Disruption of neuronal-glial-vascular units in the hippocampus of ovariectomized mice injected with d-galactose

Involvement of Kir4.1 in pain insensitivity of the BTBR mouse model of autism spectrum disorder

Autism spectrum disorder (ASD) is a severe neurodevelopmental disorder. Abnormal pain sensation is a common clinical symptom of ASD that seriously affects the quality of life of patients with ASD and their families. However, the underlying mechanism is unclear. It is believed to be related to the excitability of neurons and the expression of ion channels. Herein, we confirmed that baseline pain and Complete Freund's adjuvant (CFA)-induced chronic inflammatory pain were impaired in the BTBR T+ Itpr3tf/J (BTBR) mouse model of ASD. RNA sequencing (RNA-seq) analyses of the dorsal root ganglia (DRG), which are closely related to pain in ASD model mice, revealed that high expression of KCNJ10 (encoding Kir4.1) might be an important factor in ASD pain sensation abnormalities. The levels of Kir4.1 were further verified by western blotting, RT-qPCR, and immunofluorescence. By inhibiting Kir4.1, the pain insensitivity of BTBR mice improved, confirming that a high expression level of Kir4.1 was highly correlated with decreased pain sensitivity in ASD. Meanwhile, we found that the anxiety behaviours and the social novelty recognition were changed after CFA induced inflammatory pain. And after inhibiting Kir4.1, the stereotyped behaviours and social novelty recognition of BTBR mice were also improved. Further, we found that the expression levels of glutamate transporters, excitatory amino acid transporter 1 (EAAT1), and excitatory amino acid transporter 2 (EAAT2) were increased in the DRG of BTBR mice but decreased after inhibiting Kir4.1. This suggests that Kir4.1 may play a key role in the improvement of pain insensitivity in ASD by regulating glutamate transporters. In conclusion, our findings revealed the possible mechanism and role of Kir4.1 in the pain insensitivity in ASD, using bioinformatics analyses and animal experiments, and provided a theoretical basis for clinically targeted intervention in ASD.

Disruption of α-Synuclein proteostasis in the striatum and midbrain of long-term ovariectomized female mice

Epidemiological studies have demonstrated that women are less susceptible to Parkinson's disease (PD) than men. Estrogen exposure is hypothesized to confer protection against dopaminergic neuronal loss in patients with PD. Although the accumulation and propagation of α-synuclein (α-Syn) are closely linked to the clinical progression of PD, no relevant research has examined whether α-Syn proteostasis in the brain is altered in women after menopause. In this study, we established long-term ovariectomized (OVX) mice to simulate late post-menopause and investigated the expression and aggregation of α-Syn following the ovariectomy procedure. We observed that the OVX mice exhibited a significant increase in the expression and aggregation of α-Syn in the striatum and midbrain accompanied by impaired motor performance at 3 months after ovariectomy. The accumulation of α-Syn did not result in a significant loss of nigral dopaminergic neurons but did enhance autophagy and neuroglial activation. These findings imply that menopause may disrupt α-Syn proteostasis and exacerbate the accumulation of α-Syn in the basal ganglia circuit.

Establishment of the concurrent experimental model of osteoporosis combined with Alzheimer's disease in rat and the dual-effects of echinacoside and acteoside from Cistanche tubulosa

ETHNOPHARMACOLOGICAL RELEVANCE

Cistanche tubulosa is a precious traditional Chinese medicine that has been widely used in the treatment of osteoporosis and Alzheimer's disease. Echinacoside and acteoside are the main active constituents in Cistanche tubulosa that have the pharmacological activities with research value. It has been reported that echinacoside and acteoside could improve the learning and memory ability, promote the proliferation and differentiation of osteoblast.

AIM OF STUDY

Echinacoside and acteoside from Cistanche tubulosa have shown significant activities of anti-osteoporosis and anti-Alzheimer's disease, while these effects have not been studied concurrently in a rat model. The aim of this study was to establish and verify the model of osteoporosis combined with Alzheimer's disease in rat, and to investigate the double effects of echinacoside and acteoside on this concurrent model.

MATERIALS AND METHODS

Three model groups of ovariectomy (OVX), sham surgery with D-galactose and AlCl₃ (D), ovariectomy with D-galactose and AlCl₃ (OVX + D) were set at the same time. The rats in drug treatment groups were ovariectomized. While conducting the intraperitoneal injection of D-galactose and intragastric administration of AlCl₃ in the rats of drug treatment groups, the rats were orally administered echinacoside (90 mg/kg/d), acteoside (90 mg/kg/d) and the positive control drugs of estradiol valerate (0.6 mg/kg/d), donepezil HCl (0.8 mg/kg/d), respectively. After the drug treatment of 8 weeks, Morris Water Maze (MWM) test for 6 days was firstly performed. The rats were then sacrificed to harvest the blood, uteri, femora, tibiae and brain tissues. The serum was used for biochemical tests. The uteri were used for histomorphometry. The right femora were used for Micro-CT and histomorphometry, respectively. The right tibiae were used for biomechanical test. The hippocampus collected on ice box was used for biochemical tests. The brain collected by perfusion was used for histomorphometry.

RESULTS

Compared with Sham group, OVX + D group could significantly reduce the learning and memory ability by causing oxidative damage, impairing neurons in hippocampus and affecting the hydrolysis and synthesis of acetylcholine. Meanwhile, the activities of BALP and TRAP in OVX + D group increased significantly (P < 0.001) as compared to Sham group. In addition, compared with Sham group, the mean bone mineral density obviously decreased (P < 0.05), the trabecular bone mass and microarchitecture were also destroyed significantly in OVX + D group. Furthermore, the maximum load and maximum stress significantly reduced (P < 0.01) and the energy absorption also decreased greatly as compared to Sham group. After administrated with echinacoside and acteoside, the typical pathological features of osteoporosis and Alzheimer's disease were ameliorated.

CONCLUSIONS

The model of osteoporosis combined with Alzheimer's disease in rat was feasible and successfully established. Echinacoside and acteoside also showed some significant effects on this concurrent model, and they could be potential candidates from Cistanche tubulosa with double effects for further study.

Effect of β-asarone in normal and β-amyloid-induced Alzheimeric rats

INTRODUCTION

β-Asarone is a major component of Acorus tatarinowii Schott. It has pharmacological effects that include antihyperlipidemic, anti-inflammatory, and antioxidant activity. In the present study, the effect of β-asarone on neurodegeneration induced by intrahippocampal administration of β-amyloid was investigated in adult male Wistar rats.

MATERIAL AND METHODS

The rats were randomly divided into 9 groups: normal control, sham-operated control, β-asarone (12.5, 25, and 50 mg/kg intragastrically, daily) alone, Alzheimeric control rats (β-amyloid, intrahippocampal), β-asarone (12.5, 25, and 50 mg/kg intragastrically, daily) together with β-amyloid, and treatment was performed accordingly. Animals were injected with β-amyloid bilaterally. Animals received β-asarone daily using an intragastric tube for 50 days, starting from 30 days before administration of the β-amyloid. The rats were sacrificed and parameters of oxidative stress, superoxide dismutase (SOD) and glutathione peroxidase (GPX) activity were measured in hippocampus homogenate. Histopathological changes were examined by Bielschowsky staining.

RESULTS

Our results showed that administration of β-asarone (25 and 50 mg/kg) significantly increased the levels of antioxidant enzymes, including SOD (1.09 ±0.02, 1.21 ±0.02, p < 0.001, respectively) and GPX (58.94 ±0.78, 68.92 ±3.64, p < 0.001, respectively) in comparison with Alzheimeric control rats (SOD and GPX level for Alzheimeric control group: 0.44 ±0.01, 35.09 ±1.15, respectively). Histopathological examination showed that β-asarone decreased cell loss in the cerebral cortex and hippocampus in Alzheimeric rats.

CONCLUSIONS

These results indicate that β-asarone is effective in providing protection against oxidative stress and neuronal damage induced by β-amyloid.

Astroglial connexins and cognition: memory formation or deterioration?

Connexins are the membrane proteins that form high-conductance plasma membrane channels and are the important constituents of gap junctions and hemichannels. Among different types of connexins, connexin 43 is the most widely expressed and studied gap junction proteins in astrocytes. Due to the key involvement of astrocytes in memory impairment and abundant expression of connexins in astrocytes, astroglial connexins have been projected as key therapeutic targets for Alzheimer's disease. On the other hand, the role of connexin gap junctions and hemichannels in memory formation and consolidation has also been reported. Moreover, deletion of these proteins and loss of gap junction communication result in loss of short-term spatial memory. Accordingly, both memory formation and memory deteriorating functions of astrocytes-located connexins have been documented. Physiologically expressed connexins may be involved in the memory formation, while pathologically increased expression of connexins with consequent excessive activation of astrocytes may induce neuronal injury and cognitive decline. The present review describes the memory formation as well as memory deteriorating functions of astroglial connexins in memory disorders of different etiology with possible mechanisms.

Beneficial and Detrimental Remodeling of Glial Connexin and Pannexin Functions in Rodent Models of Nervous System Diseases

A variety of glial cell functions are supported by connexin and pannexin proteins. These functions include the modulation of synaptic gain, the control of excitability through regulation of the ion and neurotransmitter composition of the extracellular milieu and the promotion of neuronal survival. Connexins and pannexins support these functions through diverse molecular mechanisms, including channel and non-channel functions. The former comprise the formation of gap junction-mediated networks supported by connexin intercellular channels and the formation of pore-like membrane structures or hemichannels formed by both connexins and pannexins. Non-channel functions involve adhesion properties and the participation in signaling intracellular cascades. Pathological conditions of the nervous system such as ischemia, neurodegeneration, pathogen infection, trauma and tumors are characterized by distinctive remodeling of connexin expression and function. However, whether these changes can be interpreted as part of the pathogenesis, or as beneficial compensatory effects, remains under debate. Here we review the available evidence addressing this matter with a special emphasis in mouse models with selective manipulation of glial connexin and pannexin proteins in vivo. We postulate that the beneficial vs. detrimental effects of glial connexin remodeling in pathological conditions depend on the impact of remodeling on the different connexin and pannexin channel and non-channel functions, on the characteristics of the inflammatory environment and on the type of interaction among glial cells types.

Hypoxic Preconditioning Maintains GLT-1 Against Transient Global Cerebral Ischemia Through Upregulating Cx43 and Inhibiting c-Src

Transient global cerebral ischemia (tGCI) causes excessive release of glutamate from neurons. Astrocytic glutamate transporter-1 (GLT-1) and glutamine synthetase (GS) together play a predominant role in maintaining glutamate at normal extracellular concentrations. Though our previous studies reported the alleviation of tGCI-induced neuronal death by hypoxic preconditioning (HPC) in hippocampal Cornu Ammonis 1 (CA1) of adult rats, the underlying mechanism has not yet been fully elaborated. In this study, we aimed to investigate the roles of GLT-1 and GS in the neuroprotection mediated by HPC against tGCI and to ascertain whether these roles can be regulated by connexin 43 (Cx43) and cellular-Src (c-Src) activity. We found that HPC decreased the level of extracellular glutamate in CA1 after tGCI via maintenance of GLT-1 expression and GS activity. Inhibition of GLT-1 expression with dihydrokainate (DHK) or inhibition of GS activity with methionine sulfoximine (MSO) abolished the neuroprotection induced by HPC. Also, HPC markedly upregulated Cx43 and inhibited p-c-Src expression in CA1 after tGCI, whereas inhibition of Cx43 with Gap26 dramatically reversed this effect. Furthermore, inhibition of p-c-Src with 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo (3, 4-d) pyrimidine (PP2) decreased c-Src activity, increased protein levels of GLT-1 and Cx43, enhanced GS activity, and thus reduced extracellular glutamate level in CA1 after tGCI. Collectively, our data demonstrated that reduced extracellular glutamate induced by HPC against tGCI through preventing the reduction of GLT-1 expression and maintaining GS activity in hippocampal CA1, which was mediated by upregulating Cx43 expression and inhibiting c-Src activity.

The role of aquaporin-4 in synaptic plasticity, memory and disease

Since the discovery of aquaporins, it has become clear that the various mammalian aquaporins play critical physiological roles in water and ion balance in multiple tissues. Aquaporin-4 (AQP4), the principal aquaporin expressed in the central nervous system (CNS, brain and spinal cord), has been shown to mediate CNS water homeostasis. In this review, we summarize new and exciting studies indicating that AQP4 also plays critical and unanticipated roles in synaptic plasticity and memory formation. Next, we consider the role of AQP4 in Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), multiple sclerosis (MS), neuromyelitis optica (NMO), epilepsy, traumatic brain injury (TBI), and stroke. Each of these conditions involves changes in AQP4 expression and/or distribution that may be functionally relevant to disease physiology. Insofar as AQP4 is exclusively expressed on astrocytes, these data provide new evidence of "astrocytopathy" in the etiology of diverse neurological diseases.

Chronic cerebral hypoperfusion induces memory deficits and facilitates Aβ generation in C57BL/6J mice

Alzheimer's disease (AD) is the most common type of dementia frequently responsible for cognitive decline in the elderly. The etiology and molecular mechanism of AD pathogenesis remain inconclusive. Aging and vascular factors are important independent causes and contributors to sporadic AD. Clinical imaging studies showed that cerebral blood flow decreases before cognitive impairment in patients with AD. To investigate the effect of chronic cerebral hypoperfusion (CCH) on cognitive impairment and morphological features, we developed a new manner of CCH mouse model by narrowing bilateral common carotid arteries. Mice started to manifest spatial memory deficits 1month after the surgery and exhibited behavioral changes in a time-dependent manner. Mice also presented memory deficits accompanied with morphological changes at the neuronal and synaptic levels. CCH damaged the normal neuronal morphology and significantly reduced the expression level of PSD95. CCH activated astrocytes, increased the co-expression of GFAP and AQP4, and destroyed the blood-brain barrier (BBB). Furthermore, CCH facilitated intracellular and extracellular Aβ deposition by up-regulating γ-secretase and β-secretase levels. Our results showed good reproducibility of post-CCH pathological processes, which are characterized by neuronal apoptosis, axonal abnormalities, glial activation, BBB damage, amyloid deposition, and cognitive dysfunction; these processes may be used to decipher the complex interplay and pathological process between CCH and AD. This study provides laboratory evidence for the prevention and treatment of cognitive malfunction and AD.

Changes in astrocyte functional markers and β-amyloid metabolism-related proteins in the early stages of hypercholesterolemia

Cholesterol is an essential substance for maintaining normal structure and function of the brain. But unfortunately, a long-term high-cholesterol diet can lead to a variety of pathological changes of the brain such as β-amyloid (Aβ) accumulation, Tau hyperphosphorylation, reactive gliosis, neuroinflammation, neuronal death and synaptic degeneration. These pathological changes have complex internal relations with one other, causing memory impairment and participating in the pathogenesis of Alzheimer's disease (AD). However, early hypercholesterolemia-induced events that lead to brain deterioration are not clear. To address this, 6-month-old female mice were fed a 3% cholesterol diet for 8weeks, followed by behavioral, biochemical and neuropathological analyses. The high-cholesterol-fed mice did not show neuronal and synaptic impairment or cognitive deficits compared with mice given a normal diet, but astrocytes were mildly activated with increased expression of functional markers including apolipoprotein E and aquaporin 4 in the hippocampus. Hippocampal interleukin-1β expression slightly increased, but interleukin-6 (IL-6) and tumor necrosis factor-α did not change significantly compared with those in the control group. Levels of Aβ, and its precursor protein, were unaffected, but levels of presenilin 1 and insulin-degrading enzyme (IDE), that initiate Aβ generation and degradation, respectively, increased in the hippocampus of the model mice. In addition, Tau phosphorylation levels were not different between the control and model groups. These results suggest that changes in astrocyte functional markers and Aβ metabolism proteins, which contribute to maintaining brain cholesterol and Aβ homeostasis, are early events in the process of hypercholesterolemia-related neuropathological changes.

Neuroprotective activity of hydroponic Teucrium polium following bilateral ovariectomy

Ovariectomy is known as "surgical menopause" with decreased levels of estrogen in female rodents. Its reported risks and adverse effects include cognitive impairment. The action of hydroponic Teucrium polium on nucleus basalis of Meynert (bnM) neurons following 6 weeks of ovariectomy was carried out. The analysis of spike activity was observed by on-line selection and the use of a software package. Early and late tetanic, - posttetanic potentiation and depression of neurons to high frequency stimulation of hippocampus were studied. The complex averaged peri-event time and frequency histograms were constructed. The histochemical study of the activity of Са(2+)-dependent acid phosphatase was observed. In conditions of hydroponic Teucrium polium administration, positive changes in neurons and gain of metabolism leading to cellular survival were revealed. The administration of Teucrium polium elicited neurodegenerative changes in bnM.

Astrocytes in neuroprotection and neurodegeneration: The role of connexin43 and pannexin1

The World Health Organization has predicted that by 2040 neurodegenerative diseases will overtake cancer to become the world's second leading cause of death after cardiovascular disease. This has sparked the development of several European and American brain research initiatives focusing on elucidating the underlying cellular and molecular mechanisms of neurodegenerative diseases. Connexin (Cx) and pannexin (Panx) membrane channel proteins are conduits through which neuronal, glial, and vascular tissues interact. In the brain, this interaction is highly critical for homeostasis and brain repair after injury. Understanding the molecular mechanisms by which these membrane channels function, in health and disease, might be particularly influential in establishing conceptual frameworks to develop new therapeutics against Cx and Panx channels. This review focuses on current insights and emerging concepts, particularly the impact of connexin43 and pannexin1, under neuroprotective and neurodegenerative conditions within the context of astrocytes.

Vascular degeneration in Parkinson's disease

Vascular degeneration plays a significant role in contributing to neurodegenerative conditions such as Alzheimer's disease. Our understanding of the vascular components in Parkinson's disease (PD) is however limited. We have examined the vascular morphology of human brain tissue from both PD and the control cases using immunohistochemical staining and image analysis. The degenerative morphology seen in PD cases included the formation of endothelial cell "clusters," which may be contributed by the fragmentation of capillaries. When compared to the control cases, the capillaries of PDs were less in number (P < 0.001), shorter in length (P < 0.001) and larger in diameter (P < 0.01) with obvious damage to the capillary network evidenced by less branching (P < 0.001). The level of degeneration seen in the caudate nucleus was also seen in the age-matched control cases. Vessel degeneration associated with PD was, however, found in multiple brain regions, but particularly in the substantia nigra, middle frontal cortex and brain stem nuclei. The data suggest that vascular degeneration could be an additional contributing factor to the progression of PD. Thus, treatments that prevent vascular degeneration and improve vascular remodeling may be a novel target for the treatment of PD.

Piperine and curcumin exhibit synergism in attenuating D-galactose induced senescence in rats

Aging is associated with progressive decline in mental abilities and functional capacities. Postmitotic tissues are most vulnerable to alteration due to oxidative damage leading to behavioral and biochemical changes. We hypothesized that the anatomical and functional facets of the brain could be protected with powerful antioxidants such as piperine and curcumin by examining their effects individually and in combination in delaying senescence induced by d-galactose. Young adult male Wistar rats were treated with piperine (12 mg/kg) alone, and curcumin (40 mg/kg) alone; and in combination for a period of 49 days by the oral route with treatment being initiated a week prior to d-galactose (60 mg/kg, i.p.). A control group, d-galactose alone and naturally aged control were also evaluated. Behavioral tests, hippocampal volume, CA1 neuron number, oxidative parameters, formation of lipofuscin like autofluorescent substances, neurochemical estimation, and histopathological changes in CA1 region of hippocampus were established. Our results suggest that the combination exerted a superior response compared to monotherapy as evidenced by improved spatial memory, reduced oxidative burden, reduced accumulation of lipofuscin; improvement in signaling, increase in hippocampal volume and protection of hippocampal neurons. We speculate that the powerful antioxidant nature of both, augmented response of curcumin in the presence of piperine and enhanced serotoninergic signaling was responsible for improved cognition and prevention in senescence.

Cerebrovascular protection of β-asarone in Alzheimer's disease rats: a behavioral, cerebral blood flow, biochemical and genic study

AIM OF THE STUDY

Recent studies have suggested that β-asarone have neuroprotective and cardiovascular protective effects in animal model. However, the influence of β-asarone on cerebrovascular system has not been explored so far. Therefore, present study was designed to determine whether repeated exposures to β-asarone resulted in positive effects on cerebrovascular function in AD rats.

MATERIALS AND METHODS

Alzheimer's disease induced rats was established by injecting both D-galactose (D-gal) and aluminum chloride (AlCl(3)) into abdominal cavity for 42 days. After injection of AlCl(3) and D-gal or saline for 28 days, the rats were treated with volume-matched vehicle or β-asarone (25mg/kg, 50mg/kg or 100mg/kg, i.h.) or Nimodipine (40mg/kg, i.g) once daily for consecutive 14 days, respectively. Behavioral responses of animals were assessed in a Morris water maze. CBF was measured by laser Doppler flowmetry. At the end of this period all rats were sacrificed, lactic acid, pyruvic acid content, Na+K+ATPase activity were determined in brain tissue homogenate to estimate the brain biochemical changes and mRNA expression of ET-1, eNOS and APP was measured with real-time RT-PCR method.

RESULTS

The spatial navigation task latencies, the times through platform zone and the time for the first through platform zone in the target quadrant in probe task, rCBF of right parietal lobe, the contents of lactic acid, pyruvic acid, and the activity of Na-K-ATP of cortex, and ET-1 and eNOS mRNA expression in hippocampus of AG rats were different from those of BG, P<0.05; The level of APP mRNA expression in model control group rats was higher than that in BG, though there was not a statistically significant difference, P>0.05; Compared with AG, HG rats spatial navigation task latencies were shorter, in probe task the times through platform zone in the target quadrant were bigger, rCBF and blood cell concentration of right parietal lobe were higher, the contents of pyruvic acid was lower, the activity of Na-K-ATP was higher, and ET-1 mRNA expression in hippocampus was lower, P<0.05; The level of eNOS and APP mRNA expression in HG rats was lower than that in AG, though there was not a statistically significant difference, P>0.05;

CONCLUSION

The present results suggested that β-asarone may be useful in memory impairment due to its cerebrovascular protection in AD rats and may develop as a therapeutic drug for treatment of AD patients.

Bmi-1 absence causes premature brain degeneration

Bmi-1, a polycomb transcriptional repressor, is implicated in cell cycle regulation and cell senescence. Its absence results in generalized astrogliosis and epilepsy during the postnatal development, but the underlying mechanisms are poorly understood. Here, we demonstrate the occurrence of oxidative stress in the brain of four-week-old Bmi-1 null mice. The mice showed various hallmarks of neurodegeneration including synaptic loss, axonal demyelination, reactive gliosis and brain mitochondrial damage. Moreover, astroglial glutamate transporters and glutamine synthetase decreased in the Bmi-1 null hippocampus, which might contribute to the sporadic epileptic-like seizures in these mice. These results indicate that Bmi-1 is required for maintaining endogenous antioxidant defenses in the brain, and its absence subsequently causes premature brain degeneration.

Aquaporin-4 deficiency exacerbates brain oxidative damage and memory deficits induced by long-term ovarian hormone deprivation and D-galactose injection

Astrocyte dysfunction is implicated in pathogenesis of certain neurological disorders including Alzheimer's disease (AD). A growing body of evidence indicates that water channel aquaporin-4 (AQP4) is a potential molecular target for the regulation astrocyte function. Recently, we reported that AQP4 expression was increased in the hippocampus of an AD mouse model established by long-term ovarian hormone deprivation combined with D-galactose (D-gal) exposure. However, pathophysiological roles and mechanisms of AQP4 up-regulation remain unclear. To address this issue, age-matched female wild-type and AQP4 null mice underwent ovariectomy, followed by D-gal administration for 8 wk. AQP4 null mice showed more severe brain oxidative stress, spatial learning and memory deficits, and basal forebrain cholinergic impairment than the wild-type controls. Notably, AQP4 null hippocampus contained more prominent amyloid-β production and loss of synapse-related proteins. These results suggested that ovariectomy and D-gal injection induced oxidative damage results in compensatory increases of AQP4 expression, and deficiency of AQP4 exacerbates brain oxidative stress and memory deficits. Therefore, regulation of astrocyte function by AQP4 may attenuate oxidative damage, offering a promising therapeutic strategy for AD.

Aquaporin-4 promotes memory consolidation in Morris water maze

Aquaporin-4 (AQP4), the most abundant aquaporin in the brain, is polarized at the glial end-feet facing peri-synaptic areas. AQP4 has been hypothesized to modulate water and potassium fluxes associated with neuronal activity in pathophysiological states. However, the role of AQP4 in astroglial signaling under physiological conditions is unclear. Herein, AQP4 knockout mice and wild-type littermates were tested in the Morris water maze (MWM), which allows for investigating the role of AQP4 in long-term learning and memory. Compared with wild-type mice, AQP4 knockout mice appeared actually to find the platform more easy, but to forget more quickly, in the MWM, indicating that AQP4 knockout mice exhibited impaired memory consolidation in MWM. Moreover, the deficits of memory consolidations were associated with defects in theta-burst stimulation-induced long-term potentiation both in vivo and in vitro. Furthermore, AQP4 knockout mice were accompanied by a decrease in the incorporation of adult-generated granule cells into spatial memory networks. Taken together, our findings indicate that AQP4 plays a modulatory role in memory consolidation. Targeting glial AQP4 may be a new therapeutic strategy for neurodegenerative disorders and related memory impairment.