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1.
Artigo em Inglês | MEDLINE | ID: mdl-38789642

RESUMO

Preclinical research with rodents suggests that the L-type calcium channel blocker isradipine can enhance long-term extinction of conditioned place preference for addictive substances when it is administered in conjunction with extinction training. Although isradipine alone, which is FDA-approved for hypertension, has not shown a direct effect on craving in human drug users, its potential to augment behavioral treatments designed to reduce craving remains unknown. We conducted a triple-blind, randomized placebo-controlled pilot clinical trial of isradipine combined with a novel virtual reality cue exposure therapy (VR-CET) approach with multimodal cues that targeted craving. After 24 hours of abstinence, 78 adults with an ongoing history of daily cigarette use received isradipine (n = 40) or placebo (n = 38) and reported craving levels after each of 10 trials of VR-CET. Consistent with pre-registered hypotheses, the isradipine group had significantly lower mean craving across cue exposure trials at the medication-free 24-hour follow-up (d = -0.42, p = 0.046). There were no serious adverse events; however, side effects such as headache and dizziness occurred more frequently in the isradipine group. The findings of the current study support follow-up clinical trials that specifically test the efficacy of isradipine-augmented VR-CET for reducing smoking relapse rates after an initial quit attempt. clinicaltrials.gov: NCT03083353.

2.
Sci Rep ; 13(1): 4914, 2023 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-36966212

RESUMO

Maize is the world's most produced cereal crop, and the selection of maize cultivars with a high stem elastic modulus is an effective method to prevent cereal crop lodging. We developed an ultra-compact sensor array inspired by earthquake engineering and proposed a method for the high-throughput evaluation of the elastic modulus of maize cultivars. A natural vibration analysis based on the obtained Young's modulus using finite element analysis (FEA) was performed and compared with the experimental results, which showed that the estimated Young's modulus is representative of the individual Young's modulus. FEA also showed the hotspot where the stalk was most deformed when the corn was vibrated by wind. The six tested cultivars were divided into two phenotypic groups based on the position and number of hotspots. In this study, we proposed a non-destructive high-throughput phenotyping technique for estimating the modulus of elasticity of maize stalks and successfully visualized which parts of the stalks should be improved for specific cultivars to prevent lodging.


Assuntos
Zea mays , Módulo de Elasticidade , Elasticidade , Análise de Elementos Finitos
3.
Exp Clin Psychopharmacol ; 31(2): 507-522, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36595455

RESUMO

Given the personal and public health burden of addictive disorders, innovative approaches to treatment are sorely needed. This systematic review examined the use of the pharmacological agent isradipine in the context of potential applications for addiction treatment. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guided a comprehensive search of PubMed, Cochrane Library, and PsycINFO between the years 1985 to July 2022. Studies were included if isradipine was administered to adults with a current Diagnostic and Statistical Manual of Mental Disorders-5th edition diagnosis of a substance use disorder and/or to healthy volunteers alone and in conjunction with a substance (i.e, cocaine, methamphetamine, alcohol). A total of 16 studies with 252 participants were included in this review. Substantial variability was identified with study designs, isradipine dosages/dosing, and addictive substance of interest. Outcomes clustered in four categories: (a) cerebral blood flow (CBF), (b) hemodynamic effects, (c) subjective effects, and (d) cognitive effects. Isradipine was found to improve CBF in individuals with cocaine-induced hypoperfusion and in several studies was found to reduce parameters of blood pressure elevation after stimulant use. There were no significant findings on isradipine's effect on subjective reporting (i.e., craving, mood, drug affect) or cognition/attention. Given the limited number of studies identified in this review, there is insufficient data to draw clear conclusions. The direct effects of isradipine as a pharmacologic agent for addictive disorder treatment appear minimal, however, future work may benefit from examining the impact of isradipine as an augmentative agent within existing cue exposure paradigms for preventing cue-induced drug relapse. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Assuntos
Cocaína , Metanfetamina , Transtornos Relacionados ao Uso de Substâncias , Adulto , Humanos , Isradipino/farmacologia , Isradipino/uso terapêutico , Bloqueadores dos Canais de Cálcio/farmacologia , Bloqueadores dos Canais de Cálcio/uso terapêutico , Transtornos Relacionados ao Uso de Substâncias/tratamento farmacológico
4.
Neuropharmacology ; 221: 109290, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36241085

RESUMO

Over the past three decades, L-type Ca2+ channel (LTCC) blockers have been considered a potential therapeutic drug to alleviate the symptoms of drug addiction. This idea has been supported, in part, by 1) expression of LTCCs in the brain dopaminergic circuits that are thought to play critical roles in the development and expression of addictive behaviors and 2) common usage of LTCC blockers in treating hypertension, which may enable off-label use of these drugs with good brain penetration as therapeutics for brain disorders. Addiction can be viewed as a maladaptive form of learning where powerful memories of drug-associated stimuli and actions drive compulsive drug intake. Largely under this framework, we will focus on the dopaminergic system that is thought be critically involved in drug-associated learning and memory and provide a brief overview of the past and recent studies testing the therapeutic potential of LTCC blockers for addictive disorders in animal models and humans and offer a future perspective on the use of LTCC blockers in drug addiction and, possibly, addiction to other non-drug rewards (e.g., gambling, eating, shopping). Interested readers can refer to other related articles in this issue and a comprehensive review available elsewhere (Little, 2021) to gain further insights into the roles of LTCCs in drug addiction and withdrawal symptoms associated with dependence. This article is part of the Special Issue on 'L-type calcium channel mechanisms in neuropsychiatric disorders'.


Assuntos
Comportamento Aditivo , Transtornos Relacionados ao Uso de Substâncias , Animais , Humanos , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo L/metabolismo , Comportamento Aditivo/tratamento farmacológico , Comportamento Aditivo/psicologia , Recompensa , Dopamina/metabolismo , Transtornos Relacionados ao Uso de Substâncias/psicologia
5.
Orthop J Sports Med ; 10(3): 23259671221079349, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35295553

RESUMO

Background: Articular cartilage repair remains challenging despite the availability of techniques, including autologous chondrocyte implantation (ACI) for repairing large cartilage defects. Platelet-rich plasma (PRP) therapy, a novel therapy focused on chondrocyte regeneration, needs to be investigated regarding its potential to improve the outcomes of ACI. Purpose: To examine the effect of PRP therapy on the outcomes of cartilage repair using the ACI procedure in a rabbit model of knee joint cartilage damage. Study Design: Controlled laboratory study. Methods: A total of 30 knees in 15 Japanese White rabbits (joint cartilage damage model) were divided into nontreatment (n = 7), PRP (n = 8), ACI (n = 7), and combined ACI and PRP (n = 8) groups. At 4 weeks and 12 weeks postoperatively, histological and visual examination of the surgical site was performed, and the regenerated cartilage and calcified bone areas were measured by imaging the specimens. Results: Pretransplantation evaluation in the cultured cartilage showed the histological properties of hyaline cartilage. At 4 weeks postoperatively, the regenerated cartilage area at the surgical site showed a larger safranin O-positive area in the ACI group (2.73 ± 4.46 mm2) than in the combined ACI and PRP group (1.71 ± 2.04 mm2). Calcified bone formation in the ACI group was relatively lower than that in the other groups. Cartilage repair failure occurred in all groups at 12 weeks postoperatively. Conclusion: The authors found no positive effects of PRP on the outcomes of ACI in a rabbit model. There was a smaller safranin O-positive region with the addition of PRP to ACI compared with ACI alone. In the subchondral bone, bone formation might have been promoted by PRP. Clinical Relevance: Administering PRP at the time of ACI may not have a positive effect and may have deleterious effects on cartilage engraftment and regeneration.

6.
Cell ; 181(6): 1205-1206, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32470394

RESUMO

Biasing G protein-coupled receptor signaling with ligands that promote select pathways is emerging as a powerful approach for therapeutic drug discovery. In this issue of Cell, Slosky et al. report a ß-arrestin-biased neurotensin receptor ligand that may curtail drug abuse without the side effects induced by G protein signaling.


Assuntos
Comportamento Aditivo , Receptores de Neurotensina , Ligantes , Neurotensina , Receptores de Neurotensina/metabolismo , beta-Arrestina 1 , beta-Arrestinas
7.
Contemp Clin Trials ; 94: 106013, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32335287

RESUMO

Cigarette smoking remains a leading cause of preventable death in the United States, contributing to over 480,000 deaths each year. Although significant strides have been made in the development of effective smoking cessation treatments, most established interventions are associated with high relapse rates. One avenue for increasing the effectiveness of smoking cessation interventions is to design focused, efficient, and rigorous experiments testing engagement of well-defined mechanistic targets. Toward this aim, the current protocol will apply a pharmacologic augmentation strategy informed by basic research in animal models of addiction. Our goal is to evaluate the enhancing effect of isradipine, an FDA-approved calcium channel blocker, on the extinction of craving-a key mechanism of drug relapse after periods of abstinence. To activate craving robustly in human participants, we will use multimodal smoking cues including novel 360° video environments developed for this project and delivered through consumer virtual reality headsets. Adult smokers will take either isradipine or placebo and complete the cue exposure protocol in a double-blind randomized control trial. In order to test the hypothesis that isradipine will enhance retention of craving extinction, participants will repeat cue exposure 24 h later without the administration of isradipine or placebo. The study will be implemented in a primary care setting where adult smokers receive healthcare, and smoking behavior will be tracked throughout the trial with ecological momentary assessment.


Assuntos
Abandono do Hábito de Fumar , Realidade Virtual , Sinais (Psicologia) , Atenção à Saúde , Humanos , Isradipino , Ensaios Clínicos Controlados Aleatórios como Assunto
8.
J Neurosci ; 39(6): 1030-1043, 2019 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-30530860

RESUMO

The central amygdala (CeA) is important for fear responses to discrete cues. Recent findings indicate that the CeA also contributes to states of sustained apprehension that characterize anxiety, although little is known about the neural circuitry involved. The stress neuropeptide corticotropin releasing factor (CRF) is anxiogenic and is produced by subpopulations of neurons in the lateral CeA and the dorsolateral bed nucleus of the stria terminalis (dlBST). Here we investigated the function of these CRF neurons in stress-induced anxiety using chemogenetics in male rats that express Cre recombinase from a Crh promoter. Anxiety-like behavior was mediated by CRF projections from the CeA to the dlBST and depended on activation of CRF1 receptors and CRF neurons within the dlBST. Our findings identify a CRFCeA→CRFdlBST circuit for generating anxiety-like behavior and provide mechanistic support for recent human and primate data suggesting that the CeA and BST act together to generate states of anxiety.SIGNIFICANCE STATEMENT Anxiety is a negative emotional state critical to survival, but persistent, exaggerated apprehension causes substantial morbidity. Identifying brain regions and neurotransmitter systems that drive anxiety can help in developing effective treatment. Much evidence in rodents indicates that neurons in the bed nucleus of the stria terminalis (BST) generate anxiety-like behaviors, but more recent findings also implicate neurons of the CeA. The neuronal subpopulations and circuitry that generate anxiety are currently subjects of intense investigation. Here we show that CeA neurons that release the stress neuropeptide corticotropin-releasing factor (CRF) drive anxiety-like behaviors in rats via a pathway to dorsal BST that activates local BST CRF neurons. Thus, our findings identify a CeA→BST CRF neuropeptide circuit that generates anxiety-like behavior.


Assuntos
Tonsila do Cerebelo/fisiopatologia , Ansiedade/fisiopatologia , Hormônio Liberador da Corticotropina/genética , Rede Nervosa/fisiopatologia , Animais , Ansiedade/psicologia , Comportamento Animal , Corticosterona/metabolismo , Relações Interpessoais , Masculino , Neurônios/fisiologia , Ratos , Ratos Wistar , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Núcleos Septais/fisiopatologia , Estresse Psicológico/fisiopatologia , Estresse Psicológico/psicologia
9.
Cell Rep ; 22(10): 2756-2766, 2018 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-29514102

RESUMO

Stressful events rapidly trigger activity-dependent synaptic plasticity, driving the formation of aversive memories. However, it remains unclear how stressful experience affects plasticity mechanisms to regulate appetitive learning, such as intake of addictive drugs. Using rats, we show that corticotropin-releasing factor (CRF) and α1 adrenergic receptor (α1AR) signaling enhance the plasticity of NMDA-receptor-mediated glutamatergic transmission in ventral tegmental area (VTA) dopamine (DA) neurons through distinct effects on inositol 1,4,5-triphosphate (IP3)-dependent Ca2+ signaling. We find that CRF amplifies IP3-Ca2+ signaling induced by stimulation of α1ARs, revealing a cooperative mechanism that promotes glutamatergic plasticity. In line with this, acute social defeat stress engages similar cooperative CRF and α1AR signaling in the VTA to enhance learning of cocaine-paired cues. These data provide evidence that CRF and α1ARs act in concert to regulate IP3-Ca2+ signaling in the VTA and promote learning of drug-associated cues.


Assuntos
Sinalização do Cálcio , Cocaína/farmacologia , Hormônio Liberador da Corticotropina/metabolismo , N-Metilaspartato/metabolismo , Plasticidade Neuronal , Receptores Adrenérgicos alfa 1/metabolismo , Estresse Psicológico/metabolismo , Área Tegmentar Ventral/metabolismo , Animais , Condicionamento Psicológico , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Inositol 1,4,5-Trifosfato , Aprendizagem , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Norepinefrina/farmacologia , Fenilefrina/farmacologia , Ratos Sprague-Dawley
10.
Annu Rev Physiol ; 80: 219-241, 2018 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-28938084

RESUMO

In recent years, the population of neurons in the ventral tegmental area (VTA) and substantia nigra (SN) has been examined at multiple levels. The results indicate that the projections, neurochemistry, and receptor and ion channel expression in this cell population vary widely. This review centers on the intrinsic properties and synaptic regulation that control the activity of dopamine neurons. Although all dopamine neurons fire action potentials in a pacemaker pattern in the absence of synaptic input, the intrinsic properties that underlie this activity differ considerably. Likewise, the transition into a burst/pause pattern results from combinations of intrinsic ion conductances, inhibitory and excitatory synaptic inputs that differ among this cell population. Finally, synaptic plasticity is a key regulator of the rate and pattern of activity in different groups of dopamine neurons. Through these fundamental properties, the activity of dopamine neurons is regulated and underlies the wide-ranging functions that have been attributed to dopamine.


Assuntos
Neurônios Dopaminérgicos/fisiologia , Substância Negra/metabolismo , Área Tegmentar Ventral/metabolismo , Potenciais de Ação/fisiologia , Animais , Humanos , Plasticidade Neuronal/fisiologia , Substância Negra/citologia , Área Tegmentar Ventral/citologia
11.
PLoS One ; 12(8): e0183685, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28859110

RESUMO

Similar to drugs of abuse, the hedonic value of food is mediated, at least in part, by the mesostriatal dopamine (DA) system. Prolonged intake of either high calorie diets or drugs of abuse both lead to a blunting of the DA system. Most studies have focused on DAergic alterations in the striatum, but little is known about the effects of high calorie diets on ventral tegmental area (VTA) DA neurons. Since high calorie diets produce addictive-like DAergic adaptations, it is possible these diets may increase addiction susceptibility. However, high calorie diets consistently reduce psychostimulant intake and conditioned place preference in rodents. In contrast, high calorie diets can increase or decrease ethanol drinking, but it is not known how a junk food diet (cafeteria diet) affects ethanol drinking. In the current study, we administered a cafeteria diet consisting of bacon, potato chips, cheesecake, cookies, breakfast cereals, marshmallows, and chocolate candies to male Wistar rats for 3-4 weeks, producing an obese phenotype. Prior cafeteria diet feeding reduced homecage ethanol drinking over 2 weeks of testing, and transiently reduced sucrose and chow intake. Importantly, cafeteria diet had no effect on ethanol metabolism rate or blood ethanol concentrations following 2g/kg ethanol administration. In midbrain slices, we showed that cafeteria diet feeding enhances DA D2 receptor (D2R) autoinhibition in VTA DA neurons. These results show that junk food diet-induced obesity reduces ethanol drinking, and suggest that increased D2R autoinhibition in the VTA may contribute to deficits in DAergic signaling and reward hypofunction observed with obesity.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Neurônios Dopaminérgicos/metabolismo , Obesidade/metabolismo , Receptores de Dopamina D2/metabolismo , Consumo de Bebidas Alcoólicas/metabolismo , Animais , Dopamina/metabolismo , Neurônios Dopaminérgicos/patologia , Etanol/efeitos adversos , Humanos , Mesencéfalo/metabolismo , Obesidade/etiologia , Obesidade/patologia , Ratos , Área Tegmentar Ventral/metabolismo , Área Tegmentar Ventral/patologia
12.
Alcohol ; 60: 95-101, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28433417

RESUMO

There is growing evidence that small-molecule inhibitors of epigenetic modulators, such as histone deacetylases (HDAC) and DNA methyltransferases (DNMT), can reduce voluntary ethanol consumption in animal models, but molecular and cellular processes underlying this behavioral effect are poorly understood. We used C57BL/6J male mice to investigate the effects of two FDA-approved drugs, decitabine (a DNMT inhibitor) and SAHA (an HDAC inhibitor), on ethanol consumption using two tests: binge-like drinking in the dark (DID) and chronic intermittent every other day (EOD) drinking. Decitabine but not SAHA reduced ethanol consumption in both tests. We further investigated decitabine's effects on the brain's reward pathway by gene expression profiling in the ventral tegmental area (VTA), using RNA sequencing and electrophysiological recordings from VTA dopaminergic neurons. Decitabine-induced decreases in EOD drinking were associated with global changes in gene expression, implicating regulation of cerebral blood flow, extracellular matrix organization, and neuroimmune functions in decitabine actions. In addition, an in vivo administration of decitabine shortened ethanol-induced excitation of VTA dopaminergic neurons in vitro, suggesting that decitabine reduces ethanol drinking via changes in the reward pathway. Taken together, our data suggest a contribution of both neuronal and non-neuronal mechanisms in the VTA in the regulation of ethanol consumption. Decitabine and other epigenetic compounds have been approved for cancer treatment, and understanding their mechanisms of actions in the brain may assist in repurposing these drugs and developing novel therapies for central disorders, including drug addiction.


Assuntos
Consumo de Bebidas Alcoólicas/prevenção & controle , Azacitidina/análogos & derivados , Consumo Excessivo de Bebidas Alcoólicas/tratamento farmacológico , Inibidores Enzimáticos/farmacologia , Epigênese Genética/efeitos dos fármacos , Etanol/toxicidade , Área Tegmentar Ventral/efeitos dos fármacos , Potenciais de Ação , Consumo de Bebidas Alcoólicas/genética , Consumo de Bebidas Alcoólicas/metabolismo , Consumo de Bebidas Alcoólicas/psicologia , Animais , Azacitidina/farmacologia , Comportamento Animal/efeitos dos fármacos , Consumo Excessivo de Bebidas Alcoólicas/genética , Consumo Excessivo de Bebidas Alcoólicas/metabolismo , Consumo Excessivo de Bebidas Alcoólicas/psicologia , Metilases de Modificação do DNA/antagonistas & inibidores , Metilases de Modificação do DNA/metabolismo , Decitabina , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Humanos , Ácidos Hidroxâmicos/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Recompensa , Fatores de Tempo , Transcriptoma/efeitos dos fármacos , Área Tegmentar Ventral/metabolismo , Área Tegmentar Ventral/fisiopatologia , Vorinostat
13.
Elife ; 52016 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-27374604

RESUMO

Enduring memories of sensory cues associated with drug intake drive addiction. It is well known that stressful experiences increase addiction vulnerability. However, it is not clear how repeated stress promotes learning of cue-drug associations, as repeated stress generally impairs learning and memory processes unrelated to stressful experiences. Here, we show that repeated social defeat stress in rats causes persistent enhancement of long-term potentiation (LTP) of NMDA receptor-mediated glutamatergic transmission in the ventral tegmental area (VTA). Protein kinase A-dependent increase in the potency of inositol 1,4,5-triphosphate-induced Ca(2+) signaling underlies LTP facilitation. Notably, defeated rats display enhanced learning of contextual cues paired with cocaine experience assessed using a conditioned place preference (CPP) paradigm. Enhancement of LTP in the VTA and cocaine CPP in behaving rats both require glucocorticoid receptor activation during defeat episodes. These findings suggest that enhanced glutamatergic plasticity in the VTA may contribute, at least partially, to increased addiction vulnerability following repeated stressful experiences.


Assuntos
Plasticidade Neuronal , Receptores de Glutamato/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Comportamento Social , Estresse Psicológico/fisiopatologia , Área Tegmentar Ventral/fisiologia , Animais , Cocaína/administração & dosagem , Condicionamento Psicológico , Potenciação de Longa Duração , Ratos
14.
Cell Rep ; 15(3): 563-573, 2016 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-27068462

RESUMO

Dopamine action in the nucleus accumbens (NAc) is thought to drive appetitive behavior and Pavlovian reward learning. However, it remains controversial how dopamine achieves these behavioral effects by regulating medium spiny projection neurons (MSNs) of the NAc, especially on a behaviorally relevant timescale. Metabotropic glutamate receptor (mGluR)-induced Ca(2+) signaling dependent on the Ca(2+)- releasing messenger inositol 1,4,5-triphosphate (IP3) plays a critical role in controlling neuronal excitability and synaptic plasticity. Here, we show that transient dopamine application facilitates mGluR/IP3-induced Ca(2+) signals within a time window of ∼2-10 s in a subpopulation of MSNs in the NAc core. Dopamine facilitation of IP3-induced Ca(2+) signaling is mediated by D1 dopamine receptors. In dopamine-insensitive MSNs, activation of A2A adenosine receptors causes enhancement of IP3-evoked Ca(2+) signals, which is reversed by D2 dopamine receptor activation. These results show that dopamine differentially regulates Ca(2+) signaling on the order of seconds in two distinct MSN subpopulations.


Assuntos
Sinalização do Cálcio/efeitos dos fármacos , Dopamina/farmacologia , Núcleo Accumbens/metabolismo , Potenciais de Ação/efeitos dos fármacos , Animais , Cálcio/metabolismo , Inositol 1,4,5-Trifosfato/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Núcleo Accumbens/efeitos dos fármacos , Receptor A2A de Adenosina/metabolismo , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Fatores de Tempo
15.
J Seismol ; 20(1): 185-196, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28190962

RESUMO

Array methods like spatial auto-correlation (SPAC) method and the centerless circular array (CCA) method have provided a convenient means of inferring the phase velocity of surface waves. However, these methods are under the assumption of horizontally layered medium (lateral homogeneity) while the ground structure is actually likely to be inclined. Hence, it is expected to obtain more detailed information of ground structure such as inclination by making better use of the records. In recent years, the seismic interferometry theory has also been widely used to estimate ground structure. According to seismic interferometry theory, the cross correlation of motion between two sites is proportional to the imaginary part of the Green's function (IOG) between the two sites in diffuse wavefield. In this study, we can obtain the ratio of IOG between two sites by taking the ratio of power spectra between the same two sites. We propose this ratio as an indicator of the lateral heterogeneity between two sites. Through numerical simulation and a field test, we demonstrate that the significance of ratio of power spectra can be interpreted from the sight of ratio of IOG successfully.

16.
J Neurosci ; 33(6): 2697-708, 2013 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-23392696

RESUMO

The striatum is critically involved in the selection of appropriate actions in a constantly changing environment. The spiking activity of striatal spiny projection neurons (SPNs), driven by extrinsic glutamatergic inputs, is shaped by local GABAergic and cholinergic networks. For example, it is well established that different types of GABAergic interneurons, activated by extrinsic glutamatergic and local cholinergic inputs, mediate powerful feedforward inhibition of SPN activity. In this study, using mouse striatal slices, we show that glutamatergic and cholinergic inputs exert direct inhibitory regulation of SPN activity via activation of metabotropic glutamate receptors (mGluRs) and muscarinic acetylcholine receptors. While pressure ejection of the group I mGluR (mGluR1/5) agonist DHPG [(S)-3,5-dihydroxyphenylglycine] equally engages both mGluR1 and mGluR5 subtypes, the mGluR-dependent component of IPSCs elicited by intrastriatal electrical stimulation is almost exclusively mediated by the mGluR1 subtype. Ca(2+) release from intracellular stores specifically through inositol 1,4,5-triphospahte receptors (IP(3)Rs) and not ryanodine receptors (RyRs) mediates this form of inhibition by gating two types of Ca(2+)-activated K(+) channels (i.e., small-conductance SK channels and large-conductance BK channels). Conversely, spike-evoked Ca(2+) influx triggers Ca(2+) release solely through RyRs to generate SK-dependent slow afterhyperpolarizations, demonstrating functional segregation of IP(3)Rs and RyRs. Finally, IP(3)-induced Ca(2+) release is uniquely observed in SPNs and not in different types of interneurons in the striatum. These results demonstrate that IP(3)-mediated activation of SK and BK channels provides a robust mechanism for glutamatergic and cholinergic inputs to selectively suppress striatal output neuron activity.


Assuntos
Corpo Estriado/fisiologia , Receptores de Inositol 1,4,5-Trifosfato/fisiologia , Inibição Neural/fisiologia , Neurônios/fisiologia , Receptores de Glutamato Metabotrópico/fisiologia , Receptores Muscarínicos/fisiologia , Animais , Corpo Estriado/efeitos dos fármacos , Masculino , Metoxi-Hidroxifenilglicol/análogos & derivados , Metoxi-Hidroxifenilglicol/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Receptores de Glutamato Metabotrópico/agonistas
17.
Neuron ; 77(2): 335-45, 2013 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-23352169

RESUMO

Drug addiction is driven, in part, by powerful drug-related memories. Deficits in social life, particularly during adolescence, increase addiction vulnerability. Social isolation in rodents has been used extensively to model the effects of deficient social experience, yet its impact on learning and memory processes underlying addiction remains elusive. Here, we show that social isolation of rats during a critical period of adolescence (postnatal days 21-42) enhances long-term potentiation of NMDA receptor (NMDAR)-mediated glutamatergic transmission in the ventral tegmental area (VTA). This enhancement, which is caused by an increase in metabotropic glutamate receptor-dependent Ca(2+) signaling, cannot be reversed by subsequent resocialization. Notably, memories of amphetamine- and ethanol-paired contextual stimuli are acquired faster and, once acquired, amphetamine-associated contextual memory is more resistant to extinction in socially isolated rats. We propose that NMDAR plasticity in the VTA may represent a neural substrate by which early life deficits in social experience increase addiction vulnerability.


Assuntos
Dextroanfetamina/farmacologia , Aprendizagem/fisiologia , Plasticidade Neuronal/fisiologia , Isolamento Social/psicologia , Sinapses/fisiologia , Área Tegmentar Ventral/fisiologia , Fatores Etários , Animais , Aprendizagem/efeitos dos fármacos , Masculino , Metoxi-Hidroxifenilglicol/análogos & derivados , Metoxi-Hidroxifenilglicol/farmacologia , Plasticidade Neuronal/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Sinapses/efeitos dos fármacos , Área Tegmentar Ventral/efeitos dos fármacos
18.
Neuropharmacology ; 67: 223-32, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23159531

RESUMO

Alcohol dependence/addiction is mediated by complex neural mechanisms that involve multiple brain circuits and neuroadaptive changes in a variety of neurotransmitter and neuropeptide systems. Although recent studies have provided substantial information on the neurobiological mechanisms that drive alcohol drinking behavior, significant challenges remain in understanding how alcohol-induced neuroadaptations occur and how different neurocircuits and pathways cross-talk. This review article highlights recent progress in understanding neural mechanisms of alcohol addiction from the perspectives of the development and maintenance of alcohol dependence. It provides insights on cross talks of different mechanisms and reviews the latest studies on metaplasticity, structural plasticity, interface of reward and stress pathways, and cross-talk of different neural signaling systems involved in binge-like drinking and alcohol dependence.


Assuntos
Alcoolismo/metabolismo , Comportamento Aditivo/metabolismo , Encéfalo/metabolismo , Alcoolismo/epidemiologia , Alcoolismo/psicologia , Animais , Comportamento Aditivo/epidemiologia , Comportamento Aditivo/psicologia , Consumo Excessivo de Bebidas Alcoólicas/epidemiologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Humanos , Rede Nervosa/metabolismo , Rede Nervosa/patologia , Rede Nervosa/fisiologia , Plasticidade Neuronal/fisiologia , Estresse Psicológico/epidemiologia , Estresse Psicológico/fisiopatologia , Estresse Psicológico/psicologia
19.
J Neurophysiol ; 108(3): 771-81, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22572945

RESUMO

During sensorimotor learning, tonically active neurons (TANs) in the striatum acquire bursts and pauses in their firing based on the salience of the stimulus. Striatal cholinergic interneurons display tonic intrinsic firing, even in the absence of synaptic input, that resembles TAN activity seen in vivo. However, whether there are other striatal neurons among the group identified as TANs is unknown. We used transgenic mice expressing green fluorescent protein under control of neuronal nitric oxide synthase or neuropeptide-Y promoters to aid in identifying low-threshold spike (LTS) interneurons in brain slices. We found that these neurons exhibit autonomous firing consisting of spontaneous transitions between regular, irregular, and burst firing, similar to cholinergic interneurons. As in cholinergic interneurons, these firing patterns arise from interactions between multiple intrinsic oscillatory mechanisms, but the mechanisms responsible differ. Both neurons maintain tonic firing because of persistent sodium currents, but the mechanisms of the subthreshold oscillations responsible for irregular firing are different. In LTS interneurons they rely on depolarization-activated noninactivating calcium currents, whereas those in cholinergic interneurons arise from a hyperpolarization-activated potassium conductance. Sustained membrane hyperpolarizations induce a bursting pattern in LTS interneurons, probably by recruiting a low-threshold, inactivating calcium conductance and by moving the membrane potential out of the activation range of the oscillatory mechanisms responsible for single spiking, in contrast to the bursting driven by noninactivating currents in cholinergic interneurons. The complex intrinsic firing patterns of LTS interneurons may subserve differential release of classic and peptide neurotransmitters as well as nitric oxide.


Assuntos
Interneurônios/fisiologia , Neostriado/fisiologia , Potenciais de Ação/fisiologia , Animais , Canais de Cálcio/fisiologia , Feminino , Masculino , Potenciais da Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Neurológicos , Canais de Potássio/fisiologia , Canais de Sódio/fisiologia
20.
Yonago Acta Med ; 55(1): 11-20, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24031135

RESUMO

The present study was performed by using selective inhibitors of caspase-8 and caspase-3 functioning upstream and downstream from mitochondria, respectively to determine whether mitochondria are involved in the mechanisms underlying production and externalization of oxidized phosphatidylserine (PSox) during Fas-mediated apoptosis. Treatment with anti-Fas antibody induced caspase-3 activation, chromatin condensation, release of cytochrome c (cyt c) from mitochondria into the cytosol as well as production of PSox and its exposure to the cell surface in Jurkat cells. Inhibition of caspase-8 by pretreatment with Z-IETD-FMK, a membrane permeable selective caspase-8 inhibitor reduced mitochondrial cyt c release, the amount of PSox not only within but also on the surface of Jurkat cells, caspase-3 activation, and apoptotic cell number after treatment with anti-Fas antibody. In contrast, Z-DEVD-FMK, a membrane permeable selective caspase-3 inhibitor was unable to inhibit cyt c release, and the amount of PSox both within and on the surface of the cells after anti-Fas antibody, although it suppressed caspase-3 activation and apoptosis. Thus, these results strongly suggest that mitochondria play an important role in production of PSox and subsequent its externalization during apoptosis.

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