (5 or 10 µg) significantly and dose-dependently reduced the severity of and susceptibility to evoked seizures, whereas MSO at a high dose (20 µg) aggravated kindled seizures. In animals that seizure acquisition had been successfully suppressed with 10 µg MSO, GS upregulation reoccurred when seizures re-progressed to stage 4 and re-administration of 10 µg MSO consistently reduced the seizures. GLN at a dose of 1.5 µg abolished the alleviative effect of 10 µg MSO and deleterious effect of 20 µg MSO on kindled seizures. Moreover, appropriate artificial microRNA interference (1 and 1.5×10(6) TU/2 µl) of GS expression in the ipsilateral DG also inhibited seizure progression. In addition, a transient increase of GS expression and activity in the cortex was also observed during epileptogenesis evoked by pentylenetetrazole kindling. These results strongly suggest that a transient and region-specific upregulation of GS function occurs when epilepsy develops into a certain stage and eventually promotes the process of epileptogenesis. Inhibition of GS to an adequate degree and at an appropriate timing may be a potential therapeutic approach to interrupting epileptogenesis.

Therapeutic potentials of an artificial oxygen-carrier, liposome-encapsulated hemoglobin, for ischemia/reperfusion-induced cerebral dysfunction in rats.

We performed this study to elucidate whether a newly developed liposome-encapsulated hemoglobin, TRM-645 (TRM), can prevent cerebral dysfunction resulting from acute ischemic stroke when used as an oxygen carrier. Hippocampal long-term potentiation (LTP) in the perforant path-dentate gyrus synapses and anxiety-related behaviors in the elevated plus-maze test were evaluated as indices of cerebral functional outcomes in the rat with two-vessel occlusion (2VO), which was induced by 10-min clamping of bilateral common carotid arteries. Saline or TRM (hemoglobin concentration of 6 g/dl: 2.5 or 5 ml/kg) was administered via the tail vein immediately after ischemic insult. Hippocampal LTP formation was markedly impaired and the open arm durations in the elevated plus-maze decreased significantly 4 days after 2VO, compared to those of sham-operated (control) rats, suggesting the hippocampal synaptic dysfunction and anxiogenic properties in 2VO rats. TRM (5 ml/kg) restored the hippocampal LTP formation and normalized the anxiety-related behavior. TRM also improved the decreased tissue oxygen partial pressure in the 2VO rat hippocampus, possibly due to oxygen delivery to ischemic regions. Liposome-encapsulated hemoglobin TRM might have therapeutic potentials for protecting the brain from neurological complications associated with acute ischemic stroke, as a promising blood substitute for oxygen therapy.

[Effect and mechanism of Coeloglossum viride var. bracteatum extract on scopolamine-induced deficits of learning and memory behavior of rodents].

The aim of the present study is to investigate the effect and mechanism of Coeloglossum viride var. bracteatum extract (CE) on scopolamine-induced learning and memory deficits. Learning and memory deficits of mice were evaluated by step-down passive avoidance test. Long-term potentiation of rats was detected in the dentate gyrus of hippocampus. Brain acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities were also determined. The results showed that scopolamine impaired learning and memory performance and LTP induction in hippocampus. Oral administration of CE (5, 10, and 20 mg x kg(-1)) significantly alleviated scopolamine-induced memory deficits measured by step-down test (P < 0.05). CE (5 mg x kg(-1), ip) significantly reversed the inhibitory effect of scopolamine on LTP in rats. In addition, CE was found to increase the activity of ChAT in rat brain. These results suggested that CE could alleviate scopolamine-induced learning and memory deficits, which might be due to the LTP-improvement and ChAT activity enhancement.

Neuroprotective effect of treatment with galantamine and choline alphoscerate on brain microanatomy in spontaneously hypertensive rats.

The present study was designed to assess if treatment with acetylcholinesterase inhibitor galantamine and the cholinergic precursor choline alphoscerate (alpha-glyceryl-phosphoryl-choline) alone or in association has any protective effect on brain microanatomy in spontaneously hypertensive rats (SHR) used as an animal model of vascular dementia (VaD). Thirty-two-week-old SHR and age-matched normotensive Wistar Kyoto (WKY) rats were left untreated or treated for 4 weeks with an oral dose of 3 mg/kg/day of galantamine, of 100 mg/kg/day of choline alphoscerate or their association. The number of neurons and of glial fibrillary acidic protein (GFAP) immunoreactive astrocytes, phosphorylated neurofilament, and microtubule associated protein-2 (MAP-2) and aquaporin-4 (AQP-4) was assessed by quantitative microanatomical and immunohistochemical techniques. In SHR, the number of neurons of frontal cortex, of the CA1 subfield of hippocampus and of dentate gyrus was decreased compared to WKY rats. Astrogliosis, breakdown of phosphorylated neurofilament, unchanged MAP-2 and altered AQP-4 expression were found as well. Both galantamine and choline alphoscerate countered nerve cell loss. Choline alphoscerate but not galantamine decreased astrogliosis and restored expression of AQ-4. Galantamine countered to a greater extent than choline alphoscerate phosphorylated neurofilament breakdown. The two drugs in association displayed a more remarkable effect. This study confirms a neuroprotective effect of galantamine in SHR and indicates a neuroprotective role of choline alphoscerate in the same model. A wider neuroprotective effect of the cholinergic inhibitor/precursor association was observed. These findings suggest to assess the activity of this cholinergic association in clinical trials.

Effect of electroacupuncture stimulation of hindlimb on seizure incidence and supragranular mossy fiber sprouting in a rat model of epilepsy.

Recently, electroacupuncture (EA) has been gaining more and more attention as a treatment for epilepsy. However, concrete evidence is needed to better understand its antiepileptic effect and the mechanism underlying this effect. The present study was designed to assess the effect of EA stimulation of hindlimb on the incidence of behavioral seizures (spontaneous recurrent seizures, [SRS]) and electroencephalogram (EEG) seizures, and the extent of supragranular mossy fiber sprouting (MFS) using the lithium-pilocarpine rat model of epilepsy. Sham EA at the same point without electrical stimulation was set as the control. EA and the sham EA were performed bilaterally (at the symmetrical Zusanli acupoints on both hind legs) 30 times every two days. The numbers of behavioral seizures and EEG seizures were then analyzed to evaluate the antiepileptic effect. After confirmation of the antiepileptic effect, MFS in the dentate gyrus (DG) supragranular layer was investigated by Timm's staining. The results showed that the EA stimulation of hindlimb significantly reduced the behavioral seizures, EEG seizures, and supragranular MFS; however, the sham EA without electrical stimulation showed no significant effect on seizures or supragranular MFS. The findings indicate that EA stimulation of hindlimb possesses an antiepileptic effect, which is probably related to its suppressive effect on aberrant MFS in DG.

The effect of electroacupuncture on spontaneous recurrent seizure and expression of GAD(67) mRNA in dentate gyrus in a rat model of epilepsy.

Concerns regarding the side effects of pharmacological approaches have recently increased interest in the use of acupuncture for treatment of epilepsy. Although clinical evidence for the acupunctural anti-epileptic effect has been demonstrated, the precise mechanism still remains unknown. The purpose of this study was to investigate the effect of electroacupuncture (EA) on spontaneous recurrent seizure (SRS) and expression of GAD(67) mRNA in dentate gyrus (DG) in epileptic rats. EA at bilateral acupoints of Zusanli (St36) was administered. Two sham EA controls were set: sham EA at bilateral nearby nonacupoints in the hamstring muscles, and sham EA at bilateral St36 without electrical stimulation. Lithium-pilocarpine injection was performed to establish the rat model of epilepsy at the 1st day. Three time points were set according to the day when the rats were killed (30th, 45th, 60th day). The results showed that EA at St36 significantly reduced the times of spontaneous recurrent seizure, neither of the two sham EA controls displayed significant effect on spontaneous recurrent seizure. Moreover, EA at St36 significantly elevated the expression of GAD(67) mRNA in DG granule cell layer (GCL), but not in the hilus; neither of the two sham controls showed significant effect on the expression of GAD(67) mRNA in granule cell layer or hilus. The findings suggest that EA at St36 possess some curative effect on epileptic rats, related with change of GAD(67) mRNA level in DG region.

Imaging the neural substrates involved in the genesis of pentylenetetrazol-induced seizures.

PURPOSE: Functional imaging of animal models makes it possible to map the functional neuroanatomy contributing to the genesis of seizures. Pentylenetetrazol (PTZ)-induced seizure in rats, a relevant model of human absence and of generalized tonic-clonic epilepsy, was used to stimulate seizure activity within 30 s of administration while collecting continuous, high-resolution, multislice images at subsecond intervals. METHODS: Pilot studies were conducted to establish a quick and effective PTZ model for the imaging experiments. PTZ was then used to stimulate seizure activity in rats while collecting multislice functional MRI (fMRI) images from the entire forebrain at 4.7 Tesla. Ethosuximide (ESM) also was used to block seizure activity. RESULTS: Within 2-4 s of PTZ administration, a rapid increase in blood oxygen level-dependent (BOLD) signal intensity was noted in the thalamus, especially the anterior thalamic nuclei. Activity in the anterior thalamus peaked approximately 15 s before seizure onset and was more than twofold greater than that in all other thalamic areas. The retrosplenial cortex showed a twofold greater increase in activity as compared with other cortical areas, also peaking at approximately 15 s. The dentate gyrus was twice as active as other hippocampal areas but peaked just before seizure onset. Treatment with ESM blocked seizures, decreasing PTZ-induced activation in most forebrain areas. The anterior thalamus and retrosplenial cortex were essentially blocked by pretreatment with ESM. CONCLUSIONS: The anterior thalamus, retrosplenial cortex, and dentate gyrus show the greatest increases in BOLD signal activity before seizure onset. Neurons in these areas may contribute to the neural network controlling the initiation of generalized tonic-clonic seizure.

Progenitor cell injury after irradiation to the developing brain can be modulated by mild hypothermia or hyperthermia.

Ionizing radiation induced acute cell death in the dentate gyrus subgranular zone (SGZ) and the subventricular zone (SVZ). Hypomyelination was also observed. The effects of mild hypothermia and hyperthermia for 4 h after irradiation (IR) were studied in postnatal day 9 rats. One hemisphere was irradiated with a single dose of 8 Gy and animals were randomized to normothermia (rectal temperature 36 degrees C for 4 h), hypothermia (32 degrees C for 4 h) or hyperthermia (39 degrees C for 4 h). Cellular injury, e.g. chromatin condensation and nitrotyrosine formation, appeared to proceed faster when the body temperature was higher. Caspase-3 activation was more pronounced in the hyperthermia group and nuclear translocation of p53 was less pronounced in the hypothermia group 6 h after IR. In the SVZ the loss of nestin-positive progenitors was more pronounced (48%) and the size was smaller (45%) in the hyperthermia group 7 days post-IR. Myelination was not different after hypo- or hyperthermia. This is the first report to demonstrate that hypothermia may be beneficial and that hyperthermia may aggravate the adverse side-effects after radiation therapy to the developing brain.