Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 446
Filter
1.
Neuroscience Bulletin ; (6): 113-134, 2022.
Article in English | WPRIM | ID: wpr-922681

ABSTRACT

Mutations of the X-linked methyl-CpG-binding protein 2 (MECP2) gene in humans are responsible for most cases of Rett syndrome (RTT), an X-linked progressive neurological disorder. While genome-wide screens in clinical trials have revealed several putative RTT-associated mutations in MECP2, their causal relevance regarding the functional regulation of MeCP2 at the etiologic sites at the protein level requires more evidence. In this study, we demonstrated that MeCP2 was dynamically modified by O-linked-β-N-acetylglucosamine (O-GlcNAc) at threonine 203 (T203), an etiologic site in RTT patients. Disruption of the O-GlcNAcylation of MeCP2 specifically at T203 impaired dendrite development and spine maturation in cultured hippocampal neurons, and disrupted neuronal migration, dendritic spine morphogenesis, and caused dysfunction of synaptic transmission in the developing and juvenile mouse cerebral cortex. Mechanistically, genetic disruption of O-GlcNAcylation at T203 on MeCP2 decreased the neuronal activity-induced induction of Bdnf transcription. Our study highlights the critical role of MeCP2 T203 O-GlcNAcylation in neural development and synaptic transmission potentially via brain-derived neurotrophic factor.


Subject(s)
Animals , Humans , Methyl-CpG-Binding Protein 2/metabolism , Mice , Neurodevelopmental Disorders/genetics , Rett Syndrome/genetics , Synaptic Transmission , Threonine
2.
Gac. méd. Méx ; 156(1): 60-66, ene.-feb. 2020. tab, graf
Article in English, Spanish | LILACS | ID: biblio-1249871

ABSTRACT

Resumen El síndrome X frágil es la condición monogenética que produce más casos de autismo y de discapacidad intelectual. La repetición de tripletes CGG (> 200) y su metilación conllevan el silenciamiento del gen FMR1. La proteína FMRP (producto del gen FMR1) interacciona con los ribosomas, controlando la traducción de mensajeros específicos y su pérdida produce alteraciones de la conectividad sináptica. El tamizaje de síndrome X frágil se realiza por reacción en cadena de la polimerasa. La recomendación actual de la Academia Americana de Pediatría es realizar pruebas a quienes presenten discapacidad intelectual, retraso global del desarrollo o antecedentes familiares de afección por la mutación o premutación. Países hispanos como Colombia, Chile y España reportan altas prevalencias de síndrome X frágil y han creado asociaciones o corporaciones nacionales de X frágil que buscan acercar a los pacientes a redes disponibles de diagnóstico y tratamiento.


Abstract Fragile X syndrome is the monogenetic condition that produces more cases of autism and intellectual disability. The repetition of CGG triplets (> 200) and their methylation entail the silencing of the FMR1 gene. The FMRP protein (product of the FMR1 gene) interacts with ribosomes by controlling the translation of specific messengers, and its loss causes alterations in synaptic connectivity. Screening for fragile X syndrome is performed by polymerase chain reaction. Current recommendation of the American Academy of Pediatrics is to test individuals with intellectual disability, global developmental retardation or with a family history of presence of the mutation or premutation. Hispanic countries such as Colombia, Chile and Spain report high prevalence of fragile X syndrome and have created fragile X national associations or corporations that seek to bring patients closer to available diagnostic and treatment networks.


Subject(s)
Humans , Male , Child, Preschool , Autistic Disorder/genetics , Fragile X Mental Retardation Protein/genetics , Fragile X Syndrome/genetics , Intellectual Disability/genetics , Pedigree , Phenotype , Ribosomes/metabolism , Attention Deficit Disorder with Hyperactivity/genetics , Sex Factors , Genetic Testing , Synaptic Transmission , Gene Silencing , Fragile X Mental Retardation Protein/metabolism , Checklist , Fragile X Syndrome/complications , Fragile X Syndrome/diagnosis , Fragile X Syndrome/therapy , Mutation
3.
Acta Physiologica Sinica ; (6): 391-398, 2020.
Article in Chinese | WPRIM | ID: wpr-827049

ABSTRACT

Under physiological conditions, the motility of smooth muscle in digestive tract is mainly regulated by enteric nervous system (ENS). However, how neural signal is transmitted to smooth muscle is not fully understood. Autonomic nerve endings in the smooth muscle layer form large number of varicosities which contain neurotransmitters. It was considered that nerve pulses arriving at the varicosities may cause the release of neurotransmitters, which may diffuse to the smooth muscle cells to induce contractile or relaxant responses. Over the past decade, a new understanding of the neurotransmission between ENS and smooth muscle has emerged, which emphasizes the role of a functional syncytium consisting of the interstitial cells of Cajal (ICC), the platelet-derived growth factor receptor α positive (PDGFRα) cells and the smooth muscle cells. Within the syncytium, purine neurotransmitters bind to P2Y1 receptors on PDGFRα cells, activating small-conductance calcium activated potassium channel (SK3) to hyperpolarize PDGFRα cells, and thus hyperpolarize smooth muscle cells through gap junction, resulting in relaxation of smooth muscle. In this paper, we review the research progress in the field of inhibitory purinergic neurotransmission in the gastrointestinal tract.


Subject(s)
Interstitial Cells of Cajal , Muscle, Smooth , Myocytes, Smooth Muscle , Receptor, Platelet-Derived Growth Factor alpha , Synaptic Transmission
4.
Acta Physiologica Sinica ; (6): 547-554, 2019.
Article in Chinese | WPRIM | ID: wpr-777157

ABSTRACT

The aim of the present study was to reveal the role of cortical-striatum postsynaptic dopamine D2 receptor (D2R) in improving motor behavioral dysfunction in Parkinson's disease (PD) mice by exercise. C57/BL6 male adult mice were randomly divided into control, PD and PD plus exercise groups. The mice were injected with 6-OHDA in striatum to establish a unilateral injury PD model. The exercise intervention program was uniform speed running (16 m/min, 40 min/d, 5 d per week for 4 weeks). Autonomic activity of mice was tested by open field test. Cortical-striatum synaptic transmission efficiency was assessed by peak amplitude of field excitatory postsynaptic potential (fEPSP) recorded from in vitro brain slides. Meanwhile, the effects of D2R agonist on autonomic activity and cortical-striatal synaptic transmission were observed. The results showed that, compared with PD group, PD plus exercise group exhibited significantly increased autonomic motor distance and proportion of fast-moving (P < 0.05), as well as decreased maximum amplitude of fEPSP under increasing stimulation intensity (0.75-3.00 pA) (P < 0.05) and slope of stimulus-response curve. Compared with PD mice without D2R agonist, the movement distance and rapid movement ratio of PD mice treated with D2R agonist were increased significantly (P < 0.05), whereas fEPSP peak amplitude (P < 0.05) and the slope of stimulus-response curve were decreased. These results indicate that either early exercise intervention or D2R agonist treatment can inhibit the abnormal increase of cortical-striatum synaptic transmission and improve the autonomic motor ability in PD mice, suggesting that the cortical-striatum synaptic D2R may be an important molecular target for exercise to improve the autonomic motor ability of PD mice.


Subject(s)
Animals , Corpus Striatum , Physiology , Male , Mice , Mice, Inbred C57BL , Oxidopamine , Parkinson Disease , Therapeutics , Physical Conditioning, Animal , Random Allocation , Receptors, Dopamine D2 , Physiology , Synaptic Transmission
5.
Acta Physiologica Sinica ; (6): 261-270, 2019.
Article in English | WPRIM | ID: wpr-777190

ABSTRACT

It was reported that α7 nicotinic acetylcholine receptor (α7-nAChR) knockout (α7 KO) mice showed few functional phenotypes. The purpose of this study was to investigate the effect of α7 KO on the electrophysiological characteristics of hippocampus in mice. The effect of α7 KO on hippocampal CA3-CA1 synaptic transmission in mice was evaluated by standard extracellular field potential recordings. The electrophysiological phenotype of γ-aminobutyrate A receptors (GABA-Rs) of single hippocampal neuron was detected by perforated patch-clamp recordings. The results showed that, the slope of field excitatory postsynaptic potential (fEPSP) and carbachol-induced theta oscillation were significantly decreased in the hippocampal CA1 neurons of α7 KO mice, compared with those of wild type mice. Under the treatment of GABA-R agonist muscimol, the I-V curves of both the hippocampal CA1 and CA3 neurons of α7 KO mice shifted towards depolarizing direction obviously, compared with those of wild type mice. These results suggest that the hippocampal CA3-CA1 synaptic transmission in α7 KO mice was significantly impaired and GABA-R maturation was significantly delayed, indicating that the deletion of α7-nAChR gene could significantly change the electrophysiological function of the hippocampus. The results may provide a new understanding of the role of α7-nAChR in hippocampal function and associated diseases.


Subject(s)
Animals , Hippocampus , Cell Biology , Mice , Mice, Knockout , Neurons , Physiology , Phenotype , Synaptic Transmission , alpha7 Nicotinic Acetylcholine Receptor , Physiology
6.
Article | WPRIM | ID: wpr-763553

ABSTRACT

OBJECTIVE: This study aimed to investigate the long-term effects of aripiprazole treatment during adolescence on behavior, cognitive function, and dopamine D2 receptor (D2R) expression in adult rats. METHODS: Adolescent male Sprague-Dawley rats were injected intraperitoneally with aripiprazole, risperidone, or vehicle control for 3 weeks (postnatal day 36–56). After a 2-week washout period, locomotion, anxiety, and spatial working memory were evaluated in adulthood (postnatal day 71–84), using an open field test, elevated plus maze, and Y-maze, respectively. In addition, we assessed D2R levels in the dorsolateral and medial prefrontal cortex (PFC), dorsal and ventral striatum, and hippocampus using western blot analysis. RESULTS: Spontaneous alternation performance (SAP) in the Y-maze, a measure of spatial working memory, differed significantly among the 3 groups (F = 3.89, p = 0.033). A post-hoc test confirmed that SAP in the aripiprazole group was significantly higher than that in the risperidone group (post-hoc test p = 0.013). D2R levels in the medial PFC (F = 8.72, p = 0.001) and hippocampus (F = 13.54, p < 0.001) were different among the 3 groups. D2R levels in the medial PFC and hippocampus were significantly lower in the aripiprazole-treated rats than that in the risperidone-treated rats (post-hoc test p = 0.025 and p < 0.001, respectively) and controls (post-hoc test p < 0.001, all). CONCLUSION: This study showed that aripiprazole treatment in adolescence could influence cognitive function and dopaminergic neurotransmission into early adulthood.


Subject(s)
Adolescent , Adult , Animals , Anxiety , Aripiprazole , Blotting, Western , Cognition , Dopamine , Hippocampus , Humans , Locomotion , Male , Memory, Short-Term , Models, Animal , Prefrontal Cortex , Rats , Rats, Sprague-Dawley , Receptors, Dopamine D2 , Risperidone , Synaptic Transmission , Ventral Striatum
7.
Article in English | WPRIM | ID: wpr-763527

ABSTRACT

OBJECTIVE: Garcinia mangostana Linn., commonly known as mangosteen, is a tropical fruit with a thick pericarp rind containing bioactive compounds that may be beneficial as an adjunctive treatment for schizophrenia. The biological underpinnings of schizophrenia are believed to involve altered neurotransmission, inflammation, redox systems, mitochondrial dysfunction, and neurogenesis. Mangosteen pericarp contains xanthones which may target these biological pathways and improve symptoms; this is supported by preclinical evidence. Here we outline the protocol for a double-blind randomized placebo-controlled trial evaluating the efficacy of adjunctive mangosteen pericarp (1,000 mg/day), compared to placebo, in the treatment of schizophrenia. METHODS: We aim to recruit 150 participants across two sites (Geelong and Brisbane). Participants diagnosed with schizophrenia or schizoaffective disorder will be randomized to receive 24 weeks of either adjunctive 1,000 mg/day of mangosteen pericarp or matched placebo, in addition to their usual treatment. The primary outcome measure is mean change in the Positive and Negative Symptom Scale (total score) over the 24 weeks. Secondary outcomes include positive and negative symptoms, general psychopathology, clinical global severity and improvement, depressive symptoms, life satisfaction, functioning, participants reported overall improvement, substance use, cognition, safety and biological data. A 4-week post treatment interview at week 28 will explore post-discontinuations effects. RESULTS: Ethical and governance approvals were gained and the trial commenced. CONCLUSION: A positive finding in this study has the potential to provide a new adjunctive treatment option for people with schizophrenia and schizoaffective disorder. It may also lead to a greater understanding of the pathophysiology of the disorder.


Subject(s)
Cognition , Depression , Fruit , Garcinia mangostana , Garcinia , Inflammation , Neurogenesis , Outcome Assessment, Health Care , Oxidation-Reduction , Oxidative Stress , Psychopathology , Psychotic Disorders , Schizophrenia , Synaptic Transmission , Xanthones
8.
Article in English | WPRIM | ID: wpr-763028

ABSTRACT

Limonene is a cyclic terpene found in citrus essential oils and inhibits methamphetamine-induced locomotor activity. Drug dependence is a severe neuropsychiatric condition that depends in part on changes in neurotransmission and neuroadaptation, induced by exposure to recreational drugs such as morphine and methamphetamine. In this study, we investigated the effects of limonene on the psychological dependence induced by drug abuse. The development of sensitization, dopamine receptor supersensitivity, and conditioned place preferences in rats was measured following administration of limonene (10 or 20 mg/kg) and methamphetamine (1 mg/kg) for 4 days. Limonene inhibits methamphetamine-induced sensitization to locomotor activity. Expression of dopamine receptor supersensitivity induced by apomorphine, a dopamine receptor agonist, was significantly reduced in limonene-pretreated rats. However, there was no significant difference in methamphetamine-induced conditioned place preferences between the limonene and control groups. These results suggest that limonene may ameliorate drug addiction-related behaviors by regulating postsynaptic dopamine receptor supersensitivity.


Subject(s)
Animals , Apomorphine , Citrus , Dopamine Agonists , Dopamine , Methamphetamine , Morphine , Motor Activity , Oils, Volatile , Rats , Receptors, Dopamine , Illicit Drugs , Substance-Related Disorders , Synaptic Transmission
9.
Article in English | WPRIM | ID: wpr-761804

ABSTRACT

It is known that top-down associative inputs terminate on distal apical dendrites in layer 1 while bottom-up sensory inputs terminate on perisomatic dendrites of layer 2/3 pyramidal neurons (L2/3 PyNs) in primary sensory cortex. Since studies on synaptic transmission in layer 1 are sparse, we investigated the basic properties and cholinergic modulation of synaptic transmission in layer 1 and compared them to those in perisomatic dendrites of L2/3 PyNs of rat primary visual cortex. Using extracellular stimulations of layer 1 and layer 4, we evoked excitatory postsynaptic current/potential in synapses in distal apical dendrites (L1-EPSC/L1-EPSP) and those in perisomatic dendrites (L4-EPSC/L4-EPSP), respectively. Kinetics of L1-EPSC was slower than that of L4-EPSC. L1-EPSC showed presynaptic depression while L4-EPSC was facilitating. In contrast, inhibitory postsynaptic currents showed similar paired-pulse ratio between layer 1 and layer 4 stimulations with depression only at 100 Hz. Cholinergic stimulation induced presynaptic depression by activating muscarinic receptors in excitatory and inhibitory synapses to similar extents in both inputs. However, nicotinic stimulation enhanced excitatory synaptic transmission by ~20% in L4-EPSC. Rectification index of AMPA receptors and AMPA/NMDA ratio were similar between synapses in distal apical and perisomatic dendrites. These results provide basic properties and cholinergic modulation of synaptic transmission between distal apical and perisomatic dendrites in L2/3 PyNs of the visual cortex, which might be important for controlling information processing balance depending on attentional state.


Subject(s)
Animals , Electronic Data Processing , Dendrites , Depression , Inhibitory Postsynaptic Potentials , Kinetics , Pyramidal Cells , Rats , Receptors, AMPA , Receptors, Muscarinic , Synapses , Synaptic Transmission , Visual Cortex
10.
Psychiatry Investigation ; : 177-184, 2019.
Article in English | WPRIM | ID: wpr-760920

ABSTRACT

OBJECTIVE: Schizophrenia is a disabling disorder of unknown aetiology, lacking definite diagnostic method and cure. A reliable biological marker of schizophrenia is highly demanded, for which traceable immune mediators in blood could be promising candidates. We aimed to gather the best findings of neuroinflammatory markers for first-episode psychosis (FEP). METHODS: We performed an extensive narrative review of online literature on inflammation-related markers found in human FEP patients only. RESULTS: Changes to cytokine levels have been increasingly reported in schizophrenia. The peripheral levels of IL-1 (or its receptor antagonist), soluble IL-2 receptor, IL-4, IL-6, IL-8, and TNF-α have been frequently reported as increased in FEP, in a suggestive continuum from high-risk stages for psychosis. Microglia and astrocytes establish the link between this immune signalling and the synthesis of noxious tryptophan catabolism products, that cause structural damage and directly hamper normal neurotransmission. Amongst these, only 3-hydroxykynurenine has been consistently described in the blood of FEP patients. CONCLUSION: Peripheral molecules stemming from brain inflammation might provide insightful biomarkers of schizophrenia, as early as FEP or even prodromal phases, although more time- and clinically-adjusted studies are essential for their validation.


Subject(s)
Astrocytes , Biomarkers , Encephalitis , Humans , Interleukin-1 , Interleukin-4 , Interleukin-6 , Interleukin-8 , Metabolism , Methods , Microglia , Polytetrafluoroethylene , Psychotic Disorders , Receptors, Interleukin-2 , Schizophrenia , Synaptic Transmission , Tryptophan
11.
Article in English | WPRIM | ID: wpr-739661

ABSTRACT

Dysregulation of excitatory neurotransmission has been implicated in the pathogenesis of neuropsychiatric disorders. Pharmacological inhibition of N-methyl-D-aspartate (NMDA) receptors is widely used to model neurobehavioral pathologies and underlying mechanisms. There is ample evidence that overstimulation of NMDA-dependent neurotransmission may induce neurobehavioral abnormalities, such as repetitive behaviors and hypersensitization to nociception and cognitive disruption, pharmacological modeling using NMDA has been limited due to the induction of neurotoxicity and blood brain barrier breakdown, especially in young animals. In this study, we examined the effects of intraperitoneal NMDA-administration on nociceptive and repetitive behaviors in ICR mice. Intraperitoneal injection of NMDA induced repetitive grooming and tail biting/licking behaviors in a dose- and age-dependent manner. Nociceptive and repetitive behaviors were more prominent in juvenile mice than adult mice. We did not observe extensive blood brain barrier breakdown or neuronal cell death after peritoneal injection of NMDA, indicating limited neurotoxic effects despite a significant increase in NMDA concentration in the cerebrospinal fluid. These findings suggest that the observed behavioral changes were not mediated by general NMDA toxicity. In the hot plate test, we found that the latency of paw licking and jumping decreased in the NMDA-exposed mice especially in the 75 mg/kg group, suggesting increased nociceptive sensitivity in NMDA-treated animals. Repetitive behaviors and increased pain sensitivity are often comorbid in psychiatric disorders (e.g., autism spectrum disorder). Therefore, the behavioral characteristics of intraperitoneal NMDA-administered mice described herein may be valuable for studying the mechanisms underlying relevant disorders and screening candidate therapeutic molecules.


Subject(s)
Adult , Animals , Autistic Disorder , Blood-Brain Barrier , Cell Death , Cerebrospinal Fluid , Grooming , Humans , Injections, Intraperitoneal , Mass Screening , Mice , Mice, Inbred ICR , N-Methylaspartate , Neurons , Nociception , Pathology , Synaptic Transmission , Tail
12.
Article in English | WPRIM | ID: wpr-739533

ABSTRACT

The neuronal activity-dependent change in the manner in which light is absorbed or scattered in brain tissue is called the intrinsic optical signal (IOS), and provides label-free, minimally invasive, and high spatial (~100 µm) resolution imaging for visualizing neuronal activity patterns. IOS imaging in isolated brain slices measured at an infrared wavelength (>700 nm) has recently been attributed to the changes in light scattering and transmittance due to aquaporin-4 (AQP4)-dependent astrocytic swelling. The complexity of functional interactions between neurons and astrocytes, however, has prevented the elucidation of the series of molecular mechanisms leading to the generation of IOS. Here, we pharmacologically dissected the IOS in the acutely prepared brain slices of the stratum radiatum of the hippocampus, induced by 1 s/20 Hz electrical stimulation of Schaffer-collateral pathway with simultaneous measurement of the activity of the neuronal population by field potential recordings. We found that 55% of IOSs peak upon stimulation and originate from postsynaptic AMPA and NMDA receptors. The remaining originated from presynaptic action potentials and vesicle fusion. Mechanistically, the elevated extracellular glutamate and K⁺ during synaptic transmission were taken up by astrocytes via a glutamate transporter and quinine-sensitive K2P channel, followed by an influx of water via AQP-4. We also found that the decay of IOS is mediated by the DCPIB- and NPPB-sensitive anion channels in astrocytes. Altogether, our results demonstrate that the functional coupling between synaptic activity and astrocytic transient volume change during excitatory synaptic transmission is the major source of IOS.


Subject(s)
Action Potentials , alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid , Amino Acid Transport System X-AG , Astrocytes , Brain , Electric Stimulation , Glutamic Acid , Hippocampus , Jupiter , Neurons , Receptors, N-Methyl-D-Aspartate , Synaptic Transmission , Water
13.
Article in English | WPRIM | ID: wpr-741827

ABSTRACT

PURPOSE: Malnutrition may influence neurocognitive development in children by directly affecting the brain structural development, or indirectly by affecting the children's cognition experience. Malnutrition alters the cell numbers, cell migration, synaptogenesis, and neurotransmission due to inadequate availability of necessary micronutrients to support cell growth. We aimed to analyze neurocognitive development in infants with malnutrition and its association with long chain polyunsaturated fatty acids (LC-PUFA), micronutrients levels and magnetic resonance spectroscopy (MRS) findings. METHODS: The study included two groups; group 1, infants with malnutrition (n=24), group 2; healthy infants (n=21). Peripheral blood was obtained from the participants for studying micronutrients and LC-PUFA levels. The neurocognitive development was analyzed by the use of an Ankara Developmental Screening Inventory test. MRS were performed on all infants. RESULTS: All parameters of neurocognitive development and serum calcium (9.6±0.9 mg/dL vs. 10.4±0.3 mg/dL, p < 0.05) and magnesium (2.02±0.27 mg/dL vs. 2.2±0.14 mg/dL, p < 0.05) levels were noted as being low in infants with marked malnutrition. No difference was found in LC-PUFA levels between healthy and malnourished infants. Thalamic choline/creatine levels were significantly high in infants with malnutrition (1.33±0.22 vs. 1.18±0.22, p < 0.05). Total neurocognitive development in infants was positively correlated with serum calcium levels (p < 0.05, r=0.381). CONCLUSION: Calcium supplementation may improve neurocognitive development in malnourished infants.


Subject(s)
Brain , Calcium , Cell Count , Cell Movement , Child , Cognition , Fatty Acids, Unsaturated , Humans , Infant , Magnesium , Magnetic Resonance Spectroscopy , Malnutrition , Mass Screening , Micronutrients , Spectrum Analysis , Synaptic Transmission
14.
Neuroscience Bulletin ; (6): 301-314, 2019.
Article in English | WPRIM | ID: wpr-775476

ABSTRACT

Neuropathic pain is a chronic debilitating symptom characterized by spontaneous pain and mechanical allodynia. It occurs in distinct forms, including brush-evoked dynamic and filament-evoked punctate mechanical allodynia. Potassium channel 2.1 (Kir2.1), which exhibits strong inward rectification, is and regulates the activity of lamina I projection neurons. However, the relationship between Kir2.1 channels and mechanical allodynia is still unclear. In this study, we first found that pretreatment with ML133, a selective Kir2.1 inhibitor, by intrathecal administration, preferentially inhibited dynamic, but not punctate, allodynia in mice with spared nerve injury (SNI). Intrathecal injection of low doses of strychnine, a glycine receptor inhibitor, selectively induced dynamic, but not punctate allodynia, not only in naïve but also in ML133-pretreated mice. In contrast, bicuculline, a GABA receptor antagonist, induced only punctate, but not dynamic, allodynia. These results indicated the involvement of glycinergic transmission in the development of dynamic allodynia. We further found that SNI significantly suppressed the frequency, but not the amplitude, of the glycinergic spontaneous inhibitory postsynaptic currents (gly-sIPSCs) in neurons on the lamina II-III border of the spinal dorsal horn, and pretreatment with ML133 prevented the SNI-induced gly-sIPSC reduction. Furthermore, 5 days after SNI, ML133, either by intrathecal administration or acute bath perfusion, and strychnine sensitively reversed the SNI-induced dynamic, but not punctate, allodynia and the gly-sIPSC reduction in lamina IIi neurons, respectively. In conclusion, our results suggest that blockade of Kir2.1 channels in the spinal dorsal horn selectively inhibits dynamic, but not punctate, mechanical allodynia by enhancing glycinergic inhibitory transmission.


Subject(s)
Animals , Bicuculline , Pharmacology , Disease Models, Animal , Glycine , Metabolism , Hyperalgesia , Drug Therapy , Metabolism , Imidazoles , Pharmacology , Inhibitory Postsynaptic Potentials , Physiology , Male , Mice, Inbred C57BL , Neurons , Metabolism , Neurotransmitter Agents , Pharmacology , Peripheral Nerve Injuries , Drug Therapy , Metabolism , Phenanthrolines , Pharmacology , Potassium Channels, Inwardly Rectifying , Metabolism , Receptors, GABA-A , Metabolism , Receptors, Glycine , Metabolism , Strychnine , Pharmacology , Synaptic Transmission , Physiology , Tissue Culture Techniques , Touch
15.
Acta méd. (Porto Alegre) ; 39(1): 23-35, 2018.
Article in Portuguese | LILACS | ID: biblio-910098

ABSTRACT

Objetivos: Descrever, de forma resumida, as principais descobertas históricas referentes a aquisiçao dos conhecimentos acerca da neurotransmissão. Métodos: Foi realizada busca de artigos nas bases de dados LILACS, Pubmed, Medline, Up to date e Medscape, durante o período de janeiro a maio de 2018, com o critério de atualidade como publicado nos últimos cinco anos, bem como foi revisada literatura consagrada em Neurologia. Resultados: A história da neurotransmissão evoluiu gradualmente a partir do século XIX e ao longo dos anos através dos esforços meticulosos de um grande número personalidades históricas. Seu desenvolvimento foi de extrema relevância para a evolução médica nos campos da neurofisiologia, da neurologia, da neuropsiquiatria, da psicofarmacologia e da anestesia. Conclusões: Encontramos marcos fundamentais na evolução da história da neurotransmissão e das estruturas da arquitetura neuronal nela implicadas, desde a descoberta do neurônio, do impulso elétrico, dos neurotransmissores e de mecanismos de transdução celular, bem como os cientistas que realizaram essas descobertas, elementos importantes para a compreensão da neurobiologia do cérebro.


Objectives: To describe, in a summary form, the main historical findings regarding the acquisition of knowledge about neurotransmission. Methods: A search of articles in the LILACS, Pubmed, Medline, Up to date and Medscape databases was performed, with the current criterion as published in the last five years, as well as literature review consecrated in Neurology. Results: The history of neurotransmission evolved gradually from the nineteenth century and over the years through the meticulous efforts of a large number of historical personalities, Its development was extremely relevant to medical developments in the fields of neurophysiology, neurology, neuropsychiatry, psychopharmacology and anesthesia. Conclusions: We found key milestones in the evolution of the history of neurotransmission and the neuronal architecture structures involved, from the discovery of the neuron, the electrical impulse, neurotransmitters and cellular transduction mechanisms, as well as the scientists who made these discoveries, important elements to understand the neurobiology of the brain.


Subject(s)
Synaptic Transmission , Acetylcholine , Neurons , Synapses
16.
Biol. Res ; 51: 35, 2018. graf
Article in English | LILACS | ID: biblio-983939

ABSTRACT

BACKGROUND: The previous studies have demonstrated the reduction of thiamine diphosphate is specific to Alzheimer's disease (AD) and causal factor of brain glucose hypometabolism, which is considered as a neurodegenerative index of AD and closely correlates with the degree of cognitive impairment. The reduction of thiamine diphosphate may contribute to the dysfunction of synapses and neural circuits, finally leading to cognitive decline. RESULTS: To demonstrate this hypothesis, we established abnormalities in the glucose metabolism utilizing thiamine deficiency in vitro and in vivo, and we found dramatically reduced dendrite spine density. We further detected lowered excitatory neurotransmission and impaired hippocampal long-term potentiation, which are induced by TPK RNAi in vitro. Importantly, via treatment with benfotiamine, Aß induced spines density decrease was considerably ameliorated. CONCLUSIONS: These results revealed that thiamine deficiency contributed to synaptic dysfunction which strongly related to AD pathogenesis. Our results provide new insights into pathogenesis of synaptic and neuronal dysfunction in AD.


Subject(s)
Animals , Male , Synapses/physiology , Thiamine Deficiency/complications , Thiamine Deficiency/metabolism , Thiamine Pyrophosphate/deficiency , Alzheimer Disease/etiology , Alzheimer Disease/metabolism , Neurons/physiology , Thiamine Deficiency/physiopathology , Thiamine Pyrophosphate/metabolism , Random Allocation , Blotting, Western , Amyloid beta-Peptides/metabolism , Rats, Sprague-Dawley , Diphosphotransferases/metabolism , Synaptic Transmission/physiology , Dendritic Spines/metabolism , Alzheimer Disease/physiopathology , Real-Time Polymerase Chain Reaction , Glucose/metabolism , Hippocampus/physiopathology , Hippocampus/metabolism , Mice, Inbred C57BL
17.
Neuroscience Bulletin ; (6): 156-164, 2018.
Article in English | WPRIM | ID: wpr-777082

ABSTRACT

Peripheral itch stimuli are transmitted by sensory neurons to the spinal cord dorsal horn, which then transmits the information to the brain. The molecular and cellular mechanisms within the dorsal horn for itch transmission have only been investigated and identified during the past ten years. This review covers the progress that has been made in identifying the peptide families in sensory neurons and the receptor families in dorsal horn neurons as putative itch transmitters, with a focus on gastrin-releasing peptide (GRP)-GRP receptor signaling. Also discussed are the signaling mechanisms, including opioids, by which various types of itch are transmitted and modulated, as well as the many conflicting results arising from recent studies.


Subject(s)
Action Potentials , Analgesics, Opioid , Pharmacology , Animals , Humans , Pruritus , Metabolism , Pathology , Sensory Receptor Cells , Metabolism , Spinal Cord , Pathology , Synaptic Transmission , Physiology
18.
Neuroscience Bulletin ; (6): 186-193, 2018.
Article in English | WPRIM | ID: wpr-777076

ABSTRACT

In 1905, Henry Head first suggested that transmission of pain-related protopathic information can be negatively modulated by inputs from afferents sensing innocuous touch and temperature. In 1965, Melzak and Wall proposed a more concrete gate control theory of pain that highlights the interaction between unmyelinated C fibers and myelinated A fibers in pain transmission. Here we review the current understanding of the spinal microcircuits transmitting and gating mechanical pain or itch. We also discuss how disruption of the gate control could cause pain or itch evoked by innocuous mechanical stimuli, a hallmark symptom for many chronic pain or itch patients.


Subject(s)
Animals , Humans , Nerve Net , Pathology , Pain , Pathology , Pruritus , Pathology , Spinal Cord , Pathology , Synaptic Transmission , Physiology
19.
Article in Korean | WPRIM | ID: wpr-740082

ABSTRACT

Reactive oxygen species (ROS) and nitrogen species (RNS) are involved in cellular signaling processes as a cause of oxidative stress. According to recent studies, ROS and RNS are important signaling molecules involved in pain transmission through spinal mechanisms. In this study, a patch clamp recording was used in spinal slices of rats to investigate the action mechanisms of O₂˙⁻ and NO on the excitability of substantia gelatinosa (SG) neuron. The application of xanthine and xanthine oxidase (X/XO) compound, a ROS donor, induced inward currents and increased the frequency of spontaneous excitatory postsynaptic currents (sEPSC) in slice preparation. The application of S-nitroso-N-acetyl-DLpenicillamine (SNAP), a RNS donor, also induced inward currents and increased the frequency of sEPSC. In a single cell preparation, X/XO and SNAP had no effect on the inward currents, revealing the involvement of presynaptic action. X/XO and SNAP induced a membrane depolarization in current clamp conditions which was significantly decreased by the addition of thapsigargin to an external calcium free solution for blocking synaptic transmission. Furthermore, X/XO and SNAP increased the frequency of action potentials evoked by depolarizing current pulses, suggesting the involvement of postsynaptic action. According to these results, it was estblished that elevated ROS and RNS in the spinal cord can sensitize the dorsal horn neurons via pre- and postsynaptic mechanisms. Therefore, ROS and RNS play similar roles in the regulation of the membrane excitability of SG neurons.


Subject(s)
Action Potentials , Animals , Calcium , Excitatory Postsynaptic Potentials , Humans , Membranes , Neurons , Nitric Oxide , Nitrogen , Oxidative Stress , Posterior Horn Cells , Rats , Reactive Oxygen Species , Spinal Cord , Substantia Gelatinosa , Superoxides , Synaptic Transmission , Thapsigargin , Tissue Donors , Xanthine , Xanthine Oxidase
20.
Article in English | WPRIM | ID: wpr-714653

ABSTRACT

OBJECTIVE: Propofol is an intravenously administered anesthetic that enhances γ-aminobutyric acid-mediated inhibition in the central nerve system. Other mechanisms may also be involved in general anesthesia. Propofol has been implicated in movement disorders. The cerebellum is important for motor coordination and motor learning. The aim of the present study was to investigate the propofol effect on excitatory synaptic transmissions in cerebellar cortex. METHODS: Excitatory postsynaptic currents by parallel fiber stimulation and complex spikes by climbing fiber stimulation were monitored in Purkinje cells of Wister rat cerebellar slice using whole-cell patch-clamp techniques. RESULTS: Decay time, rise time and amplitude of excitatory postsynaptic currents at parallel fiber Purkinje cell synapses and area of complex spikes at climbing fiber Purkinje cell synapses were significantly increased by propofol administration. CONCLUSION: The detected changes of glutamatergic synaptic transmission in cerebellar Purkinje cell, which determine cerebellar motor output, could explain cerebellar mechanism of motor deficits induced by propofol.


Subject(s)
Anesthesia, General , Anesthetics , Animals , Cerebellar Cortex , Cerebellum , Excitatory Postsynaptic Potentials , Learning , Movement Disorders , Patch-Clamp Techniques , Propofol , Purkinje Cells , Rats , Synapses , Synaptic Transmission
SELECTION OF CITATIONS
SEARCH DETAIL