RESUMEN
Senescent cells contribute to tissue aging and underlie the pathology of chronic diseases. The benefits of eliminating senescent cells have been demonstrated in several disease models, and the efficacy of senolytic drugs is currently being tested in humans. Exercise training has been shown to reduce cellular senescence in several tissues; however, the mechanisms responsible remain unclear. We found that myocyte-derived factors significantly extended the replicative lifespan of fibroblasts, suggesting that myokines mediate the anti-senescence effects of exercise. A number of proteins within myocyte-derived factors were identified by mass spectrometry. Among these, pigment epithelium-derived factor (PEDF) exerted inhibitory effects on cellular senescence. Eight weeks of voluntary running increased Pedf levels in skeletal muscles and suppressed senescence markers in the lungs. The administration of PEDF reduced senescence markers in multiple tissues and attenuated the decline in respiratory function in the pulmonary emphysema mouse model. We also showed that blood levels of PEDF inversely correlated with the severity of COPD in patients. Collectively, these results strongly suggest that PEDF contributes to the beneficial effects of exercise, potentially suppressing cellular senescence and its associated pathologies.
Asunto(s)
Senescencia Celular , Proteínas del Ojo , Pulmón , Factores de Crecimiento Nervioso , Condicionamiento Físico Animal , Serpinas , Serpinas/metabolismo , Factores de Crecimiento Nervioso/metabolismo , Animales , Proteínas del Ojo/metabolismo , Ratones , Pulmón/metabolismo , Pulmón/patología , Humanos , Condicionamiento Físico Animal/fisiología , Masculino , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/patología , Fibroblastos/metabolismo , Modelos Animales de Enfermedad , Ratones Endogámicos C57BL , Femenino , Músculo Esquelético/metabolismo , Enfisema Pulmonar/metabolismo , Enfisema Pulmonar/patologíaRESUMEN
OBJECTIVES: Many patients with Alzheimer's disease (AD) experience behavioral and psychological symptoms of dementia (BPSD), which significantly affect their quality of life. It is known that 5-Hydroxytryptamine (5-HT) plays a crucial role in the development of BPSD. While the relationship between tooth loss and AD symptoms has been acknowledged, the aspect of aggression has not been focused on until now. Despite the established importance of 5-HT in BPSD, how tooth loss is related to the exacerbation of AD symptoms, especially in terms of aggression, remains largely unexplored. Although nutritional status is known to influence the progression of dementia, the specific effect of tooth loss on peripheral symptoms, notably aggression, is not well understood. METHODS: In our study, we conducted maxillary molar extractions in aged C57BL/6J and AppNL-G-F mice and observed their condition over a 3-month period. During this time, we documented significant behavioral and genetic differences between mice in the control groups and mice that underwent tooth extraction. Notably, mice that underwent tooth extraction exhibited a considerable decline in cognitive function and increased in aggression 3 months after tooth extraction compared with the control groups (C57BL/6J and AppNL-G-Fmice). RESULTS: Our findings suggest that molar loss may lead to reduced 5-HT levels in the hippocampus, possibly mediated by the trigeminal nerve, contributing to the development of aggression and BPSD in AD. CONCLUSION: This study sheds light on the intricate relationships between oral health, 5-HT, and AD symptoms, offering valuable insights into potential therapeutic avenues for managing BPSD in patients with dementia.
Asunto(s)
Agresión , Ratones Endogámicos C57BL , Pérdida de Diente , Animales , Ratones , Pérdida de Diente/genética , Pérdida de Diente/psicología , Agresión/psicología , Agresión/fisiología , Conducta Animal , Modelos Animales de Enfermedad , Demencia/genética , Demencia/psicología , Ratones Transgénicos , Masculino , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/psicología , Enfermedad de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismoRESUMEN
The exact sites of premature hair graying and whether tooth loss causes this condition remain unknown. In this study, we aimed to explore the effect of reduced mastication on premature hair graying. Maxillary first molars were extracted from young mice, and the mice were observed for 3 months, along with non-extraction control group mice. After 3 months, gray hair emerged in the interbrow region of mice in the tooth extraction group but not in the control group. The expression of tyrosinase-related protein-2 (TRP-2) mRNA was lower in the interbrow tissues of young mice without maxillary molars than in those with maxillary molars. Tooth loss leads to interbrow gray hair growth, possibly because of weakened trigeminal nerve input, suggesting that reduced mastication causes premature graying. Thus, prompt prosthetic treatment after molar loss is highly recommended.
Asunto(s)
Diente Molar , Animales , Ratones , Diente Molar/metabolismo , Color del Cabello/genética , Maxilar/metabolismo , Maxilar/crecimiento & desarrollo , Pérdida de Diente , Masculino , Ratones Endogámicos C57BLRESUMEN
In the original publication [...].
RESUMEN
Sleep deprivation (SD) causes several adverse functional outcomes, and understanding the associated processes can improve quality of life. Although the effects of SD on neuronal activity in several brain regions have been identified, a comprehensive evaluation of the whole brain is still lacking. Hence, we performed SD using two different methods, gentle handling and a dedicated chamber, in targeted recombination in active populations 2 (TRAP2) mice crossed with Rosa-ZsGreen reporter mice and visualized cellular activity in the whole brain. Using the semi-automated post-imaging analysis tool Slice Histology Alignment, Registration, and Cell Quantification (SHARCQ), the number of activated cells was quantified. From the analysis of 14 brain regions, cellular activity was significantly increased in the olfactory areas and decreased in the medulla by the two SD methods. From the analysis of the further subdivided 348 regions, cellular activity was significantly increased in the vascular organ of the lamina terminalis, lateral hypothalamic area, parabigeminal nucleus, ventral tegmental area, and magnocellular reticular nucleus, and decreased in the anterior part of the basolateral amygdalar nucleus, nucleus accumbens, septohippocampal nucleus, reticular nucleus of the thalamus, preoptic part of the periventricular hypothalamic nucleus, ventromedial preoptic nucleus, rostral linear nucleus raphe, facial motor nucleus, vestibular nuclei, and some fiber tracts (oculomotor nerve, genu of corpus callosum, and rubrospinal tract) by the two SD methods. Two subdivided regions of the striatum (caudoputamen and other striatum), epithalamus, vascular organ of the lamina terminalis, anteroventral preoptic nucleus, superior colliculus optic layer, medial terminal nucleus of the accessory optic tract, pontine gray, and fiber tracts (medial lemniscus, columns of the fornix, brachium of the inferior colliculus, and mammillary peduncle) were differentially affected by the two SD methods. Most brain regions detected from these analyses have been reported to be involved in regulating sleep/wake regulatory circuits. Moreover, the results from the connectivity analysis indicated that the connectivity of cellular activity among brain regions was altered by SD. Together, such a comprehensive analysis of the whole brain is useful for understanding the mechanisms by which SD and/or sleep disruption affects brain function.
RESUMEN
Tooth loss and decreased masticatory function reportedly affect cognitive function; tooth loss allegedly induces astrogliosis and aging of astrocytes in the hippocampus and hypothalamus, which is a response specific to the central nervous system owing to homeostasis in different brain regions. Capsaicin, a component of red peppers, has positive effects on brain disorders in mice. Decreased expression of transient receptor potential vanilloid 1, a receptor of capsaicin, is associated with the development of dementia. In this study, we investigated the effect of capsaicin administration in aged mice (C57BL/6N mice) with reduced masticatory function owing to the extraction of maxillary molars to investigate preventive/therapeutic methods for cognitive decline attributed to age-related masticatory function loss. The results demonstrated that mice with impaired masticatory function showed decreased motor and cognitive function at the behavioral level. At the genetic level, neuroinflammation, microglial activity, and astrogliosis, such as increased glial fibrillary acidic protein levels, were observed in the mouse brain. The mice with extracted molars fed on a diet containing capsaicin for 3 months demonstrated improved behavioral levels and astrogliosis, which suggest that capsaicin is useful in maintaining brain function in cases of poor oral function and prosthetic difficulties.
Asunto(s)
Capsaicina , Pérdida de Diente , Ratones , Animales , Capsaicina/farmacología , Gliosis/tratamiento farmacológico , Pérdida de Diente/tratamiento farmacológico , Ratones Endogámicos C57BL , Encéfalo/metabolismo , Canales Catiónicos TRPV/metabolismoRESUMEN
The relationship between caloric and nutrient intake and overall health has been extensively studied. However, little research has focused on the impact of the hardness of staple foods on health. In this study, we investigated the effects of a soft diet on brain function and behavior in mice from an early age. Mice fed a soft diet for six months exhibited increased body weight and total cholesterol levels, along with impaired cognitive and motor function, heightened nocturnal activity, and increased aggression. Interestingly, when these mice were switched back to a solid diet for three months, their weight gain ceased, total cholesterol levels stabilized, cognitive function improved, and aggression decreased, while their nocturnal activity remained high. These findings suggest that long-term consumption of a soft diet during early development can influence various behaviors associated with anxiety and mood regulation, including weight gain, cognitive decline, impaired motor coordination, increased nocturnal activity, and heightened aggression. Therefore, the hardness of food can impact brain function, mental well-being, and motor skills during the developmental stage. Early consumption of hard foods may be crucial for promoting and maintaining healthy brain function.
Asunto(s)
Dieta , Ingestión de Energía , Ratones , Animales , Aumento de Peso , Encéfalo , Colesterol/farmacologíaRESUMEN
Old animals display significant alterations in sleep-wake patterns such as increases in sleep fragmentation and sleep propensity. Here, we demonstrated that PR-domain containing protein 13 (Prdm13)+ neurons in the dorsomedial hypothalamus (DMH) are activated during sleep deprivation (SD) in young mice but not in old mice. Chemogenetic inhibition of Prdm13+ neurons in the DMH in young mice promotes increase in sleep attempts during SD, suggesting its involvement in sleep control. Furthermore, DMH-specific Prdm13-knockout (DMH-Prdm13-KO) mice recapitulated age-associated sleep alterations such as sleep fragmentation and increased sleep attempts during SD. These phenotypes were further exacerbated during aging, with increased adiposity and decreased physical activity, resulting in shortened lifespan. Dietary restriction (DR), a well-known anti-aging intervention in diverse organisms, ameliorated age-associated sleep fragmentation and increased sleep attempts during SD, whereas these effects of DR were abrogated in DMH-Prdm13-KO mice. Moreover, overexpression of Prdm13 in the DMH ameliorated increased sleep attempts during SD in old mice. Therefore, maintaining Prdm13 signaling in the DMH might play an important role to control sleep-wake patterns during aging.
Asunto(s)
Hipotálamo , Privación de Sueño , Ratones , Animales , Hipotálamo/metabolismo , Privación de Sueño/metabolismo , Obesidad/metabolismo , Sueño , Dieta , N-Metiltransferasa de Histona-Lisina/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Age-related tooth loss impedes mastication. Epidemiological and physiological studies have reported that poor oral hygiene and occlusion are associated with cognitive decline. In the present study, we analyzed the mechanism by which decreased occlusal support following bilateral extraction of the maxillary first molars affects cognitive functions in young and aged mice and examined the expression of brain-function-related genes in the hippocampus and hypothalamus. We observed decreased working memory, enhanced restlessness, and increased nocturnal activity in aged mice with molar extraction compared with that in mice with intact molars. Furthermore, in the hypothalamus and hippocampus of molar-extracted aged mice, the transcript-level expression of Bdnf, Rbfox3, and Fos decreased, while that of Cdkn2a and Aif1 increased. Thus, decreased occlusal support after maxillary first molar extraction may affect cognitive function and activity in mice by influencing aging, neural activity, and neuroinflammation in the hippocampus and hypothalamus.
Asunto(s)
Gliosis , Pérdida de Diente , Animales , Gliosis/metabolismo , Hipocampo/metabolismo , Hipotálamo , Ratones , Diente Molar , Pérdida de Diente/complicacionesRESUMEN
Brain damage such as stroke is a devastating neurological condition that may severely compromise patient quality of life. No effective medication-mediated intervention to accelerate rehabilitation has been established. We found that a small compound, edonerpic maleate, facilitated experience-driven synaptic glutamate AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic-acid) receptor delivery and resulted in the acceleration of motor function recovery after motor cortex cryoinjury in mice in a training-dependent manner through cortical reorganization. Edonerpic bound to collapsin-response-mediator-protein 2 (CRMP2) and failed to augment recovery in CRMP2-deficient mice. Edonerpic maleate enhanced motor function recovery from internal capsule hemorrhage in nonhuman primates. Thus, edonerpic maleate, a neural plasticity enhancer, could be a clinically potent small compound with which to accelerate rehabilitation after brain damage.
Asunto(s)
Lesiones Encefálicas/tratamiento farmacológico , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Maleatos/metabolismo , Maleatos/farmacología , Corteza Motora/efectos de los fármacos , Proteínas del Tejido Nervioso/metabolismo , Neuroprotección , Recuperación de la Función/efectos de los fármacos , Tiofenos/metabolismo , Tiofenos/farmacología , Animales , Masculino , Maleatos/uso terapéutico , Ratones , Ratones Noqueados , Ratones Mutantes , Corteza Motora/lesiones , Corteza Motora/fisiopatología , Plasticidad Neuronal/efectos de los fármacos , Calidad de Vida , Receptores AMPA/metabolismo , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/tratamiento farmacológico , Tiofenos/uso terapéuticoRESUMEN
Exposure to a stressful environment early in life can cause psychiatric disorders by disrupting circuit formation. Actin plays central roles in regulating neuronal structure and protein trafficking. We have recently reported that neonatal isolation inactivated ADF/cofilin, the actin depolymerizing factor, resulted in a reduced actin dynamics at spines and an attenuation of synaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor delivery in the juvenile rat medial prefrontal cortex (mPFC), leading to altered social behaviours. Here, we investigated the impact of neonatal social isolation in the developing rat barrel cortex. Similar to the mPFC study, we detected an increase in stable actin fraction in spines and this resulted in a decreased synaptic AMPA receptor delivery. Thus, we conclude that early life social isolation affects multiple cortical areas with common molecular changes.
Asunto(s)
Actinas/fisiología , Destrina/fisiología , Plasticidad Neuronal/fisiología , Aislamiento Social , Animales , Animales Recién Nacidos/crecimiento & desarrollo , Femenino , Masculino , Proteínas de Microfilamentos/fisiología , Neurogénesis/fisiología , Corteza Prefrontal/crecimiento & desarrollo , Corteza Prefrontal/metabolismo , Transporte de Proteínas , Ratas Sprague-Dawley , Receptores AMPA/metabolismoRESUMEN
The synaptic delivery of neurotransmitter receptors, such as GluA1 AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors, mediates important processes in cognitive function, including memory acquisition and retention. Understanding the roles of these receptors has been hampered by the lack of a method to inactivate them in vivo with high spatiotemporal precision. We developed a technique to inactivate synaptic GluA1 AMPA receptors in vivo using chromophore-assisted light inactivation (CALI). We raised a monoclonal antibody specific for the extracellular domain of GluA1 that induced effective CALI when conjugated with a photosensitizer (eosin). Mice that had been injected in the CA1 hippocampal region with the antibody conjugate underwent a fear memory task. Exposing the hippocampus to green light using an implanted cannula erased acquired fear memory in the animals by inactivation of synaptic GluA1. Our optical technique for inactivating synaptic proteins will enable elucidation of their physiological roles in cognition.
Asunto(s)
Extinción Psicológica/fisiología , Miedo/fisiología , Memoria/fisiología , Estimulación Luminosa/métodos , Receptores AMPA/antagonistas & inhibidores , Sinapsis/fisiología , Animales , Extinción Psicológica/efectos de la radiación , Miedo/efectos de la radiación , Hipocampo/fisiología , Hipocampo/efectos de la radiación , Luz , Masculino , Memoria/efectos de la radiación , Ratones , Ratones Endogámicos ICR , Inhibición Neural/fisiología , Inhibición Neural/efectos de la radiación , Receptores AMPA/metabolismo , Receptores AMPA/efectos de la radiación , Sinapsis/efectos de la radiaciónRESUMEN
Patient-specific induced pluripotent stem cells (iPSCs) facilitate understanding of the etiology of diseases, discovery of new drugs and development of novel therapeutic interventions. A frequently used starting source of cells for generating iPSCs has been dermal fibroblasts (DFs) isolated from skin biopsies. However, there are also numerous repositories containing lymphoblastoid B-cell lines (LCLs) generated from a variety of patients. To date, this rich bioresource of LCLs has been underused for generating iPSCs, and its use would greatly expand the range of targeted diseases that could be studied by using patient-specific iPSCs. However, it remains unclear whether patient's LCL-derived iPSCs (LiPSCs) can function as a disease model. Therefore, we generated Parkinson's disease patient-specific LiPSCs and evaluated their utility as tools for modeling neurological diseases. We established iPSCs from two LCL clones, which were derived from a healthy donor and a patient carrying PARK2 mutations, by using existing non-integrating episomal protocols. Whole genome sequencing (WGS) and comparative genomic hybridization (CGH) analyses showed that the appearance of somatic variations in the genomes of the iPSCs did not vary substantially according to the original cell types (LCLs, T-cells and fibroblasts). Furthermore, LiPSCs could be differentiated into functional neurons by using the direct neurosphere conversion method (dNS method), and they showed several Parkinson's disease phenotypes that were similar to those of DF-iPSCs. These data indicate that the global LCL repositories can be used as a resource for generating iPSCs and disease models. Thus, LCLs are the powerful tools for generating iPSCs and modeling neurological diseases.
Asunto(s)
Reprogramación Celular , Células Madre Pluripotentes Inducidas/citología , Linfocitos/citología , Modelos Biológicos , Enfermedades del Sistema Nervioso/patología , Secuencia de Bases , Diferenciación Celular , Línea Celular Transformada , Dermis/citología , Fibroblastos/citología , Herpesvirus Humano 4/fisiología , Humanos , Mitocondrias/metabolismo , Mutación/genética , Neuronas/citología , Enfermedad de Parkinson/patología , Fenotipo , Esferoides Celulares/citología , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Social separation early in life can lead to the development of impaired interpersonal relationships and profound social disorders. However, the underlying cellular and molecular mechanisms involved are largely unknown. Here, we found that isolation of neonatal rats induced glucocorticoid-dependent social dominance over nonisolated control rats in juveniles from the same litter. Furthermore, neonatal isolation inactivated the actin-depolymerizing factor (ADF)/cofilin in the juvenile medial prefrontal cortex (mPFC). Isolation-induced inactivation of ADF/cofilin increased stable actin fractions at dendritic spines in the juvenile mPFC, decreasing glutamate synaptic AMPA receptors. Expression of constitutively active ADF/cofilin in the mPFC rescued the effect of isolation on social dominance. Thus, neonatal isolation affects spines in the mPFC by reducing actin dynamics, leading to altered social behavior later in life.
RESUMEN
Modeling of neurological diseases using induced pluripotent stem cells (iPSCs) derived from the somatic cells of patients has provided a means of elucidating pathogenic mechanisms and performing drug screening. T cells are an ideal source of patient-specific iPSCs because they can be easily obtained from samples. Recent studies indicated that iPSCs retain an epigenetic memory relating to their cell of origin that restricts their differentiation potential. The classical method of differentiation via embryoid body formation was not suitable for T cell-derived iPSCs (TiPSCs). We developed a neurosphere-based robust differentiation protocol, which enabled TiPSCs to differentiate into functional neurons, despite differences in global gene expression between TiPSCs and adult human dermal fibroblast-derived iPSCs. Furthermore, neurons derived from TiPSCs generated from a juvenile patient with Parkinson's disease exhibited several Parkinson's disease phenotypes. Therefore, we conclude that TiPSCs are a useful tool for modeling neurological diseases.
Asunto(s)
Células Madre Pluripotentes Inducidas/citología , Neurogénesis , Neuronas/citología , Cultivo Primario de Células/métodos , Linfocitos T/citología , Células Cultivadas , Fibroblastos/citología , HumanosRESUMEN
Experience-dependent plasticity is limited in the adult brain, and its molecular and cellular mechanisms are poorly understood. Removal of the myelin-inhibiting signaling protein, Nogo receptor (NgR1), restores adult neural plasticity. Here we found that, in NgR1-deficient mice, whisker experience-driven synaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) insertion in the barrel cortex, which is normally complete by 2 weeks after birth, lasts into adulthood. In vivo live imaging by two-photon microscopy revealed more AMPAR on the surface of spines in the adult barrel cortex of NgR1-deficient than on those of wild-type (WT) mice. Furthermore, we observed that whisker stimulation produced new spines in the adult barrel cortex of mutant but not WT mice, and that the newly synthesized spines contained surface AMPAR. These results suggest that Nogo signaling limits plasticity by restricting synaptic AMPAR delivery in coordination with anatomical plasticity.
Asunto(s)
Corteza Cerebral/fisiología , Espinas Dendríticas/fisiología , Proteínas de la Mielina/metabolismo , Plasticidad Neuronal/fisiología , Receptores AMPA/metabolismo , Sinapsis/fisiología , Animales , Corteza Cerebral/metabolismo , Ratones Transgénicos , Transducción de Señal/fisiología , Vibrisas/fisiologíaRESUMEN
Cognitive function can be affected by the estrous cycle. However, the effect of the estrous cycle on synaptic functions is poorly understood. Here we show that in female rats, inhibitory-avoidance (IA) task (hippocampus-dependent contextual fear-learning task) drives GluA2-lacking Ca2+-permeable AMPA receptors (CP-AMPARs) into the hippocampal CA3-CA1 synapses during all periods of the estrous cycle except the proestrous period, when estrogen levels are high. In addition, IA task failed to drive CP-AMPARs into the CA3-CA1 synapses of ovariectomized rats only when estrogen was present. Thus, changes in the stoichiometry of AMPA receptors during learning depend on estrogen levels. Furthermore, the induction of long-term potentiation (LTP) after IA task was prevented during the proestrous period, while intact LTP is still expressed after IA task during other period of the estrous cycle. Consistent with this finding, rats conditioned by IA training failed to acquire hippocampus-dependent Y-maze task during the proestrous period. On the other hand, during other estrous period, rats were able to learn Y-maze task after IA conditioning. These results suggest that high estrogen levels prevent the IA learning-induced delivery of CP-AMPARs into hippocampal CA3-CA1 synapses and limit synaptic plasticity after IA task, thus preventing the acquisition of additional learning.
Asunto(s)
Ciclo Estral , Hipocampo/metabolismo , Receptores AMPA/metabolismo , Sinapsis/metabolismo , Animales , Reacción de Prevención/efectos de los fármacos , Región CA3 Hipocampal/efectos de los fármacos , Región CA3 Hipocampal/metabolismo , Calcio/metabolismo , Permeabilidad de la Membrana Celular/efectos de los fármacos , Espinas Dendríticas/efectos de los fármacos , Espinas Dendríticas/metabolismo , Estrógenos/farmacología , Ciclo Estral/efectos de los fármacos , Femenino , Hipocampo/efectos de los fármacos , Potenciación a Largo Plazo/efectos de los fármacos , Inhibición Neural/efectos de los fármacos , Ovariectomía , Células Piramidales/efectos de los fármacos , Células Piramidales/metabolismo , Ratas Wistar , Sinapsis/efectos de los fármacos , Análisis y Desempeño de TareasRESUMEN
Stressful events during early childhood can have a profound lifelong influence on emotional and cognitive behaviors. However, the mechanisms by which stress affects neonatal brain circuit formation are poorly understood. Here, we show that neonatal social isolation disrupts molecular, cellular, and circuit developmental processes, leading to behavioral dysfunction. Neonatal isolation prevented long-term potentiation and experience-dependent synaptic trafficking of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors normally occurring during circuit formation in the rodent barrel cortex. This inhibition of AMPA receptor trafficking was mediated by an increase of the stress glucocorticoid hormone and was associated with reduced calcium/calmodulin-dependent protein kinase type II (CaMKII) signaling, resulting in attenuated whisker sensitivity at the cortex. These effects led to defects in whisker-dependent behavior in juvenile animals. These results indicate that neonatal social isolation alters neuronal plasticity mechanisms and perturbs the initial establishment of a normal cortical circuit, which potentially explains the long-lasting behavioral effects of neonatal stress.
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Conducta Animal , Aislamiento Social , Corteza Somatosensorial/fisiología , Estrés Psicológico , Animales , Animales Recién Nacidos , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Corticosterona/sangre , Femenino , Glucocorticoides/sangre , Potenciación a Largo Plazo , Masculino , Plasticidad Neuronal , Norepinefrina/metabolismo , Fosforilación , Procesamiento Proteico-Postraduccional , Transporte de Proteínas , Ratas , Ratas Sprague-Dawley , Receptores AMPA/metabolismo , Privación Sensorial , Corteza Somatosensorial/metabolismo , Transmisión Sináptica , Percepción del Tacto , Vibrisas/fisiología , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiónico/metabolismoRESUMEN
During early postnatal brain development, experience-driven delivery of AMPA receptors to synapses participates in the initial organization of cortical function. By combining virus-mediated in vivo gene delivery with in vitro whole cell recordings, we identified a subunit-specific developmental program of experience-driven AMPA receptor delivery to synapses in rat barrel cortex. We expressed green fluorescent protein (GFP)-tagged AMPA receptors (GFP-GluR1, or GFP-GluR4) into layer 2/3 pyramidal neurons at two distinct developmental periods, postnatal day (P)8-P10 and P12-P14. Two days after viral infection, acute brain slices were prepared, and synaptic transmission from layer 4 to layer 2/3 was analyzed by whole cell recordings. We found that whisker experience drives GluR4 but not GluR1 into these synapses early in postnatal development (P8-P10). However, at P12-14, GluR1 but not GluR4 is delivered into synapses by whisker experience. This precise developmental plan suggests unique plasticity properties endowed in different AMPA receptor subunits which shape the initial experience-driven organization of cortical function.