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1.
Anesthesiology ; 133(4): 852-866, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32930727

RESUMO

BACKGROUND: Cognitive deficits after perinatal anesthetic exposure are well established outcomes in animal models. This vulnerability is sex-dependent and associated with expression levels of the chloride transporters NKCC1 and KCC2. The hypothesis was that androgen signaling, NKCC1 function, and the age of isoflurane exposure are critical for the manifestation of anesthetic neurotoxicity in male rats. METHODS: Flutamide, an androgen receptor antagonist, was administered to male rats on postnatal days 2, 4, and 6 before 6 h of isoflurane on postnatal day 7 (ntotal = 26). Spatial and recognition memory were subsequently tested in adulthood. NKCC1 and KCC2 protein levels were measured from cortical lysates by Western blot on postnatal day 7 (ntotal = 20). Bumetanide, an NKCC1 antagonist, was injected immediately before isoflurane exposure (postnatal day 7) to study the effect of NKCC1 inhibition (ntotal = 48). To determine whether male rats remain vulnerable to anesthetic neurotoxicity as juveniles, postnatal day 14 animals were exposed to isoflurane and assessed as adults (ntotal = 30). RESULTS: Flutamide-treated male rats exposed to isoflurane successfully navigated the spatial (Barnes maze probe trial F[1, 151] = 78; P < 0.001; mean goal exploration ± SD, 6.4 ± 3.9 s) and recognition memory tasks (mean discrimination index ± SD, 0.09 ± 0.14; P = 0.003), unlike isoflurane-exposed controls. Flutamide changed expression patterns of NKCC1 (mean density ± SD: control, 1.49 ± 0.69; flutamide, 0.47 ± 0.11; P < 0.001) and KCC2 (median density [25th percentile, 75th percentile]: control, 0.23 [0.13, 0.49]; flutamide, 1.47 [1.18,1.62]; P < 0.001). Inhibiting NKCC1 with bumetanide was protective for spatial memory (probe trial F[1, 162] = 6.6; P = 0.011; mean goal time, 4.6 [7.4] s). Delaying isoflurane exposure until postnatal day 14 in males preserved spatial memory (probe trial F[1, 140] = 28; P < 0.001; mean goal time, 6.1 [7.0] s). CONCLUSIONS: Vulnerability to isoflurane neurotoxicity is abolished by blocking the androgen receptor, disrupting the function of NKCC1, or delaying the time of exposure to at least 2 weeks of age in male rats. These results support a dynamic role for androgens and chloride transporter proteins in perinatal anesthetic neurotoxicity.


Assuntos
Anestésicos Inalatórios/toxicidade , Isoflurano/toxicidade , Receptores Androgênicos/fisiologia , Membro 2 da Família 12 de Carreador de Soluto/fisiologia , Fatores Etários , Antagonistas de Receptores de Andrógenos/farmacologia , Animais , Animais Recém-Nascidos , Feminino , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Ratos , Ratos Sprague-Dawley , Fatores Sexuais
2.
Nat Commun ; 11(1): 3012, 2020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-32541656

RESUMO

The complex relationship between specific hippocampal oscillation frequency deficit and cognitive dysfunction in the ischemic brain is unclear. Here, using a mouse two-vessel occlusion (2VO) cerebral ischemia model, we show that visual stimulation with a 40 Hz light flicker drove hippocampal CA1 slow gamma and restored 2VO-induced reduction in CA1 slow gamma power and theta-low gamma phase-amplitude coupling, but not those of the high gamma. Low gamma frequency lights at 30 Hz, 40 Hz, and 50 Hz, but not 10 Hz, 80 Hz, and arrhythmic frequency light, were protective against degenerating CA1 neurons after 2VO, demonstrating the importance of slow gamma in cognitive functions after cerebral ischemia. Mechanistically, 40 Hz light flicker enhanced RGS12-regulated CA3-CA1 presynaptic N-type calcium channel-dependent short-term synaptic plasticity and associated postsynaptic long term potentiation (LTP) after 2VO. These results support a causal relationship between CA1 slow gamma and cognitive dysfunctions in the ischemic brain.


Assuntos
Região CA1 Hipocampal/fisiologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Ritmo Gama/fisiologia , Plasticidade Neuronal/fisiologia , Neurônios/fisiologia , Animais , Isquemia Encefálica/fisiopatologia , Região CA1 Hipocampal/irrigação sanguínea , Circulação Cerebrovascular/fisiologia , Estimulação Elétrica , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Atividade Motora/fisiologia , Estimulação Luminosa
3.
Psychopharmacology (Berl) ; 237(7): 2089-2101, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32494972

RESUMO

RATIONALE: Approximately 20-40% of patients with cancer will experience brain metastasis (BM), which has a great impact on the quality of life and survival rates of patients. Whole brain radiotherapy (WBRT) is an effective method for the treatment of BM. However, it cannot be ignored that WBRT might induce a series of neuropsychiatric side effects, including cognitive dysfunction (CD). Accumulating evidence shows that the gut microbiota and the gut-microbiota-brain axis may play a vital role in the pathogenesis of CD. OBJECTIVE AND METHODS: We adopted WBRT to mimic CD after a hierarchical cluster analysis of the Morris water maze test (MWMT) results. In addition, we observed the effects of antibiotics and prebiotics on WBRT-induced CD. Variations were revealed via the 16S rRNA sequencing analysis at different levels. RESULTS: The 16S rRNA sequencing analysis revealed an altered composition of gut microbiota between CD and non-CD phenotypes. Furthermore, we observed a decrease in the levels of Phylum-Bacteroidete, Class-Bacteroidia, and Order-Bacteroidales in the CD group and an increase in the Genus-Allobaculum level after WBRT. Pretreatment with antibiotics caused a significant decrease in the level of Phylum-TM7 01, whereas an increase in the levels of Class-Gammaproteobacteria, Order-Enterobacteriales, and Species-Escherichia coli. After pretreatment with probiotics, the levels of Phylum-Cyanobacteria, Class-4C0d-2, and Order-YS2 were decreased, while the levels of Family-Bacteroidaceae, Genus-Bacteroides, and Species-Parabacteroides distasonis were increased. CONCLUSIONS: WBRT-induced CD might be highly related to abnormal composition of gut microbiota. Strategies improving the composition of the gut microbiota may provide beneficial effects on CD in individuals exposed to WBRT.


Assuntos
Encéfalo/fisiologia , Encéfalo/efeitos da radiação , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/microbiologia , Microbioma Gastrointestinal/fisiologia , Microbioma Gastrointestinal/efeitos da radiação , Animais , Encéfalo/efeitos dos fármacos , Disfunção Cognitiva/psicologia , Microbioma Gastrointestinal/efeitos dos fármacos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Aprendizagem em Labirinto/efeitos da radiação , Camundongos , Camundongos Endogâmicos C57BL , Prebióticos/administração & dosagem , Probióticos/administração & dosagem
4.
Life Sci ; 255: 117828, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32454160

RESUMO

AIMS: To explore the role of chemokine CC motif ligand 2 (CCL2) in spatial memory and cognition impairment, and the underlying mechanisms focused on inflammatory, glutamate metabolistic and apoptotic- associated mRNA expression. MATERIALS AND METHODS: Stereotaxic surgery was performed here to establish a rat model by bilateral intra-hippocampal injection of CCL2. Morris water maze (MWM) and Novel object recognition test (NORT) were used to assess the learning, memory and cognitive ability respectively. RT-PCR was used to detect the relative mRNA expression of inflammatory, glutamate metabolistic and apoptotic- associated indexes. Nissl and TUNEL staining were performed to observe the morphological changes of hippocampal CA1 zone and quantified the apoptosis of hippocampal neurons of CA1 zones respectively. KEY FINDINGS: We found CCL2 injured cognitive function in rats. Six days after CCL2 injection, we revealed the following obvious mRNA expression changes: (1) increasing of the neuroinflammatory cytokines IL-1ß, CXCL-10, IL-6; (2) decreasing of the glutamate transporters GLT-1 and GLAST and increasing of PAG; (3) increasing of the apoptotic genes caspase-8, caspase-3 and Bax, while decreasing the anti-apoptotic gene Bcl-2. Further, Nissl staining and TUNEL confirmed the injury of the structure of hippocampal CA1 zones and the apoptosis of hippocampal neurons. SIGNIFICANCE: Our results indicated that CCL2 impaired spatial memory and cognition, the involving mechanisms may link to the up-regulation of mRNA expression of the three major pathological events: inflammation, excitotoxicity and neuronal apoptosis, which were involved in HIV-associated neurocognitive disorder (HAND). Taken together, these findings suggest a potential therapeutic strategy against CCL2.


Assuntos
Quimiocina CCL2/metabolismo , Infecções por HIV/complicações , Inflamação/patologia , Transtornos da Memória/fisiopatologia , Transtornos Neurocognitivos/fisiopatologia , Animais , Apoptose/fisiologia , Quimiocina CCL2/administração & dosagem , Cognição/fisiologia , Modelos Animais de Doenças , Ácido Glutâmico/metabolismo , Hipocampo/patologia , Masculino , Aprendizagem em Labirinto/fisiologia , Transtornos Neurocognitivos/virologia , Neurônios/patologia , Ratos , Ratos Sprague-Dawley , Memória Espacial/fisiologia
5.
Nature ; 580(7805): 647-652, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32350463

RESUMO

Neurodevelopment is characterized by rapid rates of neural cell proliferation and differentiation followed by massive cell death in which more than half of all recently generated brain cells are pruned back. Large amounts of DNA damage, cellular debris, and by-products of cellular stress are generated during these neurodevelopmental events, all of which can potentially activate immune signalling. How the immune response to this collateral damage influences brain maturation and function remains unknown. Here we show that the AIM2 inflammasome contributes to normal brain development and that disruption of this immune sensor of genotoxic stress leads to behavioural abnormalities. During infection, activation of the AIM2 inflammasome in response to double-stranded DNA damage triggers the production of cytokines as well as a gasdermin-D-mediated form of cell death known as pyroptosis1-4. We observe pronounced AIM2 inflammasome activation in neurodevelopment and find that defects in this sensor of DNA damage result in anxiety-related behaviours in mice. Furthermore, we show that the AIM2 inflammasome contributes to central nervous system (CNS) homeostasis specifically through its regulation of gasdermin-D, and not via its involvement in the production of the cytokines IL-1 and/or IL-18. Consistent with a role for this sensor of genomic stress in the purging of genetically compromised CNS cells, we find that defective AIM2 inflammasome signalling results in decreased neural cell death both in response to DNA damage-inducing agents and during neurodevelopment. Moreover, mutations in AIM2 lead to excessive accumulation of DNA damage in neurons as well as an increase in the number of neurons that incorporate into the adult brain. Our findings identify the inflammasome as a crucial player in establishing a properly formed CNS through its role in the removal of genetically compromised cells.


Assuntos
Encéfalo/crescimento & desenvolvimento , Dano ao DNA , Proteínas de Ligação a DNA/metabolismo , Inflamassomos/metabolismo , Animais , Animais Recém-Nascidos , Ansiedade/patologia , Ansiedade/fisiopatologia , Ansiedade/psicologia , Comportamento Animal/fisiologia , Encéfalo/citologia , Encéfalo/metabolismo , Encéfalo/patologia , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Caspase 1/deficiência , Caspase 1/metabolismo , Morte Celular , Proteínas de Ligação a DNA/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Mutação , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Neurônios/patologia , Proteínas de Ligação a Fosfato/metabolismo
6.
Psychopharmacology (Berl) ; 237(7): 1989-2005, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32388619

RESUMO

RATIONALE: Abuse of the psychostimulant methamphetamine (METH) can cause long-lasting damage to brain monoaminergic systems and is associated with profound mental health problems for users, including lasting cognitive impairments. Animal models of METH exposure have been useful in dissecting the molecular effects of the drug on cognition, but many studies use acute, non-contingent "binge" administrations of METH which do not adequately approximate human METH use. Long-term METH exposure via long-access (LgA) self-administration paradigms has been proposed to more closely reflect human use and induce cognitive impairments. OBJECTIVE: To better understand the role of contingency and patterns of exposure in METH-induced cognitive impairments, we analyzed behavioral and neurochemical outcomes in adult male rats, comparing non-contingent "binge" METH administration with contingent (LgA) METH self-administration and non-contingent yoked partners. RESULTS: Binge METH (40 mg/kg, i.p., over 1 day) dramatically altered striatal and hippocampal dopamine, DOPAC, 5-HT, 5-HIAA, BDNF, and TrkB 75 days after drug exposure. In contrast, 6-h LgA METH self-administration (cumulative 24.8-48.9 mg METH, i.v., over 16 days) altered hippocampal BDNF in both contingent and yoked animals but reduced striatal 5-HIAA in only contingent animals. Neurochemical alterations following binge METH administration were not accompanied by cognitive deficits in Morris water maze, novel object recognition, or Y-maze tests. However, contingent LgA METH self-administration resulted in impaired spatial memory in the water maze. CONCLUSIONS: Overall, substantial differences in neurochemical markers between METH exposure and self-administration paradigms did not consistently translate to deficits in cognitive tasks, highlighting the complexity of correlating METH-induced neurochemical changes with cognitive outcomes.


Assuntos
Estimulantes do Sistema Nervoso Central/administração & dosagem , Cognição/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Aprendizagem em Labirinto/efeitos dos fármacos , Metanfetamina/administração & dosagem , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Animais , Cognição/fisiologia , Dopamina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Ácido Hidroxi-Indolacético/metabolismo , Masculino , Aprendizagem em Labirinto/fisiologia , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/metabolismo , Ratos , Ratos Wistar , Autoadministração/psicologia
7.
J Neurosci ; 40(25): 4888-4899, 2020 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-32376783

RESUMO

Age-related cognitive impairments are associated with differentially expressed genes (DEGs) linked to defined neural systems; however, studies examining multiple regions of the hippocampus fail to find links between behavior and transcription in the dentate gyrus (DG). We hypothesized that use of a task requiring intact DG function would emphasize molecular signals in the DG associated with a decline in performance. We used a water maze beacon discrimination task to characterize young and middle-age male F344 rats, followed by a spatial reference memory probe trial test. Middle-age rats showed increased variability in discriminating two identical beacons. Use of an allocentric strategy and formation of a spatial reference memory were not different between age groups; however, older animals compensated for impaired beacon discrimination through greater reliance on spatial reference memory. mRNA sequencing of hippocampal subregions indicated DEGs in the DG of middle-age rats, linked to synaptic function and neurogenesis, correlated with beacon discrimination performance, suggesting that senescence of the DG underlies the impairment. Few genes correlated with spatial memory across age groups, with a greater number in region CA1. Age-related CA1 DEGs, correlated with spatial memory, were linked to regulation of neural activity. These results indicate that the beacon task is sensitive to impairment in middle age, and distinct gene profiles are observed in neural circuits that underlie beacon discrimination performance and allocentric memory. The use of different strategies in older animals and associated transcriptional profiles could provide an animal model for examining cognitive reserve and neural compensation of aging.SIGNIFICANCE STATEMENT Hippocampal subregions are thought to differentially contribute to memory. We took advantage of age-related variability in performance on a water maze beacon task and next-generation sequencing to test the hypothesis that aging of the dentate gyrus is linked to impaired beacon discrimination and compensatory use of allocentric memory. The dentate gyrus expressed synaptic function and neurogenesis genes correlated with beacon discrimination in middle-age animals. Spatial reference memory was associated with CA1 transcriptional correlates linked to regulation of neural activity and use of an allocentric strategy. This is the first study examining transcriptomes of multiple hippocampal subregions to link age-related impairments associated with discrimination of feature overlap and alternate response strategies to gene expression in specific hippocampal subregions.


Assuntos
Envelhecimento Cognitivo/fisiologia , Giro Denteado/fisiologia , Hipocampo/fisiologia , Transcriptoma , Animais , Aprendizagem em Labirinto/fisiologia , Ratos , Ratos Endogâmicos F344 , Memória Espacial/fisiologia
8.
Psychopharmacology (Berl) ; 237(8): 2317-2326, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32382782

RESUMO

RATIONALE: Prolinol aryl ethers and their rigidified analogues pyrrolidinyl benzodioxanes have a high affinity for mammalian α4ß2 nicotinic acetylcholine receptors (nAChRs). Electrophysiological studies have shown that the former are full agonists and the latter partial agonists or antagonists of human α4ß2 receptors, but their in vivo effects are unknown. OBJECTIVES AND METHODS: As α4ß2 nAChRs play an important role in the cognition and the rewarding effects of nicotine, we tested the effects of two full agonists and one antagonist on spatial learning, memory and attention in zebrafish using a T-maze task and virtual object recognition test (VORT). The effect of a partial agonist in reducing nicotine-induced conditioned place preference (CPP) was also investigated. RESULTS: In comparison with the vehicle alone, the full agonists MCL-11 and MCL-28 induced a significant cognitive enhancement as measured by the reduced running time in the T-maze and increased attention as measured by the increased discrimination index in the VORT. MCL-11 was 882 times more potent than nicotine. The two compounds were characterised by an inverted U-shaped dose-response curve, and their effects were blocked by the co-administration of the antagonist MCL-117, which alone had no effect. The partial agonist MCL-54 induced CPP and had an inverted U-shaped dose-response curve similar to that of nicotine but blocked the reinforcing effect of co-administered nicotine. Binding studies showed that all of the compounds have a higher affinity for heteromeric [3H]-epibatidine receptors than [125I]-αBungarotoxin receptors. MCL-11 was the most selective of heteromeric receptors. CONCLUSIONS: These behavioural studies indicate that full agonist prolinol aryl ethers are very active in increasing spatial learning, memory and attention in zebrafish. The benzodioxane partial agonist MCL-54 reduced nicotine-induced CPP, and the benzodioxane antagonist MCL-117 blocked all agonist-induced activities.


Assuntos
Aprendizagem em Labirinto/efeitos dos fármacos , Agonistas Nicotínicos/metabolismo , Antagonistas Nicotínicos/metabolismo , Pirrolidinas/metabolismo , Receptores Nicotínicos/metabolismo , Animais , Relação Dose-Resposta a Droga , Éteres/metabolismo , Éteres/farmacologia , Feminino , Masculino , Aprendizagem em Labirinto/fisiologia , Morfinanos/metabolismo , Morfinanos/farmacologia , Nicotina/metabolismo , Nicotina/farmacologia , Agonistas Nicotínicos/farmacologia , Antagonistas Nicotínicos/farmacologia , Pirrolidinas/farmacologia , Pirrolidinonas/metabolismo , Pirrolidinonas/farmacologia , Peixe-Zebra
9.
Psychopharmacology (Berl) ; 237(8): 2327-2343, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32399631

RESUMO

RATIONALE: The c-Jun N-terminal kinase (JNK) pathway and neurotrophic factor dysregulation play a critical role in the pathogenesis of neurobehavioral disorders (anxiety and depression). Targeting the JNK pathway and BDNF/VEGF signaling may signify a new avenue for the treatment of neurobehavioral disorders. OBJECTIVES: The present study investigated the effect of matrine (Mat) against anxiety- and depressive-like emotional status in an acute mouse model of burn injury and explores its underlying mechanism. METHODS: In the mouse model of thermal injury, anxiety- and depression-related behaviors were evaluated using the elevated plus-maze test, the light-dark box test, the open-field test, the forced swimming test, and the tail suspension test. The JNK/caspase-3 and BDNF/VEGF proteins were determined by immunohistochemistry. Additionally, proinflammatory cytokine, antioxidant, nitric oxide, and corticosterone levels were also measured. RESULTS: The results showed that treatment with Mat significantly improves anxiety- and depressive-like behaviors. It remarkably reduced the levels of proinflammatory cytokines, malondialdehyde, and nitric oxide in the hippocampus and prefrontal cortex of a mouse brain. It considerably improved burn-induced alteration in the antioxidant status, corticosterone, and BDNF/VEGF. It also inhibited burn-induced apoptotic signaling by downregulating the expression of JNK/caspase-3. Similarly, it prevented DNA damage and histopathological changes in the dentate gyrus of the hippocampus. Furthermore, molecular docking results showed that Mat possess better binding affinity for JNK/caspase-3 and BDNF/VEGF proteins. CONCLUSIONS: These findings provide convincing evidence that Mat improves anxiety- and depressive-like emotional status through modulation of JNK-mediated inflammatory, oxidative stress, apoptotic, and BDNF/VEGF signaling in an acute mouse model of burn injury.


Assuntos
Alcaloides/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Queimaduras/metabolismo , Caspase 3/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Quinolizinas/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Alcaloides/farmacologia , Alcaloides/uso terapêutico , Animais , Ansiolíticos/metabolismo , Ansiolíticos/farmacologia , Ansiolíticos/uso terapêutico , Ansiedade/tratamento farmacológico , Ansiedade/metabolismo , Fator Neurotrófico Derivado do Encéfalo/antagonistas & inibidores , Queimaduras/tratamento farmacológico , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Camundongos , Simulação de Acoplamento Molecular/métodos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Quinolizinas/farmacologia , Quinolizinas/uso terapêutico , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores
10.
Nat Neurosci ; 23(5): 651-663, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32251386

RESUMO

The brain codes continuous spatial, temporal and sensory changes in daily experience. Recent studies suggest that the brain also tracks experience as segmented subdivisions (events), but the neural basis for encoding events remains unclear. Here, we designed a maze for mice, composed of four materially indistinguishable lap events, and identify hippocampal CA1 neurons whose activity are modulated not only by spatial location but also lap number. These 'event-specific rate remapping' (ESR) cells remain lap-specific even when the maze length is unpredictably altered within trials, which suggests that ESR cells treat lap events as fundamental units. The activity pattern of ESR cells is reused to represent lap events when the maze geometry is altered from square to circle, which suggests that it helps transfer knowledge between experiences. ESR activity is separately manipulable from spatial activity, and may therefore constitute an independent hippocampal code: an 'event code' dedicated to organizing experience by events as discrete and transferable units.


Assuntos
Região CA1 Hipocampal/fisiologia , Aprendizagem em Labirinto/fisiologia , Neurônios/fisiologia , Animais , Camundongos
11.
Psychopharmacology (Berl) ; 237(7): 2103-2110, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32303779

RESUMO

RATIONALE: Effort-related choice tasks are used to study aspects of motivation in both rodents and humans (Der-Avakian and Pizzagalli Biol Psychiatry 83(11):932-939, 2018). Various dopaminergic manipulations and antidepressant treatments can shift responding to these tasks (Randall et al. Int J Neuropsychopharmacol 18(2), 2014; Yohn et al. Psychopharmacology 232(7):1313-1323, 2015). However, while chronic stress can precipitate mood disorders in humans, there is relatively little known about whether chronic stress elicits maladaptive behaviors in rodent effort-related choice tasks. OBJECTIVES: Chronic corticosterone (CORT) elicits an increase in negative maladaptive behaviors in male mice (David et al. Neuron 62(4):479-493, 2009; Gourley et al. Biol Psychiatry 64(10):884-890, 2008; Olausson et al. Psychopharmacology 225(3):569-577, 2013). We hypothesized that chronic CORT administration to male mice would reduce motivation for a higher effort, higher reward option, and shift responding to a less effortful, but a lesser reward. METHODS: Adult male C57BL/6J mice were administered either vehicle (n = 10) or CORT (n = 10) (~ 9.5 mg/kg/day) in their drinking water for 4 weeks, and then throughout all behavioral experiments (15 weeks total), and were tested in a Y-Maze barrier task and a fixed ratio concurrent (FR/chow) choice task. RESULTS: Chronic CORT reduced Y-maze HR arm choice when more effort was required to obtain the 4 food pellets (15-cm barrier in the high-reward (HR) arm, p < 0.001; 20-cm barrier in HR arm, p < 0.001) and shifted choice to the low reward (LR) arm where only 2 pellets were available. Chronic CORT also reduced lever pressing for food pellets in FR30/chow sessions of the concurrent choice task (p = 0.009), without impacting lab chow consumed. CONCLUSIONS: Chronic stress induces maladaptive shifts in effort-related choice behavior in the Y-maze barrier task in male mice. Furthermore, males subjected to chronic CORT administration show reduced lever pressing in FR30/chow sessions where lab chow is concurrently available. These data demonstrate that chronic corticosterone reduces motivation to work for and obtain a highly rewarding reinforcer when a lesser reinforcer is concurrently available.


Assuntos
Comportamento de Escolha/efeitos dos fármacos , Corticosterona/administração & dosagem , Aprendizagem em Labirinto/efeitos dos fármacos , Motivação/efeitos dos fármacos , Recompensa , Animais , Comportamento de Escolha/fisiologia , Esquema de Medicação , Comportamento Alimentar/efeitos dos fármacos , Comportamento Alimentar/fisiologia , Comportamento Alimentar/psicologia , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Motivação/fisiologia
12.
J Neurosci ; 40(18): 3576-3590, 2020 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-32234778

RESUMO

Theoretical models and experimental evidence have suggested that connections from the dentate gyrus (DG) to CA3 play important roles in representing orthogonal information (i.e., pattern separation) in the hippocampus. However, the effects of eliminating the DG on neural firing patterns in the CA3 have rarely been tested in a goal-directed memory task that requires both the DG and CA3. In this study, selective lesions in the DG were made using colchicine in male Long-Evans rats, and single units from the CA3 were recorded as the rats performed visual scene memory tasks. The original scenes used in training were altered during testing by blurring to varying degrees or by using visual masks, resulting in maximal recruitment of the DG-CA3 circuits. Compared with controls, the performance of rats with DG lesions was particularly impaired when blurred scenes were used in the task. In addition, the firing rate modulation associated with visual scenes in these rats was significantly reduced in the single units recorded from the CA3 when ambiguous scenes were presented, largely because DG-deprived CA3 cells did not show stepwise, categorical rate changes across varying degrees of scene ambiguity compared with controls. These findings suggest that the DG plays key roles not only during the acquisition of scene memories but also during retrieval when modified visual scenes are processed in conjunction with the CA3 by making the CA3 network respond orthogonally to ambiguous scenes.SIGNIFICANCE STATEMENT Despite the behavioral evidence supporting the role of the dentate gyrus in pattern separation in the hippocampus, the underlying neural mechanisms are largely unknown. By recording single units from the CA3 in DG-lesioned rats performing a visual scene memory task, we report that the scene-related modulation of neural firing was significantly reduced in the DG-lesion rats compared with controls, especially when the original scene stimuli were ambiguously altered. Our findings suggest that the dentate gyrus plays an essential role during memory retrieval and performs a critical computation to make categorical rate modulation occur in the CA3 between different scenes, especially when ambiguity is present in the environment.


Assuntos
Região CA3 Hipocampal/fisiologia , Giro Denteado/fisiologia , Memória/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa/métodos , Animais , Região CA3 Hipocampal/citologia , Giro Denteado/citologia , Masculino , Aprendizagem em Labirinto/fisiologia , Ratos , Ratos Long-Evans
13.
Cell ; 180(3): 552-567.e25, 2020 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-32004462

RESUMO

Cognitive faculties such as imagination, planning, and decision-making entail the ability to represent hypothetical experience. Crucially, animal behavior in natural settings implies that the brain can represent hypothetical future experience not only quickly but also constantly over time, as external events continually unfold. To determine how this is possible, we recorded neural activity in the hippocampus of rats navigating a maze with multiple spatial paths. We found neural activity encoding two possible future scenarios (two upcoming maze paths) in constant alternation at 8 Hz: one scenario per ∼125-ms cycle. Further, we found that the underlying dynamics of cycling (both inter- and intra-cycle dynamics) generalized across qualitatively different representational correlates (location and direction). Notably, cycling occurred across moving behaviors, including during running. These findings identify a general dynamic process capable of quickly and continually representing hypothetical experience, including that of multiple possible futures.


Assuntos
Comportamento Animal/fisiologia , Cognição/fisiologia , Tomada de Decisões/fisiologia , Hipocampo/fisiologia , Potenciais de Ação/fisiologia , Animais , Locomoção/fisiologia , Masculino , Aprendizagem em Labirinto/fisiologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Ratos , Ratos Long-Evans , Ritmo Teta/fisiologia
14.
J Neurosci ; 40(11): 2357-2370, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32029532

RESUMO

DNA damage and type I interferons (IFNs) contribute to inflammatory responses after traumatic brain injury (TBI). TBI-induced activation of microglia and peripherally-derived inflammatory macrophages may lead to tissue damage and neurological deficits. Here, we investigated the role of IFN-ß in secondary injury after TBI using a controlled cortical impact model in adult male IFN-ß-deficient (IFN-ß-/-) mice and assessed post-traumatic neuroinflammatory responses, neuropathology, and long-term functional recovery. TBI increased expression of DNA sensors cyclic GMP-AMP synthase and stimulator of interferon genes in wild-type (WT) mice. IFN-ß and other IFN-related and neuroinflammatory genes were also upregulated early and persistently after TBI. TBI increased expression of proinflammatory mediators in the cortex and hippocampus of WT mice, whereas levels were mitigated in IFN-ß-/- mice. Moreover, long-term microglia activation, motor, and cognitive function impairments were decreased in IFN-ß-/- TBI mice compared with their injured WT counterparts; improved neurological recovery was associated with reduced lesion volume and hippocampal neurodegeneration in IFN-ß-/- mice. Continuous central administration of a neutralizing antibody to the IFN-α/ß receptor (IFNAR) for 3 d, beginning 30 min post-injury, reversed early cognitive impairments in TBI mice and led to transient improvements in motor function. However, anti-IFNAR treatment did not improve long-term functional recovery or decrease TBI neuropathology at 28 d post-injury. In summary, TBI induces a robust neuroinflammatory response that is associated with increased expression of IFN-ß and other IFN-related genes. Inhibition of IFN-ß reduces post-traumatic neuroinflammation and neurodegeneration, resulting in improved neurological recovery. Thus, IFN-ß may be a potential therapeutic target for TBI.SIGNIFICANCE STATEMENT TBI frequently causes long-term neurological and psychiatric changes in head injury patients. TBI-induced secondary injury processes including persistent neuroinflammation evolve over time and can contribute to chronic neurological impairments. The present study demonstrates that TBI is followed by robust activation of type I IFN pathways, which have been implicated in microglial-associated neuroinflammation and chronic neurodegeneration. We examined the effects of genetic or pharmacological inhibition of IFN-ß, a key component of type I IFN mechanisms to address its role in TBI pathophysiology. Inhibition of IFN-ß signaling resulted in reduced neuroinflammation, attenuated neurobehavioral deficits, and limited tissue loss long after TBI. These preclinical findings suggest that IFN-ß may be a potential therapeutic target for TBI.


Assuntos
Dano Encefálico Crônico/fisiopatologia , Lesões Encefálicas Traumáticas/fisiopatologia , Interferon beta/fisiologia , Degeneração Neural/etiologia , Animais , Dano Encefálico Crônico/etiologia , Lesões Encefálicas Traumáticas/complicações , Córtex Cerebral/metabolismo , Comportamento Exploratório/fisiologia , Regulação da Expressão Gênica , Hipocampo/metabolismo , Inflamação , Interferon beta/biossíntese , Interferon beta/deficiência , Interferon beta/genética , Masculino , Aprendizagem em Labirinto/fisiologia , Transtornos da Memória/etiologia , Transtornos da Memória/fisiopatologia , Camundongos , Camundongos Endogâmicos C57BL , Microglia/fisiologia , Transtornos dos Movimentos/etiologia , Transtornos dos Movimentos/fisiopatologia , Distribuição Aleatória , Receptor de Interferon alfa e beta/imunologia , Transdução de Sinais , Regulação para Cima
15.
Psychopharmacology (Berl) ; 237(5): 1331-1342, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32034448

RESUMO

RATIONALE: Searches for antidotes to cocaine, and for cognition enhancers potentially applicable to Alzheimer's disease, have revealed a novel regulatory site on nicotinic acetylcholine receptors. In the presence of an agonist, inhibitors binding to this site changed the ion channel equilibrium from the open-channel form towards the closed form. Other, related, molecules could bind to the site without changing the equilibrium. These latter compounds were predicted to displace the inhibitors without affecting receptor function per se. These compounds alleviated the inhibition. One of them is ecgonine methyl ester (EME), which is generally described as inactive, but this work suggested a beneficial effect on cognition. OBJECTIVE: This in vivo study tested for cognitive enhancement by EME in scopolamine-impaired, and aged, rats. METHODS: Memory was the primary endpoint, but thigmotaxis became an important secondary endpoint in the light of observations made during the study. Impaired cognition was pharmacologically induced by scopolamine in young rats, and spontaneously present in aged rats. Learning ability before and after administration of EME was tested in Morris water maze protocols. Concentrations of EME in the brain and plasma were analyzed by gas chromatography-mass spectrometry. RESULTS: A single dose of EME reversed scopolamine impairment, indicating involvement of acetylcholine receptors. Longer-term treatment improved cognition in aged rats, with enhanced rates of learning in the absence of an exogenous cognition-impairing compound. Impairment returned with a new challenge; the improvement could be re-established with continued dosing. EME also reversed thigmotaxis seen in aged rats; thigmotaxis is believed to indicate anxiety. The concentrations of EME in the brain proved adequate drug exposure. CONCLUSIONS: Since other investigators have shown cognition impairment caused by cocaine in aged rats, this work shows that cocaine and EME have opposite effects in Morris water maze models. EME might induce cognitive enhancement and relief of anxiety in cocaine-impaired humans, and in other cognitive disorders.


Assuntos
Envelhecimento/efeitos dos fármacos , Antagonistas Colinérgicos/toxicidade , Cocaína/análogos & derivados , Cognição/efeitos dos fármacos , Entorpecentes/farmacologia , Escopolamina/toxicidade , Envelhecimento/fisiologia , Envelhecimento/psicologia , Animais , Cocaína/farmacologia , Cocaína/uso terapêutico , Cognição/fisiologia , Transtornos Cognitivos/induzido quimicamente , Transtornos Cognitivos/tratamento farmacológico , Transtornos Cognitivos/psicologia , Inibidores da Captação de Dopamina/farmacologia , Inibidores da Captação de Dopamina/uso terapêutico , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Memória/efeitos dos fármacos , Memória/fisiologia , Entorpecentes/uso terapêutico , Ratos , Ratos Sprague-Dawley
16.
Life Sci ; 245: 117386, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32006528

RESUMO

AIMS: Steroid receptor coactivator-1 (SRC-1) is a key coactivator for the efficient transcriptional activity of steroids in the regulation of hippocampal functions. However, the effect of SRC-1 on hippocampal memory processes remains unknown. Our aim was to investigate the roles of hippocampal SRC-1 in the consolidation and reconsolidation of contextual fear memory in mice. MAIN METHODS: Contextual fear conditioning paradigm was constructed in adult male C57BL/6 mice to examine the fear learning and memory processes. Adeno-associated virus (AAV) vector-mediated RNA interference (RNAi) was infused into hippocampus to block hippocampal SRC-1 level. Immunofluorescent staining was used to detect the efficiency of transfection. High plus maze and open field test were used to determine anxiety and locomotor activity. Western blot analyses were used to detect the expression of SRC-1 and synaptic proteins in the hippocampus. KEY FINDINGS: We first showed that the expression of SRC-1 was regulated by fear conditioning training in a time-dependent manner, and knockdown of SRC-1 impaired contextual fear memory consolidation without affecting innate anxiety or locomotor activity. In addition, hippocampal SRC-1 was also regulated by the retrieval of contextual fear memory, and downregulation of SRC-1 disrupted fear memory reconsolidation. Moreover, knockdown of SRC-1 reversed the increased GluR1 and PSD-95 levels induced by contextual fear memory retrieval. SIGNIFICANCE: Our data indicate that hippocampal SRC-1 is required for the consolidation and reconsolidation of contextual fear memory, and SRC-1 may be a potential therapeutic target for mental disorders that are involved in hippocampal memory dysfunction.


Assuntos
Medo/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Memória/efeitos dos fármacos , Coativador 1 de Receptor Nuclear/antagonistas & inibidores , Animais , Western Blotting , Condicionamento Clássico/efeitos dos fármacos , Condicionamento Clássico/fisiologia , Medo/fisiologia , Medo/psicologia , Imunofluorescência , Hipocampo/fisiologia , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Coativador 1 de Receptor Nuclear/fisiologia
17.
Int J Mol Sci ; 21(4)2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32098080

RESUMO

A T-maze test is an experimental approach that is used in congenital research. However, the food reward-based protocol for the T-maze test in fish has low efficiency and a long training period. The aim of this study is to facilitate the T-maze conditions by using a combination of the principles of passive avoidance and a spatial memory test. In our modified T-maze settings, electric shock punishment (1-2 V, 0.3-0.5 mA) is given at the left arm, with a green cue at the right arm. Also, the depth of both arms of the T-maze was increased. The parameters measured in our T-maze design were latency, freezing time, and time spent in different areas of the T-maze. We validated the utility of our modified T-maze protocol by showing the consistent finding of memory impairment in ZnCl2-treated fish, which has been previously detected with the passive avoidance test. In addition, we also tested the spatial memory performance of leptin a (lepa) mutants which displayed an obesity phenotype. The results showed that although the learning and memory performance for lepa KO fish were similar to control fish, they displayed a higher freezing behavior during the training phase. In conclusion, we have established a modified T-maze protocol that can be used to evaluate the anxiety, learning, and memory capacity of adult zebrafish within three days, for the first time.


Assuntos
Aprendizagem em Labirinto/fisiologia , Memória/fisiologia , Peixe-Zebra/fisiologia , Animais
18.
Psychopharmacology (Berl) ; 237(4): 1233-1243, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31953648

RESUMO

RATIONALE AND OBJECTIVE: Vortioxetine has been reported to exhibit a variety of neurobiological functions and neuroprotective effects. In the present study, we aimed to investigate the effects of vortioxetine on cognitive performance in a transgenic mouse model of Alzheimer's disease (AD). METHODS: We administered vortioxetine (10 mg/kg, i.p., every day, for approximately 6 weeks), which acts on multiple 5-serotonin (5-HT) receptors, to 3.5-month-old 5×FAD mice. Subsequently, we used the open field (OF) test to detect anxiety-like behavior in the mice. The novel object recognition (NOR) test and Morris water maze (MWM) were used to assess the cognitive states of the 5×FAD mice. We also measured the levels of insoluble amyloid plaques and soluble ß-amyloid (Aß) plaques. Finally, we explored the expression levels of postsynaptic density protein 95 (PSD95), synaptophysin (SYP), and synaptotagmin-1 (SYT1) in the hippocampus of the mice. RESULTS: The administration of vortioxetine effectively reversed the reduction in anxiety-type behaviors in 5×FAD mice and improved the impairment in recognition memory and spatial reference memory. However, we did not find that vortioxetine decreased or delayed the formation of amyloid plaques or Aß. Interestingly, we found a significant increase in the expression levels of PSD95, SYP, and SYT1 in the 5×FAD mice after vortioxetine treatment compared with the control group. CONCLUSION: These results demonstrate that vortioxetine may improve cognitive impairment in 5×FAD mice. The role in cognitive improvement may be related to the beneficial effects of vortioxetine on synaptic function.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Disfunção Cognitiva/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Sinapses/efeitos dos fármacos , Vortioxetina/uso terapêutico , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Animais , Disfunção Cognitiva/genética , Disfunção Cognitiva/patologia , Flavina-Adenina Dinucleotídeo/genética , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Humanos , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Transgênicos , Fármacos Neuroprotetores/farmacologia , Placa Amiloide/tratamento farmacológico , Placa Amiloide/genética , Placa Amiloide/patologia , Sinapses/patologia , Vortioxetina/farmacologia
19.
Psychopharmacology (Berl) ; 237(5): 1281-1290, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31965254

RESUMO

RATIONALE: Some mood disorders, such as major depressive disorder, are more prevalent in women than in men. However, historically preclinical studies in rodents have a lower inclusion rate of females than males, possibly due to the fact that behavior can be affected by the estrous cycle. Several studies have demonstrated that chronic antidepressant treatment can decrease anxiety-associated behaviors and increase adult hippocampal neurogenesis in male rodents. OBJECTIVE: Very few studies have looked at the effects of antidepressants on behavior and neurogenesis across the estrous cycle in naturally cycling female rodents. METHODS: Here, we analyze the effects of chronic treatment with the selective serotonin reuptake inhibitor (SSRI) fluoxetine (Prozac) on behavior and adult hippocampal neurogenesis in naturally cycling C57BL/6J females across all four phases of the estrous cycle. RESULTS: In naturally cycling C57BL/6J females, fluoxetine decreases negative valence behaviors associated with anxiety in the elevated plus maze and novelty-suppressed feeding task, reduces immobility time in forced swim test, and increases adult hippocampal neurogenesis. Interestingly, the effects of fluoxetine on several negative valence behavior and adult hippocampal neurogenesis measures were mainly found within the estrus and diestrus phases of the estrous cycle. CONCLUSIONS: Taken together, these data are the first to illustrate the effects of fluoxetine on behavior and adult hippocampal neurogenesis across all four phases of the murine estrous cycle.


Assuntos
Ciclo Estral/efeitos dos fármacos , Fluoxetina/farmacologia , Hipocampo/efeitos dos fármacos , Aprendizagem em Labirinto/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Inibidores de Captação de Serotonina/farmacologia , Animais , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Depressão/tratamento farmacológico , Depressão/psicologia , Ciclo Estral/fisiologia , Feminino , Fluoxetina/uso terapêutico , Hipocampo/citologia , Hipocampo/fisiologia , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Neurogênese/fisiologia , Inibidores de Captação de Serotonina/uso terapêutico
20.
Psychopharmacology (Berl) ; 237(5): 1305-1315, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31984446

RESUMO

RATIONALE: To demonstrate that repeated episodes of binge drinking during the adolescent period can lead to long-term deficits in motor function and memory in adulthood, and increase proteins in the brain involved with inflammation and apoptotic cell death. METHODS: Groups of early adolescent (PND 26) and periadolescent (PND 34) Sprague-Dawley rats were exposed to either ethanol or plain air through a vapor chamber apparatus for five consecutive days (2 h per day), achieving a blood ethanol concentration equivalent to 6-8 drinks in the treatment group. Subjects then underwent a series of behavioral tests designed to assess memory, anxiety regulation, and motor function. Brains were collected on PND 94 for subsequent western blot analysis. RESULTS: Behavioral testing using the rota-rod, cage-hang, novel object recognition, light-dark box, and elevated plus maze apparatuses showed significant differences between groups; several of which persisted for up to 60 days after treatment. Western blot testing indicated elevated levels of caspase-3/cleaved caspase-3, NF-kB, and PKC/pPKC proteins in the cerebella of ethanol-treated animals. CONCLUSIONS: Differences on anxiety tests indicate a possible failure of behavioral inhibition in the treatment group leading to riskier behavior. Binge drinking also impairs motor coordination and object memory, which involve the cerebellar and hippocampal brain regions, respectively. These experiments indicate the potential dangers of binge drinking while the brain is still developing and indicate the need for future studies in this area.


Assuntos
Apoptose/fisiologia , Bebedeira/metabolismo , Bebedeira/psicologia , Cerebelo/metabolismo , Etanol/administração & dosagem , Mediadores da Inflamação/metabolismo , Administração por Inalação , Fatores Etários , Animais , Apoptose/efeitos dos fármacos , Cerebelo/efeitos dos fármacos , Etanol/toxicidade , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Ratos , Ratos Sprague-Dawley , Reflexo de Sobressalto/efeitos dos fármacos , Reflexo de Sobressalto/fisiologia
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