Injection Of Artificial Cerebrospinal Fluid Research Articles

Role of alpha-7 nicotinic acetylcholine receptor down-regulation in cyclic nucleotide reduction in memory-related brain regions of Alzheimer’s rats

In this study, we investigated the effect of the downregulation of α7 nicotinic acetylcholine receptors (α7nAChRs) by Streptozotocin (STZ) on the level of cyclic nucleotides. Three groups of six rats each—Control, Sham (received an Intracerebroventricular injection of artificial cerebrospinal fluid, and STZ were formed. Except for the control group, all rats were anesthetized with 45 mg/kg of pentobarbitone. The STZ was administered intracerebroventricularly at a dose of 3 mg/kg to STZ group rats on Day 1 as well as Day 3 of an experimental period of 18 days. By using the Morris Water Maze (MWM) along with the Y-maze test, behavioral parameters were assessed, and biochemical analysis was assessed within the hippocampus, prefrontal cortex as well as amygdala of the rat brain. Statistical analysis was performed using repeated measures with one-way and two-way analysis of variance. Bonferroni and Student Newman–Keuls post hoc test was used to determine significance between experimental groups, with a significance threshold of p < 0.05. STZ administration resulted in a notable decline in the cognitive function of rats, as evidenced by longer transfer latency, reduced duration spent, and decreased overall distance covered within the designated quadrant (in percentage) in the MWM assessment. Moreover, STZ lowered the spontaneous change in behavior observed in the rodents during the Y-maze evaluation and decreased Cyclic Adenosine Monophosphate and Cyclic Guanosine Monophosphate (cyclic nucleotides) concentrations within the HIP, PFC, and Amygdale of rat brain regions. The α7nAChR downregulation may form a basis that could serve as a foundation for cognitive impairments alongside reduced cyclic nucleotides’ concentration in specific areas of the rat brain. Thus, cyclic nucleotides could be a probable target to stimulate the α7nAChR mediated mechanism in STZ-mediated conditions.

Highly specific gene therapy in a rat model of sporadic Alzheimer’s disease: use of adeno‐associated viral vectors to overexpress IGF1 in hippocampal astrocytes

AbstractBackgroundSporadic Alzheimer’s disease (sAD) is the most prevalent neurodegenerative disease. The cerebral histopathological study shows that the hippocampus (Hc) is severely affected and presents marked astroglial reactivity and in consequence, neuronal trophic support decreases. We set out to develop an astrocyte‐targeted therapy that prevents the detrimental actions of reactive astrocytes, enhance their neuroprotection, and restore their modulatory properties in our sAD rat model mediated by the intracerebroventricular (icv) injection of streptozotocin (STZ).Method AAV generation: Bicistronic serotype 9 adeno‐associated viruses (AAVs) driven by the gfaABC1D promoter (astrocyte specific) [Lee et al 2008. https://doi.org/10.1002/glia.20622] were generated by the 3‐plasmid system. Two vectors harbouring the cassettes gfaABC1D‐IGF1‐ires‐tdTomato (AAV‐IGF1) and gfaABC1D‐GFP‐ires‐tdTomato (AAV‐GFP) were constructed. AAVs characterization was performed by RT‐qPCR and immunohistochemistry (IHC). Gene therapy in Hc with AAV‐IGF1: Young male rats were used and divided into 3 groups: SHAM, GFP and IGF1. On Experimental Day (ED) ‐28, animals received bilateral injections of artificial cerebrospinal fluid (aCSF) (SHAM) or AAV‐GFP/IGF1(GFP/IGF1). At ED 0, animals received icv aCSF (SHAM) or STZ (GFP/IGF1) (3mg/kg) bilaterally. Among the ED +17/+26 behavioural tests were performed (Open Field Test, Novel Object Recognition Test, and Barnes Maze).ResultTransgenes overexpression was confirmed by RT‐qPCR and IHC. Vectors specificity was determined since 100% of the cells with red fluorescence (tdTomato+) were GFAP+. We also observed that a single injection of the vector is sufficient to transduce Hc throughout its rostro caudal extension. Animals belonging to the AAV‐GFP+STZ group showed a significant deterioration in the behavioural tests, while AAV‐IGF1+STZ animals did not show significant differences compared with the SHAM control in tested behaviours.ConclusionWe explored a targeted therapeutic approach with high specificity to hippocampal astrocytes, which allowed us to modulate astrocyte IGF1 expression, thus promoting neuroprotective effects and preventing behavioural decline in animals with sAD. Consequently, our results are encouraging and suggest that astrocyte manipulation can be approached as a promising therapeutic means.*PCR and JP have equal contribution in this work

Imipramine Can Be Effective on Depressive-Like Behaviors, but Not on Neurotrophic Factor Levels in an Animal Model for Bipolar Disorder Induced by Ouabain.

Despite possible risks of mania switching with the long-term use of antidepressants in patients with bipolar disorder (BD), these drugs may help in depressive episodes. Alterations in neurotrophic factor levels seem to be involved in the pathophysiology of BD. The present study aimed to evaluate the effect of acute treatment of imipramine on behavior and neurotrophic levels in rats submitted to the animal model for BD induced by ouabain. Wistar rats received a single intracerebroventricular (ICV) injection of artificial cerebrospinal fluid or ouabain (10-3M). Following the ICV administration, the rats were treated for 14days with saline (NaCl 0.9%, i.p.), lithium (47.5mg/kg, i.p.), or valproate (200mg/kg, i.p.). On the 13th and 14th days of treatment, the animals received an additional injection of saline or imipramine (10mg/kg, i.p.). Behavior tests were evaluated 7 and 14days after ICV injection. Adrenal gland weight and concentrations of ACTH were evaluated. Levels of neurotrophins BDNF, NGF, NT-3, and GDNF were measured in the frontal cortex and hippocampus by ELISA test. The administration of ouabain induced mania- and depressive-like behavior in the animals 7 and 14days after ICV, respectively. The treatment with lithium and valproate reversed the mania-like behavior. All treatments were able to reverse most of the depressive-like behaviors induced by ouabain. Moreover, ouabain increased HPA-axis parameters in serum and decreased the neurotrophin levels in the frontal cortex and hippocampus. All treatments, except imipramine, reversed these alterations. It can be suggested that acute administration of imipramine alone can be effective on depressive-like symptoms but not on neurotrophic factor alterations present in BD.

Effect of intrathecal administration of exogenous noggin on neuropathic pain.

To explore the effect of intrathecal administration of exogenous noggin (NOG) on the pain behavior in the neuropathic pain (NP) rats through L5 spinal nerve ligation (SNL), and to examine the regulative role of NOG in astrocyte activation, inflammatory cytokines and downstream signals. A total of 40 adult male Sprague Dawley (SD) rats were randomly divided into 3 groups: a control group (n=10), a SNL group (SNL+intrathecal injection of artificial cerebrospinal fluid, n=15), and a SNL+NOG group (SNL+intrathecal injection of recombinant NOG protein, n=15). Von-Frey filaments were used to test the changes of paw withdrawal threshold (PWT) at Day 1 before operation, and Day 1, Day 4, Day 7 and Day 14 after operation in each group. Immunofluorescence was used to observe the activation of astrocyte located in the dorsal horn of spinal cord in the 3 groups. Western blotting was conducted to detect the expression levels of glial fibrillary acidic protein (GFAP), interleukin-6 (IL-6), signal transducer and activator of transcription (STAT3) and phosphorylation STAT3 (p-STAT3). Compared with the control group, the PWT in the SNL group was markedly decreased at each time point, together with the increase in GFAP, IL-6 and the ratio of p-STAT3/STAT3 (all P<0.05). Meanwhile, compared with the SNL group, the PWT in the lumbar swelling of spinal cord in the SNL+NOG group was elevated at Day 4 and lasted to Day 14 (P<0.05), accompanied by the decrease in GFAP, IL-6 and the ratio of p-STAT3/STAT3 (all P<0.05). The intrathecal administration of NOG may alleviate NP in the SNL rats through inhibiting astrocyte activation and down-regulating the STAT3 signal pathway.

The α1-adrenergic receptors in the amygdala regulate the induction of learned despair through protein kinase C-beta signaling.

Hyperactivity of amygdala is observed in patients with major depressive disorder. Although the role of α1-adrenoceptor in amygdala on fear memory has been well studied, the role of α1-adrenoceptor in amygdala on depression-like behaviors remains unclear. Therefore, we investigated the effect of α1A-adrenoreceptor in amygdala on despair behavior, evaluated by the immobility time during tail suspension test (TST), pharmacological intervention, and immunohistological methods. C57BL6/J mice given a bilateral intra-amygdala injection of artificial cerebrospinal fluid exhibited an increased duration of immobility in the latter half of both trials of TST with a 24-h interval, a phenomenon known as learned despair. Intra-amygdala injection of WB4101 (1.7 nmol/0.1 µl), an α1 adrenoreceptor antagonist, but not propranolol (250 pmol/0.1 µl), a β-adrenoreceptor antagonist, blocked the induction of learned despair during TST. Immunostaining experiments revealed that ~61-75% of α1A-adrenoreceptor-positive neurons were colocalized with GAD65/67 in amygdala, implying that the α1-adrenoceptors in amygdala may enormously regulate the GABA release. Protein kinase C-beta (PKCβ) was predominantly expressed in the α1A-adrenoreceptor-positive neurons in the BLA, whereas protein kinase C-epsilon (PKCε) was highly expressed with the α1A-adrenoreceptor in the Central nucleus of amygdala. Intra-amygdala injection of ruboxistaurin (10 pmol/0.1 µl), a PKCβ inhibitor, blocked the induction of learned despair during TST, whereas neither TAT-εV1-2 (500 ng/0.1 μl), a cell-permeant PKCε inhibitory peptide, nor HBDDE (50 pmol/0.1 µl), an inhibitor of PKCα and -γ, affected the duration of immobility during TST. These data suggest that the α1-adrenoreceptor in amygdala regulates the induction of learned despair via PKCβ.

The Cataleptic, Asymmetric, Analgesic, and Brain Biochemical Effects of Parkinson's Disease Can Be Affected by Toxoplasma gondii Infection.

Purpose Parkinson's disease (PD) is a neurodegenerative disorder with progressive motor defects. Therefore, the aim of the present investigation was to examine whether catalepsy, asymmetry, and nociceptive behaviors; the Nissl-body and neuron distribution; brain-derived neurotrophic factor (BDNF); malondialdehyde (MDA); total antioxidant capacity (TAC) levels; and the percentage of dopamine depletion of striatal neurons in the rat model of Parkinson's disease (PD) can be affected by Toxoplasma gondii (TG) infection. Methods Fifty rats were divided into five groups: control (intact rats), sham (rats which received an intrastriatal injection of artificial cerebrospinal fluid (ACSF)), PD control (induction of PD without TG infection), TG control (rats infected by TG without PD induction), and PD infected (third week after PD induction, infection by TG was done). PD was induced by the unilateral intrastriatal microinjection of 6-hydroxydopamine (6-OHDA) and ELISA quantified dopamine, BDNF, MDA, and TAC in the striatum tissue. Cataleptic, asymmetrical, nociceptive, and histological alterations were determined by bar test, elevated body swing test, formalin test, and Nissl-body and neuron counting in the striatal neurons. Results The results demonstrated that PD could significantly increase the number of biased swings, descent latency time, and nociceptive behavior and decrease the distribution of Nissl-stained neurons compared to the control and sham groups. TG infection significantly improved biased swing, descent latency time, nociceptive behavior, and the Nissl-body distribution in striatal neurons in comparison to the PD control group. The striatal level of BDNF in the PD-infected and TG control groups significantly increased relative to the PD control group. The striatal MDA was significantly higher in the PD control than other groups, while striatal TAC was significantly lower in the PD control than other groups. Conclusions The current study indicates that TG infection could improve the cataleptic, asymmetric, nociceptive and behaviors; the level of striatal dopamine release; BDNF levels; TAC; and MDA in PD rats.

The Effects of Pregnancy on the Sympathoexcitatory and Pressor Responses to Nanoinjection of Angiotensin II into the Arcuate Nucleus

Pregnancy induces profound increases in sympathetic nerve activity (SNA). Angiotensin II (AngII) may contribute, since systemic or central blockade of AngII production or receptors (AT1aR) decreases SNA in pregnant animals. However, the brain sites involved are unknown. One possibility is the arcuate nucleus (ArcN), since AngII binds to ArcN AT1aR to increase SNA, and the ArcN is a well‐established reproductive integrating center. To begin to test this hypothesis, we measured the changes in SNA and mean arterial pressure (MAP) in response to bilateral nanoinjections of AngII (30 pmol in 30 nL) into the ArcN of α‐chloralose anesthetized pregnant rats and virgin rats throughout the estrus cycle. ArcN AngII slowly increased (P&lt;0.05) lumbar SNA (LSNA) in pregnant rats (by 50±10 % after 90 min; n=6), and the rise was larger than in proestrus rats (‐1±8 %; n=5; P&lt;0.05), similar to diestrus rats (40±9 %; n=4), but less than estrus rats (72±12 %; n=6; P&lt;0.05). ArcN AngII rapidly increased (P&lt;0.05) MAP by ~10 mmHg (after 10 min) in all groups, but after 90 min the increase was sustained (P&lt;0.05) only in pregnant (13±2 mmHg) and estrus (11±4 mmHg) rats. A cohort of ArcN neurons projects to and stimulates vasopressinergic neurons in the hypothalamic paraventricular and supraoptic nuclei. Therefore, to test if the initial or sustained increases in MAP were mediated by vasopressin, another set of estrus and pregnant rats were pretreated with the Manning Compound (V1x; 5 μg iv) 15 min before ArcN AngII. In estrus rats (n=4), V1x had no effects on baseline LSNA or MAP, but completely blocked the initial rise in MAP induced by ArcN AngII (2±3 mmHg). Nevertheless, the increase in MAP at 90 min was unchanged (13±3 mmHg; P&lt;0.05). The LSNA response to ArcN AngII (83±9 %) was also not altered. In pregnant rats pretreated with V1x (n=4), baseline MAP decreased (P&lt;0.05) by 10±1 mmHg, and again ArcN AngII failed to increase MAP initially (2±1 mmHg). However, the increase in MAP 90 min after ArcN AngII (7±2 mmHg) was the same as the increase 90 min after injection of artificial cerebrospinal fluid into the ArcN of V1x‐treated pregnant rats (5±2 mmHg). Again, the increase in LSNA to ArcN AngII was unchanged (30±6 %). Finally, RNAScope was used to assay AT1aR mRNA expression in the ArcN in diestrus, proestrus, and pregnant rats. ArcN AT1aR were undetectable in proestrus rats and were expressed at low but detectable levels in diestrus rats. In contrast, pregnancy markedly increased the expression of AT1aR in the ArcN. In summary, during pregnancy, ArcN AngII produces substantial increases in LSNA in association with elevated AT1aR expression. Moreover, the increase in MAP in response to ArcN AngII was reduced or eliminated in estrus and pregnant rats pretreated with a vasopressin V1 receptor blocker. In conclusion, these data highlight the ArcN as a potential site at which AngII increases SNA during normal pregnancy. The data also suggest that AngII can elicit an increase in vasopressin secretion via an action in the ArcN and that vasopressin contributes to the pressor responses induced by ArcN AngII in both estrus and pregnant rats.Support or Funding InformationHL128181

Subarachnoid Hemorrhage Induces Dynamic Immune Cell Reactions in the Choroid Plexus.

Subarachnoid hemorrhage (SAH) is a specific form of hemorrhagic stroke that frequently causes intracranial hypertension. The choroid plexus (CP) of the brain ventricles is responsible for producing cerebrospinal fluid and forms the blood – cerebrospinal fluid barrier. The aim of the current study was to determine whether SAH induces an immune cell reaction in the CP and whether the resulting increase in intracranial pressure (ICP) itself can lead to cellular changes in the CP. SAH was induced by injecting non-heparinized autologous blood to the cisterna magna. Artificial cerebrospinal fluid (ACSF) instead of blood was used to assess influence of increased ICP alone. SAH and ACSF animals were left to survive for 1, 3, and 7 days. SAH induced significantly increased numbers of M1 (ED1+, CCR7+) and M2 (ED2+, CD206+) macrophages as well as MHC-II+ antigen presenting cells (APC) compared to naïve and ACSF animals. Increased numbers of ED1+ macrophages and APC were found in the CP only 3 and 7 days after ACSF injection, while ED2+ macrophage number did not increase. CD3+ T cells were not found in any of the animals. Following SAH, proliferation activity in the CP gradually increased over time while ACSF application induced higher cellular proliferation only 1 and 3 days after injection. Our results show that SAH induces an immune reaction in the CP resulting in an increase in the number of several macrophage types in the epiplexus position. Moreover, we also found that increased ICP due to ACSF application induced both an immune reaction and increased proliferation of epiplexus cells in the CP. These findings indicate that increased ICP, and not just blood, contributes to cellular changes in the CP following SAH.

Effect of electroacupuncture on silent information regulator 1, fork head transcription factor O1 and proopiomelanocortin in the hypothalamus of rats with obesity induced by high-fat diet

To investigate the effect of electroacupuncture (EA) on silent information regulator 1 (SIRT1), forkhead transcription factor O1 (FoxO1), and proopiomelanocortin (POMC) in the hypothalamus of rats with high-fat diet-induced obesity (DIO), as well as the mechanism of EA in regulating central appetite peptides to help lose weight. Male Wistar rats were randomly divided into normal group, model group, EA group, EA＋inhibitor group, inhibitor group, and sham-operation group, with 10 rats in each group. High-fat diet was used to establish a rat model of DIO. The rats in the EA group and EA＋inhibitor group were given EA at "Fenglong" (ST40), "Zhongwan "(CV12)，"Guanyuan "(CV4), and"Zusanli" (ST36) with continuous wave at a frequency of 2 Hz and an intensity of 1 mA, for 10 minutes each time. The rats in the EA＋inhibitor group and inhibitor group were given tube placement in the third ventricle and injection of the specific SIRT1 antagonist EX-527. The rats in the sham-operation group were given tube placement in the third ventricle and injection of artificial cerebrospinal fluid. The above treatment was given 3 times a week for 8 weeks in total. Body weight, food intake, and Lee's index were observed before and after treatment. An automatic biochemical analyzer was used to measure the serum levels of total cholesterol (TC), triglyceride (TG), and free fatty acid (FFA), and Western blot was used to measure the protein expression of SIRT1, FoxO1, acetylated FoxO1(AC-FoxO1), and POMC in the hypothalamus. Before treatment, the model group, the EA group, the EA＋inhibitor group, the inhibitor group, and the sham-operation group had significantly higher body weight and food intake than the normal group (P<0.01), and the model group and the sham-operation group had a significantly higher Lee's index than the normal group (P<0.05). Compared with the model group after treatment, the EA group and the EA＋inhibitor group had significant reductions in body weight, food intake, TC, and the protein expression of AC-FoxO1 (P<0.01, P<0.05) and significant increases in the protein expression of SIRT1, FoxO1 and POMC (P<0.01, P<0.05); the EA group had significant reductions in Lee's index and the levels of TG, FFA(P<0.05，P<0.01)；the inhibitor group had significant increases in food intake, the serum levels of TC, TG, FFA(P<0.01) and significant reductions in the protein expression of SIRT1, FoxO1 and POMC (P<0.01，P<0.05). Compared with the EA group, the EA＋inhibitor group and the inhibitor group had significant increases in body weight, food intake, Lee's index, the levels of TG, FFA and the protein expression of AC-FoxO1 (P<0.01, P<0.05) and significant reductions in the protein expression of SIRT1, FoxO1 and POMC (P<0.01); the inhibitor group had significant increases in the serum levels of TC (P<0.01). Compared with the EA＋inhibitor group, the inhibitor group had significant increases in body weight, food intake, the serum levels of TC, TG, FFA, and the protein expression of AC-FoxO1 (P<0.01), as well as significant reductions in the protein expression of SIRT1, FoxO1 and POMC (P<0.01). In rats with DIO, EA can effectively up-regulate the expression of SIRT1 in the hypothalamus, exert a deacetylation effect on FoxO1, and promote the expression of the downstream appetite-inhibiting peptide POMC, which may be one of the mechanisms of EA to help lose weight by regulating central appetite peptides in the obesity model.

Gαq protein signaling in the bed nucleus of the stria terminalis regulate the lipopolysaccharide-induced despair-like behavior in mice.

Major depressive disorder (MDD) is highly comorbid with anxiety disorders. It has been reported that the bed nucleus of the stria terminalis (BNST) is important for the induction of anxiety and MDD. Recently, the Gαq protein signaling within the BNST is involved in the induction of anxiety through Gαq protein signaling-mediated RNA-editing of GluR2 subunit, which produces the calcium (Ca2+)-impermeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor. On the other hand, the role of Gαq protein signaling within the BNST on the induction of MDD has never been reported yet. Therefore, we investigated whether Gαq protein signaling-producing the Ca2+-impermeable AMPA receptors in the BNST is involved in the lipopolysaccharide (LPS)-induced depressive-like behavior, particularly, despair-like behavior. When mice were systemically challenged with a single dose of LPS (1.2 mg/kg, i.p.), the immobility time during tail suspension test (TST) was increased 24 h after LPS injection. However, pretreatment with bilateral intra-BNST injection of neomycin (6.5 mM, 0.125 µL/side), an inhibitor of phospholipase C that is activated by Gαq protein-coupled receptor stimulation, extended the LPS-induced increase in the immobility time of TST. Furthermore, the co-pretreatment with bilateral intra-BNST injection of neomycin with 1-naphthylacetyl spermine (3 mM, 0.125 µL/side), an antagonist of Ca2+-permeable AMPA receptor, to mimic one of the final forms of Gαq protein activation, abolished the aggravated effect of neomycin and significantly shortened the immobility time compared with the control mice with an intra-BNST injection of artificial cerebrospinal fluid before LPS injection. However, pretreatment with bilateral intra-BNST injection of MDL-12,330A (10 µM, 0.125 µL/side), an inhibitor of adenylyl cyclase that is activated by Gαs protein-coupled receptor stimulation, did not affect the LPS-induced increase in the immobility time of TST. These results indicate that the Gαq protein signaling-mediated RNA-editing of GluR2, which produces the Ca2+-impermeable AMPA receptors within the BNST, regulates the LPS-induced despair-like behavior.

Effects of Pretreatment With Ginseng Extract on Dopamine D2 Receptor Analgesia.

Introduction:The ginseng extract is an herb that has been used for many purposes such as analgesic effect. Dopamine D2 receptors are involved in the regulation of pain in humans. Therefore, the present investigation aims to study how pretreatment with aqueous-alcoholic extract of ginseng can affect dopamine D2 receptors’ pain sensitivity.Methods:We used 45 adult male rats weighing 250±20 for this study. Animals were maintained in a standard condition at a temperature of 21°C–24°C. The experimental groups were as follows: 1. Sham 1 (intraperitoneal [IP] injection of normal saline); 2. Sham 2 (intracerebroventricular [ICV] injection of artificial cerebrospinal fluid [ACSF]); 3. Experimental 1 (IP injection of ginseng extract); 4 and 5. Experimental groups 2 and 3 (IP injection of ginseng extract + bromocriptine 10 and 30 μg/rat by ICV injection); 6 and 7) experimental groups 4 and 5 (IP injection of ginseng extract + chlorpromazine 20 and 40 μg/rat by ICV injection). Ginseng extract 100 mg/kg/d was used for 7 days. Pain sensitivity test was done in all groups with the formalin test. Lateral ventricles of the rats were cannulated unilaterally by the stereotaxic procedure.Results:Our data showed that ginseng (100 mg/kg/d) significantly (P<0.05) decreased pain sensitivity compared to the sham 1 group. Bromocriptine in two doses significantly decreased pain sensitivity compared to the sham 2 group. Chlorpromazine in high doses significantly increased pain sensitivity compared to the sham 2 group.Conclusion:The present results indicate that ginseng can modulate the D2 receptor of the dopamine system in the control of pain sensitivity in the formalin test. Because bromocriptine and ginseng have similar effects, it seems that they had synergistic effects.

The Effects of Probiotic Lactobacillus and Bifidobacterium Strains on Memory and Learning Behavior, Long-Term Potentiation (LTP), and Some Biochemical Parameters in β-Amyloid-Induced Rat's Model of Alzheimer's Disease.

This study assessed the effects of probiotic supplementation on spatial learning and memory, long-term potentiation (LTP), paired-pulse facilitation (PPF) ratios, nitric oxide (NO) concentrations, and lipid profiles in a rat model of amyloid beta (Aβ)(1–42)-induced Alzheimer’s disease (AD). Forty rats were randomly divided into 4 groups. The sham (control and prevention) group received intracerebroventricular (ICV) injections of artificial cerebrospinal fluid, the Alzheimer group received ICV injection of Aβ(1–42), and the probiotic+Alzheimer group received 500 mg probiotics daily (15×109 colony-forming unit) by gavage for 4 weeks before and 2 weeks after injection of Aβ(1–42). The Morris water maze test was performed for evaluation of spatial learning and memory. LTP and PPF ratios were measured to evaluate longterm synaptic plasticity and pre-synaptic mechanisms, respectively. The results showed that probiotic supplementation significantly improved learning, but not memory impairment, and increased PPF ratios compared to those in the Alzheimer group. Both Aβ(1–42) injection and probiotic supplementation alone did not significantly effect plasma level of NO. Probiotic supplementation of rats in the probiotic (6 weeks)+Alzheimer group decreased serum levels of total cholesterol, triglyceride, and very low-density lipoprotein-cholesterol significantly compared to the Alzheimer group. The results of this study suggest that probiotic supplementation may positively impact learning capacity and LTP in rats with AD, most likely via the release of neurotransmitters via presynaptic mechanisms or via a protective effect on serum lipid profiles.

Inhibition of GSK-3β on Behavioral Changes and Oxidative Stress in an Animal Model of Mania.

The present study evaluated the effects of AR-A014418 on behavioral and oxidative stress parameters of rats submitted to the animal model of mania induced by ouabain (OUA). Wistar rats were submitted to stereotaxic surgery and received a single intracerebroventricular (ICV) injection of artificial cerebrospinal fluid (aCSF), OUA, or AR-A014418. After 7days, the animals were submitted to open-field test. After behavioral analysis, the brains were dissected in frontal cortex and hippocampus to the evaluation of oxidative stress. The OUA induced manic-like behavior in rats, which was reversed by AR-A014418 treatment. The ICV administration of OUA increases the levels of superoxide in submitochondrial particles, lipid hydroperoxide (LPH), 4-hydroxynonenal (4-HNE), 8-isoprostane, protein carbonyl, 3-nitrotyrosine, and activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) in both structures evaluated. In general, the treatment with AR-A014418 reversed these effects of OUA on the submitochondrial particles, LPH, 4-HNE, 8-isoprostane, protein carbonyl, 3-nitrotyrosine levels, and SOD activity. Furthermore, the injection of OUA decreased the catalase activity, and AR-A014418 promoted an increase in activity of this enzyme in the brain structures. These results suggest that GSK-3β inhibition can modulate manic-like behaviors. Also, it can be suggested that inhibition of GSK-3β can be effective against oxidative stress. However, more studies are needed to better elucidate these mechanisms. Graphical Abstract The effects of AR-A014418 on the behavioral and oxidative stress parameters in the animal model of mania induced by ouabain. Superoxide = superoxide production in submitochondrial particles; LPH = lipid hydroperoxide; 4-HNE = 4-hydroxynonenal; SOD = superoxide dismutase; GPx = glutathione peroxidase; GR = glutathione reductase.

Effect of intrathecal injection of bovineadrenalmedulla 8-22 on pain behavior in a mouse model of bone cancer pain

Objective To investigate the effect of intrathecal injection bovineadrenalmedulla 8-22 (BAM8-22) on pain behavior in a mouse model of bone cancer pain. Methods 50 male 8-10 week old C3H/HeJ mice weighing 18-22 g were divided randomly into 5 groups (n=8): sham group (S group), BCP group: artificial cerebrospinal fluid treat group(B0 group) and BAM8-22 treat groups (B1-B3 group). Group C and B were induced mouse models of bone cancer pain by intra-right-femur inoculations of osteolytic NCTC2472 cells while group S were injected only α-MEM. On the 14 d after inoculations, group S and BCP received intrathecal injection of artificial cerebrospinal fluid 5 μl, while group B1-B3 received intrathecal injection of BAM8-22 0.8, 2.4, 8.0 nmol, which dissolved in 5 μl artificial cerebrospinal fluid. They were intrathecally injected, respectively, once a day for 7 consecutive days starting from day 14 after inoculation. Mice received pain behavior tests including quantification of spontaneous flinches (NSF), paw withdrawal mechanical threshold (PWMT) 0.5 h before and at 2 h, after administration. Results Compared with S group [(1.80±0.20) times, (1.87±0.22) g], NSF [(14.67±2.65) times] was significantly increased (P=0.000) and MWT [(0.42±0.22) g] was significantly decreased (P=0.002) on 7-21 days after inoculation in BCP group. Compared with B0 group [(12.38±1.12) times, (0.48±0.22) g] and the basal level on 14th day before administration [(12.65±1.10) times, (0.46±0.19) g, P=0.012, 0.011, 0.001, 0.001], PWMT was significantly decreased, and NSF was increased at 2 h after administration in B2 group [(7.28±0.82) times, (1.01±0.13) g] and B3 groups [(4.18±1.02) times, (1.38±0.12) g, P=0.027, 0.025, 0.013, 0.009]. The analgesic effect of group B3 was more conspicuous compared with group B2 (P=0.007, 0.031). No obvious change of pain ethology indexes wag observed in group B1 [(12.03±1.22) times, (0.51±0.16) g] (P=0.096, 0.074, 0.527, 0.474). Conclusion Intrathecal BAM8-22 injection can effectively attenuated bone cancer pain with increased doses in the mouse model of bone cancer pain. Key words: Bone cancer pain; bovineadrenalmedulla 8-22; Behavior; Mouse

Arcuate Nucleus Angiotensin II Increases Arterial Pressure and Sympathetic Nerve Activity in Part via Inhibition of Neuropeptide Y Projections to the Hypothalamic Paraventricular Nucleus

Angiotensin II (AngII) acts centrally to increase arterial pressure (AP) and sympathetic nerve activity (SNA) mainly via AngII type 1 receptors (AT1R). Multiple brain areas have been identified as targets of AngII, including the arcuate nucleus (ArcN). However, the neural pathway that mediates AngII actions in the ArcN remains unknown. Recent studies suggest that AT1R expression in the ArcN is restricted to Neuropeptide Y (NPY) neurons, which project to the hypothalamic paraventricular nucleus (PVN). Therefore, we hypothesized that, in the ArcN, AngII increases AP and SNA in part by suppressing the activity of tonically sympathoinhibitory NPY neurons that innervate the PVN. To test this hypothesis, in α‐chloralose anesthetized male SD rats, we determined if blockade of PVN NPY Y1 receptors (Y1R) with bilateral nanoinjections of BIBO3304 (60 pmol/60nL) elicits smaller increases in AP and SNA 60 min after nanoinjection of exogenous AngII into the ArcN, compared to 60 min after ArcN injections of artificial cerebrospinal fluid (aCSF). As we reported before, after ArcN aCSF, blockade of PVN Y1R increased (n=3; all P&lt;0.05) mean AP (MAP, 99±4 to 111± 4 mmHg), lumbar SNA (LSNA, 99±9 to 130±12 % control) and splanchnic SNA (SSNA, 105±9 to 142±10 % control). Bilateral nanoinjection of AngII into the ArcN slowly increased (n=4; all P&lt;0.05) MAP (101±4 to 116±3 mmHg), LSNA (100 to 153±10 % control) and SSNA (100 to 151±6 % control). However, 60 min after ArcN AngII, blockade of PVN Y1R did not further increase MAP (to 122±2 mmHg), LSNA (to 174±17 % control), and SSNA (to 176±22 % control), compared to the changes observed after PVN aCSF injections (ArcN AngII+PVN aCSF: n=5; MAP, 120±4 to 123±3 mmHg; LSNA, 160±20 to 174±22 % control; SSNA, 172±21 to 193±20 % control). In summary, ArcN injections of AngII markedly attenuated the pressor and sympathoexcitatory effects of blockade of PVN NPY Y1R. Therefore, we conclude that ArcN AngII increases MAP, LSNA, and SSNA, in part, via inhibition of NPY neuronal projections to the PVN.Support or Funding InformationSupported in part by NIH HL128181.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Hypothalamic PVN contributes to acute intermittent hypoxia-induced sympathetic but not phrenic long-term facilitation.

Blackburn MB, Andrade MA, Toney GM. Hypothalamic PVN contributes to acute intermittent hypoxia-induced sympathetic but not phrenic long-term facilitation. J Appl Physiol 124: 1233-1243, 2018. First published December 19, 2017; doi: 10.1152/japplphysiol.00743.2017 .- Acute intermittent hypoxia (AIH) repetitively activates the arterial chemoreflex and triggers a progressive increase of sympathetic nerve activity (SNA) and phrenic nerve activity (PNA) referred to as sympathetic and phrenic long-term facilitation (S-LTF and P-LTF), respectively. Neurons of the hypothalamic paraventricular nucleus (PVN) participate in the arterial chemoreflex, but their contribution to AIH-induced LTF is unknown. To determine this, anesthetized rats were vagotomized and exposed to 10 cycles of AIH, each consisting of ventilation for 3 min with 100% O2 followed by 3 min with 15% O2. Before AIH, rats received bilateral PVN injections of artificial cerebrospinal fluid (aCSF; vehicle) or the GABA-A receptor agonist muscimol (100 pmol in 50 nl) to inhibit neuronal activity. Thirty minutes after completing the AIH protocol, during which rats were continuously ventilated with 100% O2, S-LTF and P-LTF were quantified from recordings of integrated splanchnic SNA and PNA, respectively. PVN muscimol attenuated increases of SNA during hypoxic episodes occurring in later cycles (6-10) of AIH ( P < 0.03) and attenuated post-AIH S-LTF ( P < 0.001). Muscimol, however, did not consistently affect peak PNA responses during hypoxic episodes and did not alter AIH-induced P-LTF. These findings indicate that PVN neuronal activity contributes to sympathetic responses during AIH and to subsequent generation of S-LTF. NEW & NOTEWORTHY Neural circuits mediating acute intermittent hypoxia (AIH)-induced sympathetic and phrenic long-term facilitation (LTF) have not been fully elucidated. We found that paraventricular nucleus (PVN) inhibition attenuated sympathetic activation during episodes of AIH and reduced post-AIH sympathetic LTF. Neither phrenic burst patterning nor the magnitude of AIH-induced phrenic LTF was affected. Findings indicate that PVN neurons contribute to AIH-induced sympathetic LTF. Defining mechanisms of sympathetic LTF could improve strategies to reduce sympathetic activity in cardiovascular and metabolic diseases.

Effects of sodium butyrate on aversive memory in rats submitted to sepsis

Epigenetic mechanisms are involved in normal behavior and are implicated in several brain neurodegenerative conditions, psychiatric and inflammatory diseases as well. Moreover, it has been demonstrated that sepsis lead to an imbalance in acetylation of histones and that histone deacetylase inhibitors (HDACi) can reverse this condition. In the present study, we evaluated the effects of a microinjection of sodium butyrate (SB, HDACi) into cerebral ventricle on aversive memory in rats submitted to the sepsis. Rats were given a single intraventricular injection of artificial cerebrospinal fluid (ACSF) or SB and immediately after the stereotaxic surgery and the drug infusion, the animals were subjected to cecal ligation and perforation (CLP). The animals were killed twenty four hours or ten days after sepsis induction and the prefrontal cortex, hippocampus, striatum and cortex were obtained to the determination of histone deacetylase activity. In a separate cohort of animals 10 days after sepsis induction, it was performed the inhibitory avoidance task. SB administration was able to reverse the impairment in aversive memory and inhibited the HDAC activity in prefrontal cortex and hippocampus 10 days after CLP. These support a role for an epigenetic mechanism in the long-term cognitive impairments observed in sepsis survivors animals.

Silibinin ameliorates LPS-induced memory deficits in experimental animals

Neuroinflammation is considered as one of the predisposing factor in the etiology of several neurodegenerative disorders. Therefore, the objective of the present study was to evaluate the protective effect of silibinin (SIL) in the lipopolysaccharide (LPS)-induced neuroinflammatory model. The effect of SIL on memory function was also evaluated on normal rats without LPS administration. In the first experiment, male rats were divided into five groups. Except control group animals, all rats received bilateral intracerebroventricular injection of LPS (5μg/5μl) into lateral ventricles on the first day of the experimental schedule. Control rats received bilateral intracerebroventricular injection of artificial cerebrospinal fluid into lateral ventricles. SIL in doses of 50, 100 and 200mg/kg, p.o. was administered 1h before LPS injection and continued for 7days. On Day-7, SIL attenuated the LPS-induced long-term and working memory loss in elevated plus and Y-maze test respectively. Further, SIL dose-dependently attenuated LPS-induced decrease in acetylcholine level and increase in the acetylcholinestrase activity in hippocampus and pre-frontal cortex. SIL ameliorated LPS-induced decrease in the mitochondrial complex activity (I, IV and V) and integrity, increase in lipid peroxidation and decrease in the activity of superoxide dismutase in both the brain regions. SIL attenuated amyloidogenesis in the hippocampus, while it decreased the LPS-induced increase in the level of NFκB in the pre-frontal cortex. In another study, SIL dose-dependently, enhanced memory functions in the normal rats, indicating its nootropic activity. Hence, SIL could be a potential candidate in the management of neuroinflammation-related memory disorders.

Predator odor-evoked BOLD activation in the awake rat: Modulation by oxytocin and V1a vasopressin receptor antagonists

Modulators of unconditioned fear are potential targets for developing treatments for anxiety disorders. We used blood oxygen level dependent (BOLD) MRI to investigate the pattern of brain activity during the presentation of a predator odor (cat fur) and a repulsive novel odor, butyric acid (BA), to awake rats. We further tested whether odor-evoked BOLD activation involved oxytocin (OT) and vasopressin V1a receptors. Animals were subdivided into groups either administered an intracerebroventricular injection of artificial cerebrospinal fluid (CSF), an OT receptor antagonist or a V1a antagonist (125ng/10μL each) 90min before studies. BA odor evoked robust brain activation across olfactory, sensory, memory and limbic regions. The magnitude of BOLD activation across these regions was greater for BA than with cat fur. However, blockade of OT and V1a receptors differentially modulated odor evoked neural activity, particularly in the amygdala. OT and V1a antagonism preferentially modulated BOLD responding to BA in the cortical amygdala. While, OT and V1a antagonisms preferentially modulated BOLD responding to cat fur in the central amygdala. The data suggest that although OT receptors modulate BOLD activation in response to a novel and repulsive odor such as BA, vasopressin V1a receptors exert a modulatory influence on the neural response to a predator odor.

Herkinorin dilates cerebral vessels via kappa opioid receptor and cyclic adenosine monophosphate (cAMP) in a piglet model

Since herkinorin is the first non-opioid mu agonist derived from salvinorin A that has the ability to induce cerebral vascular dilatation, we hypothesized that herkinorin could have similar vascular dilatation effect via the mu and kappa opioid receptors and the cAMP pathway. The binding affinities of herkinorin to kappa and mu opioid receptors were determined by in-vitro competition binding assays. The cerebral arteries were monitored in piglets equipped with a closed cranial window and the artery responses were recorded before and every 30s after injection of artificial cerebrospinal fluid (CSF) in the presence or absence of the investigated drugs: herkinorion, norbinaltorphimine (NTP), a kappa opioid receptor antagonist, β-funaltrexamine (β-FNA), a mu opioid receptor antagonist, or Rp-8-Br-cAMPS (Rp-cAMPS), an inhibitor of protein kinase A (PKA). CSF samples were collected before and 10min after herkinorin and NTP administration for the measurement of cAMP levels. Data were analyzed by repeated-measures analysis of variance. Our results show that herkinorin binds to both kappa and mu opioid receptors. Its vasodilation effect is totally abolished by NTP, but is not affected by β-FNA. The levels of cAMP in the CSF elevate after herkinorin administration, but are abolished with NTP administration. The cerebral vasodilative effect of herkinorin is also blunted by Rp-cAMPS. In conclusion, as a non-opioid kappa and mu opioid receptor agonist, herkinorin exhibits cerebral vascular dilatation effect. The dilatation is mediated though the kappa opioid receptor rather than the mu opioid receptor. cAMP signaling also plays an important role in this process.