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1.
Front Aging Neurosci ; 14: 848380, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35250550

RESUMO

OBJECTIVE: Cortical electrical stimulation (CES) can modulate cortical excitability through a plasticity-like mechanism and is considered to have therapeutic potentials in Parkinson's disease (PD). However, the precise therapeutic value of such approach for PD remains unclear. Accordingly, we adopted a PD rat model to determine the therapeutic effects of CES. The current study was thus designed to identify the therapeutic potential of CES in PD rats. METHODS: A hemiparkinsonian rat model, in which lesions were induced using unilateral injection of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle, was applied to identify the therapeutic effects of long-term (4-week) CES with intermittent theta-burst stimulation (iTBS) protocol (starting 24 h after PD lesion observation, 1 session/day, 5 days/week) on motor function and neuroprotection. After the CES intervention, detailed functional behavioral tests including gait analysis, akinesia, open-field locomotor activity, apomorphine-induced rotation as well as degeneration level of dopaminergic neurons were performed weekly up to postlesion week 4. RESULTS: After the CES treatment, we found that the 4-week CES intervention ameliorated the motor deficits in gait pattern, akinesia, locomotor activity, and apomorphine-induced rotation. Immunohistochemistry and tyrosine hydroxylase staining analysis demonstrated that the number of dopamine neurons was significantly greater in the CES intervention group than in the sham treatment group. CONCLUSION: This study suggests that early and long-term CES intervention could reduce the aggravation of motor dysfunction and exert neuroprotective effects in a rat model of PD. Further, this preclinical model of CES may increase the scope for the potential use of CES and serve as a link between animal and PD human studies to further identify the therapeutic mechanism of CES for PD or other neurological disorders.

2.
Front Neural Circuits ; 15: 693073, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34194304

RESUMO

Objective: Individuals with different severities of traumatic brain injury (TBI) often suffer long-lasting motor, sensory, neurological, or cognitive disturbances. To date, no neuromodulation-based therapies have been used to manage the functional deficits associated with TBI. Cortical electrical stimulation (CES) has been increasingly developed for modulating brain plasticity and is considered to have therapeutic potential in TBI. However, the therapeutic value of such a technique for TBI is still unclear. Accordingly, an animal model of this disease would be helpful for mechanistic insight into using CES as a novel treatment approach in TBI. The current study aims to apply a novel CES scheme with a theta-burst stimulation (TBS) protocol to identify the therapeutic potential of CES in a weight drop-induced rat model of TBI. Methods: TBI rats were divided into the sham CES treatment group and CES treatment group. Following early and long-term CES intervention (starting 24 h after TBI, 1 session/day, 5 days/week) in awake TBI animals for a total of 4 weeks, the effects of CES on the modified neurological severity score (mNSS), sensorimotor and cognitive behaviors and neuroinflammatory changes were identified. Results: We found that the 4-week CES intervention significantly alleviated the TBI-induced neurological, sensorimotor, and cognitive deficits in locomotor activity, sensory and recognition memory. Immunohistochemically, we found that CES mitigated the glial fibrillary acidic protein (GFAP) activation in the hippocampus. Conclusion: These findings suggest that CES has significant benefits in alleviating TBI-related symptoms and represents a promising treatment for TBI.


Assuntos
Lesões Encefálicas Traumáticas , Transtornos Cognitivos , Disfunção Cognitiva , Animais , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/terapia , Cognição , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/terapia , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/terapia , Modelos Animais de Doenças , Estimulação Elétrica , Ratos
3.
Front Neural Circuits ; 15: 675365, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33994957

RESUMO

Objective: This study explored whether acupuncture affects the maintenance of long-term potentiation (LTP)-like plasticity induced by transcranial magnetic stimulation (TMS) and the acquisition of motor skills following repetitive sequential visual isometric pinch task (SVIPT) training. Methods: Thirty-six participants were recruited. The changes in the aftereffects induced by intermittent theta-burst stimulation (iTBS) and followed acupuncture were tested by the amplitude motor evoked potential (MEP) at pre-and-post-iTBS for 30 min and at acupuncture-in and -off for 30 min. Secondly, the effects of acupuncture on SVIPT movement in inducing error rate and learning skill index were tested. Results: Following one session of iTBS, the MEP amplitude was increased and maintained at a high level for 30 min. The facilitation of MEP was gradually decreased to the baseline level during acupuncture-in and did not return to a high level after needle extraction. The SVIPT-acupuncture group had a lower learning skill index than those in the SVIPT group, indicating that acupuncture intervention after SVIPT training may restrain the acquisition ability of one's learning skills. Conclusion: Acupuncture could reverse the LTP-like plasticity of the contralateral motor cortex induced by iTBS. Subsequent acupuncture may negatively affect the efficacy of the acquisition of learned skills in repetitive exercise training.


Assuntos
Terapia por Acupuntura , Córtex Motor , Potencial Evocado Motor , Humanos , Plasticidade Neuronal , Ritmo Teta , Estimulação Magnética Transcraniana
4.
Neural Plast ; 2021: 1763533, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34987572

RESUMO

Repetitive transcranial magnetic stimulation (rTMS) is a popular noninvasive technique for modulating motor cortical plasticity and has therapeutic potential for the treatment of Parkinson's disease (PD). However, the therapeutic benefits and related mechanisms of rTMS in PD are still uncertain. Accordingly, preclinical animal research is helpful for enabling translational research to explore an effective therapeutic strategy and for better understanding the underlying mechanisms. Therefore, the current study was designed to identify the therapeutic effects of rTMS on hemiparkinsonian rats. A hemiparkinsonian rat model, induced by unilateral injection of 6-hydroxydopamine (6-OHDA), was applied to evaluate the therapeutic potential of rTMS in motor functions and neuroprotective effect of dopaminergic neurons. Following early and long-term rTMS intervention with an intermittent theta burst stimulation (iTBS) paradigm (starting 24 h post-6-OHDA lesion, 1 session/day, 7 days/week, for a total of 4 weeks) in awake hemiparkinsonian rats, the effects of rTMS on the performance in detailed functional behavioral tests, including video-based gait analysis, the bar test for akinesia, apomorphine-induced rotational analysis, and tests of the degeneration level of dopaminergic neurons, were identified. We found that four weeks of rTMS intervention significantly reduced the aggravation of PD-related symptoms post-6-OHDA lesion. Immunohistochemically, the results showed that tyrosine hydroxylase- (TH-) positive neurons in the substantia nigra pars compacta (SNpc) and fibers in the striatum were significantly preserved in the rTMS treatment group. These findings suggest that early and long-term rTMS with the iTBS paradigm exerts neuroprotective effects and mitigates motor impairments in a hemiparkinsonian rat model. These results further highlight the potential therapeutic effects of rTMS and confirm that long-term rTMS treatment might have clinical relevance and usefulness as an additional treatment approach in individuals with PD.


Assuntos
Marcha/fisiologia , Córtex Motor/fisiopatologia , Destreza Motora/fisiologia , Neuroproteção/fisiologia , Doença de Parkinson Secundária/terapia , Estimulação Magnética Transcraniana/métodos , Animais , Corpo Estriado/metabolismo , Corpo Estriado/fisiopatologia , Modelos Animais de Doenças , Neurônios Dopaminérgicos/metabolismo , Masculino , Córtex Motor/metabolismo , Oxidopamina , Doença de Parkinson Secundária/induzido quimicamente , Doença de Parkinson Secundária/metabolismo , Doença de Parkinson Secundária/fisiopatologia , Ratos , Ratos Wistar , Tirosina 3-Mono-Oxigenase/metabolismo
5.
Breast Care (Basel) ; 15(4): 366-371, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32982646

RESUMO

OBJECTIVE: The aim of this study was to identify if breast reconstruction is a surgical risk factor for axillary web syndrome (AWS) in breast cancer (BC) patients. METHODS: The data of 207 patients who have been diagnosed with unilateral BC and who had mastectomy and lymph node dissection were retrospectively reviewed. Information of their clinical and pathological data, whether they had immediate -reconstruction and intraoperative radiotherapy, surgical methods, and postoperative complications during the 3 months after their surgery (AWS, lymphedema, seroma, and myofascial adhesion) were collected, and the incidence of AWS was compared between different surgical methods. RESULTS: The overall incidence of AWS was 48.8% in 207 patients. Of the 22 patients who received reconstruction, 19 developed AWS, yielding an incidence of 86%. Multivariate logistic regression modeling showed that patients who underwent reconstruction had a significantly higher incidence of AWS (odds ratio, 4.74), as did patients with postoperative complication of myofascial adhesion (odds ratio, 7.07). CONCLUSIONS: BC survivors after breast reconstruction are susceptible to AWS, and there is a significant association between myofascial adhesion and AWS. Our results can stimulate further investigation and provide an evidence base for the development of educational guidance for patients who plan to undergo breast reconstruction.

6.
Brain Stimul ; 13(3): 655-663, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32289694

RESUMO

BACKGROUND: Transcranial direct current stimulation (tDCS) has been proven to be able to modulate motor cortical plasticity might have potential as an alternative, adjunctive therapy for Parkinson's disease (PD). However, the efficacy of tDCS in PD is still uncertain. A disease animal model may be useful to clarify the existence of a treatment effect and to explore an effective therapeutic strategy using tDCS protocols. OBJECTIVE: The current study was designed to identify the comprehensive therapeutic effects of tDCS in 6-hydroxydopamine (6-OHDA)-lesioned PD rats. METHODS: Following early and long-term tDCS application (starting 24 h after PD lesion, 300 µA anodal tDCS, 20 min/day, 5 days/week) in awake PD animals for a total of 4 weeks, the effects of tDCS on motor and non-motor behaviors as well as dopaminergic neuron degeneration levels, were identified. RESULTS: We found that the 4-week tDCS intervention significantly alleviated 6-OHDA-induced motor deficits in locomotor activity, akinesia, gait pattern and anxiety-like behavior, but not in apomorphine-induced rotations, recognition memory and depression-like behavior. Immunohistochemically, tyrosine hydroxylase (TH)-positive neurons in the substantia nigra were significantly preserved in the tDCS intervention group. CONCLUSIONS: These results suggest that early and long-term tDCS could exert neuroprotective effects and reduce the aggravation of motor dysfunctions in a 6-OHDA-induced PD rat model. Furthermore, this preclinical model may enhance the promising possibility of the potential use of tDCS and serve as a translational platform to further identify the therapeutic mechanism of tDCS for PD or other neurological disorders.


Assuntos
Oxidopamina/toxicidade , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/prevenção & controle , Estimulação Transcraniana por Corrente Contínua/métodos , Animais , Eletrodos Implantados , Marcha/efeitos dos fármacos , Marcha/fisiologia , Masculino , Córtex Motor/efeitos dos fármacos , Córtex Motor/patologia , Transtornos Parkinsonianos/patologia , Ratos , Ratos Wistar , Fatores de Tempo , Resultado do Tratamento
7.
Behav Neurol ; 2019: 9278270, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31093303

RESUMO

The aim of this study was to investigate the time-dependent effects of acupuncture on the excitability and long-term potentiation- (LTP-) like plasticity induced by paired-associative stimulation (PAS) over the primary motor cortex (M1). The present examination is the first to report the influence of acupuncture on the motor-evoked potential (MEP) throughout the treatment process, including baseline (before acupuncture), the needle in situ, and the needle removal. Subsequently, the LTP-like plasticity induced by paired-associative stimulation (PAS) was explored, which consisted of 200 pairs of electrical stimulation of the ulnar nerve at the first dorsal interosseous (FDI), followed by transcranial magnetic stimulation (TMS) over the bilateral M1. TMS-MEP amplitudes over the bilateral M1 in resting conditions were measured throughout the whole treatment process. Finally, we confirmed the behavioral measurements. Significant changes were found in both the contralateral and ipsilateral acupuncture sizes as compared to the baseline values. Our results indicated that acupuncture modulated the excitability of M1, and the synaptic plasticity was time-dependent. We concluded that acupuncture should be combined with rehabilitation techniques to improve the motor function in stroke patients. Therefore, we put forward the combined application of the acupuncture timing and rehabilitation for higher therapeutic effectiveness. This trial was registered in the Chinese Clinical Trial Registry (registration no. ChiCTR-IPR-1900020515).


Assuntos
Terapia por Acupuntura/métodos , Potenciação de Longa Duração/fisiologia , Fatores de Tempo , Adolescente , Adulto , Povo Asiático/genética , China , Estimulação Elétrica/métodos , Eletromiografia/métodos , Potencial Evocado Motor/fisiologia , Feminino , Lateralidade Funcional , Mãos , Humanos , Masculino , Córtex Motor/fisiologia , Plasticidade Neuronal/fisiologia , Estimulação Magnética Transcraniana/métodos
8.
Neural Plast ; 2019: 4252943, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31949429

RESUMO

Transcranial direct current stimulation (tDCS) is a noninvasive technique for modulating neural plasticity and is considered to have therapeutic potential in neurological disorders. For the purpose of translational neuroscience research, a suitable animal model can be ideal for providing a stable condition for identifying mechanisms that can help to explore therapeutic strategies. Here, we developed a tDCS protocol for modulating motor excitability in anesthetized rats. To examine the responses of tDCS-elicited plasticity, the motor evoked potential (MEP) and MEP input-output (IO) curve elicited by epidural motor cortical electrical stimulus were evaluated at baseline and after 30 min of anodal tDCS or cathodal tDCS. Furthermore, a paired-pulse cortical electrical stimulus was applied to assess changes in the inhibitory network by measuring long-interval intracortical inhibition (LICI) before and after tDCS. In the results, analogous to those observed in humans, the present study demonstrates long-term potentiation- (LTP-) and long-term depression- (LTD-) like plasticity can be induced by tDCS protocol in anesthetized rats. We found that the MEPs were significantly enhanced immediately after anodal tDCS at 0.1 mA and 0.8 mA and remained enhanced for 30 min. Similarly, MEPs were suppressed immediately after cathodal tDCS at 0.8 mA and lasted for 30 min. No effect was noted on the MEP magnitude under sham tDCS stimulation. Furthermore, the IO curve slope was elevated following anodal tDCS and presented a trend toward diminished slope after cathodal tDCS. No significant differences in the LICI ratio of pre- to post-tDCS were observed. These results indicated that developed tDCS schemes can produce consistent, rapid, and controllable electrophysiological changes in corticomotor excitability in rats. This newly developed tDCS animal model could be useful to further explore mechanical insights and may serve as a translational platform bridging human and animal studies, establishing new therapeutic strategies for neurological disorders.


Assuntos
Potencial Evocado Motor/fisiologia , Córtex Motor/fisiologia , Plasticidade Neuronal/fisiologia , Estimulação Transcraniana por Corrente Contínua/métodos , Animais , Eletrodos Implantados , Masculino , Ratos , Ratos Sprague-Dawley , Estimulação Transcraniana por Corrente Contínua/instrumentação
9.
J Cell Sci ; 131(18)2018 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-30158176

RESUMO

Mammalian members of the ErbB family, including the epidermal growth factor receptor (EGFR), can regulate transcription, DNA replication and repair through nuclear entry of either the full-length proteins or their cleaved cytoplasmic domains. In cancer cells, these nuclear functions contribute to tumor progression and drug resistance. Here, we examined whether the single Drosophila EGFR can also localize to the nucleus. A chimeric EGFR protein fused at its cytoplasmic C-terminus to DNA-binding and transcriptional activation domains strongly activated transcriptional reporters when overexpressed in cultured cells or in vivo However, this activity was independent of cleavage and endocytosis. Without an exogenous activation domain, EGFR fused to a DNA-binding domain did not activate or repress transcription. Addition of the same DNA-binding and transcriptional activation domains to the endogenous Egfr locus through genome editing led to no detectable reporter expression in wild-type or oncogenic contexts. These results show that, when expressed at physiological levels, the cytoplasmic domain of the Drosophila EGFR does not have access to the nucleus. Therefore, nuclear EGFR functions are likely to have evolved after vertebrates and invertebrates diverged.


Assuntos
Núcleo Celular/metabolismo , Drosophila/metabolismo , Receptores ErbB/metabolismo , Animais
10.
Med Sci Monit ; 23: 6072-6081, 2017 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-29274273

RESUMO

BACKGROUND The role of nicotinic acetylcholine receptor alpha7 subunit (a7nAchR) in the treatment of acute cerebral ischemia by VNS has not been thoroughly clarified to date. Therefore, this study aimed to investigate the specific role of a7nAchR and explore whether this process is involved in the mechanisms of VNS-induced neuroprotection in rats undergoing permanent middle cerebral artery occlusion (PMCAO) surgery. MATERIAL AND METHODS Rats received a7nAChR antagonist (A) or antagonist placebo injection for control (AC), followed by PMCAO and VNS treatment, whereas the a7nAChR agonist (P) was utilized singly without VNS treatment but only with PMCAO pretreatment. The rats were randomly divided into 6 groups: sham PMCAO, PMCAO, PMCAO+VNS, PMCAO+VNS+A, PMCAO+VNS+AC, and PMCAO+P. Neurological function and cerebral infarct volume were measured to evaluate the level of brain injury at 24 h after PMCAO or PMCAO-sham. Moreover, the related proteins levels of a7nAChR, p-JAK2, and p-STAT3 in the ischemic penumbra were assessed by Western blot analysis. RESULTS Rats pretreated with VNS had significantly improved neurological function and reduced cerebral infarct volume after PMCAO injury (p<0.05). In addition, VNS enhanced the levels of a7nAchR, p-JAK2, and p-STAT3 in the ischemic penumbra (p<0.05). However, inhibition of a7nAchR not only attenuated the beneficial neuroprotective effects induced by VNS, but also decreased levels of p-JAK2 and p-STAT3. Strikingly, pharmacological activation of a7nAchR can partially substitute for VNS-induced beneficial neurological protection. CONCLUSIONS These results suggest that a7nAchR is a pivotal mediator of VNS-induced neuroprotective effects on PMCAO injury, which may be related to suppressed inflammation via activation of the a7nAchR/JAK2 anti-inflammatory pathway.


Assuntos
Isquemia Encefálica/terapia , Janus Quinase 2/metabolismo , Estimulação do Nervo Vago/métodos , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Animais , Lesões Encefálicas/tratamento farmacológico , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/metabolismo , Modelos Animais de Doenças , Infarto da Artéria Cerebral Média/metabolismo , Infarto da Artéria Cerebral Média/cirurgia , Inflamação/tratamento farmacológico , Masculino , Fármacos Neuroprotetores/uso terapêutico , Ratos , Ratos Sprague-Dawley , Fator de Transcrição STAT3/metabolismo , Nervo Vago/metabolismo , Receptor Nicotínico de Acetilcolina alfa7/agonistas , Receptor Nicotínico de Acetilcolina alfa7/antagonistas & inibidores
11.
Medicine (Baltimore) ; 95(30): e4032, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27472676

RESUMO

In the present study, we adopted a novel method-local diffusion homogeneity (LDH)-to characterize the structure feature in mesial temporal lobe epilepsy (MTLE). Diffusion-weighted images were acquired from 11 left MTLE patients, 16 right MTLE patients, and 20 healthy controls from May 2014 to January 2015. Local diffusion homogeneity was compared among patient groups and controls by 2 sample t test. The discriminative value of LDH abnormalities was examined by receiver operating characteristic (ROC) curve analysis. Correlations with disease duration and onset age in both patient groups were assessed using Pearson's coefficient. Both patient groups exhibited lower LDH in the anterior corpus callosum (P < 0.05, corrected), and this regional anomaly exhibited excellent classification performance in left MTLE patients (sensitivity = 82%, specificity = 100%), right MTLE patients (sensitivity = 81%, specificity = 90%), and the entire patient cohort (sensitivity = 82%, specificity = 95%). In summary, left and right MTLE patients show common pathological changes in the anterior corpus callosum. This regional LDH abnormality is a potential quantitative biomarker for MTLE.


Assuntos
Corpo Caloso/patologia , Imagem de Difusão por Ressonância Magnética , Epilepsia do Lobo Temporal/patologia , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Estudos Prospectivos , Curva ROC , Sensibilidade e Especificidade
12.
Development ; 142(8): 1480-91, 2015 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-25790850

RESUMO

Endocytic trafficking of signaling receptors is an important mechanism for limiting signal duration. Components of the Endosomal Sorting Complexes Required for Transport (ESCRT), which target ubiquitylated receptors to intra-lumenal vesicles (ILVs) of multivesicular bodies, are thought to terminate signaling by the epidermal growth factor receptor (EGFR) and direct it for lysosomal degradation. In a genetic screen for mutations that affect Drosophila eye development, we identified an allele of Vacuolar protein sorting 4 (Vps4), which encodes an AAA ATPase that interacts with the ESCRT-III complex to drive the final step of ILV formation. Photoreceptors are largely absent from Vps4 mutant clones in the eye disc, and even when cell death is genetically prevented, the mutant R8 photoreceptors that develop fail to recruit surrounding cells to differentiate as R1-R7 photoreceptors. This recruitment requires EGFR signaling, suggesting that loss of Vps4 disrupts the EGFR pathway. In imaginal disc cells mutant for Vps4, EGFR and other receptors accumulate in endosomes and EGFR target genes are not expressed; epistasis experiments place the function of Vps4 at the level of the receptor. Surprisingly, Vps4 is required for EGFR signaling even in the absence of Shibire, the Dynamin that internalizes EGFR from the plasma membrane. In ovarian follicle cells, in contrast, Vps4 does not affect EGFR signaling, although it is still essential for receptor degradation. Taken together, these findings indicate that Vps4 can promote EGFR activity through an endocytosis-independent mechanism.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Drosophila/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Receptores ErbB/metabolismo , Adenosina Trifosfatases/genética , Animais , Drosophila , Proteínas de Drosophila/genética , Dinaminas/genética , Dinaminas/metabolismo , Endocitose/genética , Endocitose/fisiologia , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Receptores ErbB/genética , Masculino , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
13.
Dongwuxue Yanjiu ; 35(6): 500-9, 2014 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-25465088

RESUMO

Under free field conditions, we used single unit extracellular recording to study the detection of acoustic signals by neurons in the ventral nucleus of the lateral lemniscus (VNLL) in Kunming mouse (Mus musculus). The results indicate two types of firing patterns in VNLL neurons: onset and sustained. The first spike latency (FSL) of onset neurons was shorter than that of sustained neurons. With increasing sound intensity, the FSL of onset neurons remained stable and that of sustained neurons was shortened, indicating that onset neurons are characterized by precise timing. By comparing the values of Q10 and Q30 of the frequency tuning curve, no differences between onset and sustained neurons were found, suggesting that firing pattern and frequency tuning are not correlated. Among the three types of rate-intensity function (RIF) found in VNLL neurons, the proportion of monotonic RIF is the largest, followed by saturated RIF, and non-monotonic RIF. The dynamic range (DR) in onset neurons was shorter than in sustained neurons, indicating different capabilities in intensity tuning of different firing patterns and that these differences are correlated with the type of RIF. Our results also show that the best frequency of VNLL neurons was negatively correlated with depth, supporting the view point that the VNLL has frequency topologic organization.


Assuntos
Estimulação Acústica , Córtex Auditivo/citologia , Neurônios/fisiologia , Núcleos Ventrais do Tálamo/citologia , Animais , Córtex Auditivo/fisiologia , Estimulação Elétrica , Potenciais da Membrana/fisiologia , Camundongos
14.
Sheng Li Xue Bao ; 66(3): 358-64, 2014 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-24964854

RESUMO

The ventral nucleus of the lateral lemniscus (VNLL) is an important nucleus in the central auditory pathway which connects the lower brainstem and the midbrain inferior colliculus (IC). Previous studies have demonstrated that neurons in the VNLL could respond to sound signal parameters. Frequency tuning curves (FTCs) of VNLL neurons are generally wider than FTCs of IC neurons, suggesting that the VNLL does not enhance abilities of frequency discrimination and coding. Two types of rate-intensity functions (RIFs) are found in the VNLL: monotonic and non-monotonic RIFs. Intensity-tuning of VNLL neurons are affected by the temporal firing patterns during processing and encoding intensity. There are multiple temporal firing patterns in VNLL neurons. Onset pattern has a precise timing characteristic which is well suited to encode temporal features of stimuli, and also very important to animal behavior including bat's echolocation. The VNLL accepts inputs from lower nuclei, uploads glycine inhibitory outputs to IC, and modulates response characteristics generating and acoustic signal processing of IC neurons. Recent research suggests that fast inhibitory projection from the VNLL may delay the first spike latency of IC neurons, and the delayed inhibitory projection from the VNLL may mediate the temporal firing patterns of IC neurons. But how inhibitory inputs from the VNLL integrate in IC, and how inhibitory inputs from the VNLL enhance the ability of detecting sound signal of IC neurons are not very clear and need more direct evidence at the level of neurons. These questions will help further understand the role of upload during IC processes acoustic signal, which are our research target in the future. This article reviews the current literature regarding the roles of the VNLL in sound signal processing and the auditory ascending transmission, including advances in the relevant research in our laboratory.


Assuntos
Vias Auditivas , Neurônios/fisiologia , Ponte/citologia , Estimulação Acústica , Animais , Quirópteros , Ecolocação
15.
J Cell Sci ; 126(Pt 19): 4469-78, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23902690

RESUMO

Epidermal growth factor receptor (EGFR) ligands undergo a complex series of processing events during their maturation to active signaling proteins. Like its mammalian homologs, the predominant Drosophila EGFR ligand Spitz is produced as a transmembrane pro-protein. In the secretory pathway, Spitz is cleaved within its transmembrane domain to release the extracellular signaling domain. This domain is modified with an N-terminal palmitate group that tethers it to the plasma membrane. We found that the pro-protein can reach the cell surface in the absence of proteolysis, but that it fails to activate the EGFR. To address why the transmembrane pro-protein is inactive, whereas membrane association through the palmitate group promotes activity, we generated a panel of chimeric constructs containing the Spitz extracellular region fused to exogenous transmembrane proteins. Although the orientation of the EGF domain and its distance from the plasma membrane varies in these chimeras, they are all active in vivo. Thus, tethering Spitz to the membrane via a transmembrane domain at either terminus does not prevent activity. Conversely, removing the N-terminal palmitate group from the C-terminally tethered pro-protein does not render it active. Furthermore, we show that the Spitz transmembrane pro-protein can activate the EGFR in a tissue culture assay, indicating that its failure to signal in vivo is not due to structural features. In polarized imaginal disc cells, unprocessed Spitz pro-protein localizes to apical puncta, whereas the active chimeric Spitz constructs are basolaterally localized. Taken together, our data support the model that localized trafficking of the pro-protein restricts its ability to activate the receptor in polarized tissues.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Receptores ErbB/metabolismo , Proteínas de Membrana/metabolismo , Animais , Drosophila/genética , Proteínas de Drosophila/genética , Fator de Crescimento Epidérmico/genética , Receptores ErbB/genética , Ligantes , Proteínas de Membrana/genética , Transdução de Sinais , Transfecção
16.
Chin Med J (Engl) ; 126(12): 2361-7, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23786955

RESUMO

BACKGROUND: Functional electrical stimulation (FES) is known to promote the recovery of motor function in rats with ischemia and to upregulate the expression of growth factors which support brain neurogenesis. In this study, we investigated whether postischemic FES could improve functional outcomes and modulate neurogenesis in the subventricular zone (SVZ) after focal cerebral ischemia. METHODS: Adult male Sprague-Dawley rats with permanent middle cerebral artery occlusion (MCAO) were randomly assigned to the control group, the placebo stimulation group, and the FES group. The rats in each group were further assigned to one of four therapeutic periods (1, 3, 7, or 14 days). FES was delivered 48 hours after the MCAO procedure and divided into two 10-minute sessions on each day of treatment with a 10-minute rest between them. Two intraperitoneal injections of bromodeoxyuridine (BrdU) were given 4 hours apart every day beginning 48 hours after the MCAO. Neurogenesis was evaluated by immunofuorescence staining. Wnt-3 which is strongly implicated in the proliferation and differentiation of neural stem cells (NSCs) was investigated by Western blotting analysis. The data were subjected to one- way analysis of variance (ANOVA), followed by a Tukey/Kramer or Dunnett post hoc test. RESULTS: FES significantly increased the number of BrdU-positive cells and BrdU/glial fibrillary acidic protein double- positive neural progenitor cells in the SVZ on days 7 and 14 of the treatment (P < 0.05). The number of BrdU/doublecortin (DCX) double-positive migrating neuroblast cells in the ipsilateral SVZ on day 14 of the FES treatment group ((522.77 ± 33.32) cells/mm(2)) was significantly increased compared with the control group ((262.58 ± 35.11) cells/mm(2), P < 0.05) and the placebo group ((266.17 ± 47.98) cells/mm(2), P < 0.05). However, only a few BrdU/neuron-specific nuclear protein-positive cells were observed by day 14 of the treatment. At day 7, Wnt-3 was upregulated in the ipsilateral SVZs of the rats receiving FES ((0.44 ± 0.05)%) compared with those of the control group rats ((0.31 ± 0.02)%, P < 0.05) or the placebo group rats ((0.31 ± 0.04)%, P < 0.05). At day 14, the corresponding values were (0.56 ± 0.05)% in the FES group compared with those of the control group rats ((0.50 ± 0.06)%, P < 0.05) or the placebo group rats ((0.48 ± 0.06)%, P < 0.05). CONCLUSION: FES augments the proliferation, differentiation, and migration of NSCs and thus promotes neurogenesis, which may be related to the improvement of neurological outcomes.


Assuntos
Proliferação de Células , Ventrículos Cerebrais/fisiopatologia , Terapia por Estimulação Elétrica , Células-Tronco Neurais/fisiologia , Neurogênese , Acidente Vascular Cerebral/terapia , Animais , Bromodesoxiuridina/metabolismo , Proteína Duplacortina , Proteína Glial Fibrilar Ácida/análise , Masculino , Ratos , Ratos Sprague-Dawley , Acidente Vascular Cerebral/fisiopatologia , Proteína Wnt3A/análise
17.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 23(3): 323-5, 2006 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-16767675

RESUMO

OBJECTIVE: To investigate the point mutations of mitochondrial DNA in the families with hereditary ataxia. METHODS: Polymerase chain reaction and single strand conformation polymorphism (SSCP) were used to analyze the mitochondrial DNA extracted from human peripheral white blood cells from the families with HA and 35 normal controls. Sequencing was performed to search the point mutations in mitochondrial DNA of those subjects whose results of SSCP were abnormal. RESULTS: A mitochondrial DNA point mutation 11893(A>G) was identified in 2 patients and 1 family member without symptoms. CONCLUSION: A new point mutation 11893(A>G) of detected mitochondrial DNA may be relative to hereditary ataxia.


Assuntos
DNA Mitocondrial/genética , Mutação Puntual , Degenerações Espinocerebelares/genética , Idoso , Sequência de Bases , China , Análise Mutacional de DNA , DNA Mitocondrial/química , Saúde da Família , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples
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