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1.
J Neurosci ; 43(21): 3895-3908, 2023 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-37185097

RESUMO

Reward seeking requires the coordination of motor programs to achieve goals. Midbrain dopamine neurons are critical for reinforcement, and their activation is sufficient for learning about cues, actions, and outcomes. Here we examine in detail the mechanisms underlying the ability of ventral tegmental area (VTA) and substantia nigra (SNc) dopamine neurons to support instrumental learning. By exploiting numerous behavioral tasks in combination with time-limited optogenetic manipulations in male and female rats, we reveal that VTA and SNc dopamine neurons generate reinforcement through separable psychological processes. VTA dopamine neurons imbue actions and their associated cues with motivational value that allows flexible and persistent pursuit, whereas SNc dopamine neurons support time-limited, precise, action-specific learning that is nonscalable and inflexible. This architecture is reminiscent of actor-critic reinforcement learning models with VTA and SNc instructing the critic and actor, respectively. Our findings indicate that heterogeneous dopamine systems support unique forms of instrumental learning that ultimately result in disparate reward-seeking strategies.SIGNIFICANCE STATEMENT Dopamine neurons in the midbrain are essential for learning, motivation, and movement. Here we describe in detail the ability of VTA and SNc dopamine neurons to generate instrumental reinforcement, a process where an agent learns about actions they can emit to earn reward. While rats will avidly work and learn to respond for activation of VTA and SNc dopamine neurons, we find that only VTA dopamine neurons imbue actions and their associated cues with motivational value that spur continued pursuit of reward. Our data support a hypothesis that VTA and SNc dopamine neurons engage distinct psychological processes that have consequences for our understanding of these neurons in health and disease.


Assuntos
Neurônios Dopaminérgicos , Área Tegmentar Ventral , Ratos , Masculino , Feminino , Animais , Neurônios Dopaminérgicos/fisiologia , Área Tegmentar Ventral/fisiologia , Reforço Psicológico , Substância Negra/fisiologia , Recompensa
2.
Sensors (Basel) ; 24(14)2024 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-39066112

RESUMO

This paper predicts the network security posture of an ICS, focusing on the reliability of Industrial Control Systems (ICSs). Evidence reasoning (ER) and belief rule base (BRB) techniques are employed to establish an ICS network security posture prediction model, ensuring the secure operation and prediction of the ICS. This model first integrates various information from the ICS to determine its network security posture value. Subsequently, through ER iteration, information fusion occurs and serves as an input for the BRB prediction model, which necessitates initial parameter setting by relevant experts. External factors may influence the experts' predictions; therefore, this paper proposes the Projection Equalization Optimization (P-EO) algorithm. This optimization algorithm updates the initial parameters to enhance the prediction of the ICS network security posture through the model. Finally, industrial datasets are used as experimental data to improve the credibility of the prediction experiments and validate the model's predictive performance in the ICS. Compared with other methods, this paper's prediction model demonstrates a superior prediction accuracy. By further comparing with other algorithms, this paper has a certain advantage when using less historical data to make predictions.

3.
Int J Mol Sci ; 25(6)2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38542425

RESUMO

Brain-stimulation reward, also known as intracranial self-stimulation (ICSS), is a commonly used procedure for studying brain reward function and drug reward. In electrical ICSS (eICSS), an electrode is surgically implanted into the medial forebrain bundle (MFB) in the lateral hypothalamus or the ventral tegmental area (VTA) in the midbrain. Operant lever responding leads to the delivery of electrical pulse stimulation. The alteration in the stimulation frequency-lever response curve is used to evaluate the impact of pharmacological agents on brain reward function. If a test drug induces a leftward or upward shift in the eICSS response curve, it implies a reward-enhancing or abuse-like effect. Conversely, if a drug causes a rightward or downward shift in the functional response curve, it suggests a reward-attenuating or aversive effect. A significant drawback of eICSS is the lack of cellular selectivity in understanding the neural substrates underlying this behavior. Excitingly, recent advancements in optical ICSS (oICSS) have facilitated the development of at least three cell type-specific oICSS models-dopamine-, glutamate-, and GABA-dependent oICSS. In these new models, a comparable stimulation frequency-lever response curve has been established and employed to study the substrate-specific mechanisms underlying brain reward function and a drug's rewarding versus aversive effects. In this review article, we summarize recent progress in this exciting research area. The findings in oICSS have not only increased our understanding of the neural mechanisms underlying drug reward and addiction but have also introduced a novel behavioral model in preclinical medication development for treating substance use disorders.


Assuntos
Roedores , Autoestimulação , Animais , Recompensa , Mesencéfalo , Feixe Prosencefálico Mediano , Estimulação Elétrica
4.
Brain Behav Immun ; 107: 47-52, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36174884

RESUMO

P2X7 receptors are dysregulated during psychostimulant exposure. Furthermore, P2X7 receptors enhance endogenous systems (e.g., cytokines, dopamine, and glutamate) that facilitate psychostimulant addiction. Therefore, using mouse locomotor, conditioned place preference (CPP), and intracranial self-stimulation (ICSS) assays, we tested the hypothesis that methamphetamine (METH) reward and acute locomotor activation requires P2X7 receptor activity. We also investigated effects of P2X7 blockade on METH-induced changes in cytokine levels in brain reward regions. A438079 (5, 10, 50 mg/kg), a P2X7 antagonist, did not affect spontaneous locomotor activity but reduced hyperlocomotion caused by acute METH (1 mg/kg) exposure. A438079 (10 mg/kg) also prevented expression of METH CPP without causing aversive or rewarding effects. For ICSS experiments, METH (1 mg/kg) facilitated brain reward function as interpreted from reductions in baseline threshold. In the presence of A438079 (50 mg/kg), METH-induced facilitation of ICSS was reduced. Repeated METH exposure (1 mg/kg × 7 d) caused enhancement of IL-17A levels in the prefrontal cortex (PFC) that was normalized by A438070 (10 mg/kg × 7 d). The present data suggest that P2X7 receptor activity contributes to rewarding and locomotor-stimulant effects of METH through a potential mechanism involving IL-17A, which has recently been implicated in anxiety.


Assuntos
Metanfetamina , Animais , Camundongos , Metanfetamina/farmacologia , Receptores Purinérgicos P2X7 , Antagonistas do Receptor Purinérgico P2X , Interleucina-17
5.
J Environ Manage ; 298: 113412, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34364247

RESUMO

Despite the multifarious benefits of improved cooking stoves (ICSs) over traditional biomass stoves, the ICSs adoption rate in rural Bangladesh remains nominal. This paper provides evidence that there is a growing demand for this environmentally friendly and less-hazardous stove. Using a discrete choice experiment (DCE) technique, we surveyed 259 sample households in the south-western region of Bangladesh. The results from the mixed logit model suggest that households are willing to pay (WTP) about $7 on average for a 'realistic' (i.e., one unit or 25 %) reduction in fuel consumption and smoke emission. Moreover, we found that a one-unit (33 %) reduction of cooking time and maintenance frequency increases households' WTP by about $3 and $5 respectively. Finally, this study underscores that extensive promotion, lower installation costs and higher social awareness about health risks and environmental degradation are likely to promote ICSs adoption.


Assuntos
Poluição do Ar em Ambientes Fechados , Utensílios Domésticos , Poluição do Ar em Ambientes Fechados/análise , Bangladesh , Culinária , Características da Família , Humanos , População Rural
6.
Int J Neuropsychopharmacol ; 22(11): 735-745, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31613314

RESUMO

BACKGROUND: New treatments for stress-related disorders including depression, anxiety, and substance use disorder are greatly needed. Kappa opioid receptors are expressed in the central nervous system, including areas implicated in analgesia and affective state. Although kappa opioid receptor agonists share the antinociceptive effects of mu opioid receptor agonists, they also tend to produce negative affective states. In contrast, selective kappa opioid receptor antagonists have antidepressant- and anxiolytic-like effects, stimulating interest in their therapeutic potential. The prototypical kappa opioid receptor antagonists (e.g., norBNI, JDTic) have an exceptionally long duration of action that complicates their use in humans, particularly in tests to establish safety. This study was designed to test dose- and time-course effects of novel kappa opioid receptor antagonists with the goal of identifying short-acting lead compounds for future medication development. METHODS: We screened 2 novel, highly selective kappa opioid receptor antagonists (CYM-52220 and CYM-52288) with oral efficacy in the warm water tail flick assay in rats to determine initial dose and time course effects. For comparison, we tested existing kappa opioid receptor antagonists JDTic and LY-2456302 (also known as CERC-501 or JNJ-67953964). RESULTS: In the tail flick assay, the rank order of duration of action for the antagonists was LY-2456302 < CYM-52288 < CYM-52220 << JDTic. Furthermore, LY-2456302 blocked the depressive (anhedonia-producing) effects of the kappa opioid receptor agonist U50,488 in the intracranial self-stimulation paradigm, albeit at a higher dose than that needed for analgesic blockade in the tail flick assay. CONCLUSIONS: These results suggest that structurally diverse kappa opioid receptor antagonists can have short-acting effects and that LY-2456302 reduces anhedonia as measured in the intracranial self-stimulation test.


Assuntos
(trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida/farmacologia , Analgésicos não Narcóticos/farmacologia , Ansiolíticos/farmacologia , Antidepressivos/farmacologia , Comportamento Animal/efeitos dos fármacos , Benzamidas/farmacologia , Antagonistas de Entorpecentes/farmacologia , Piperidinas/farmacologia , Pirrolidinas/farmacologia , Receptores Opioides kappa/antagonistas & inibidores , Tetra-Hidroisoquinolinas/farmacologia , (trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida/administração & dosagem , Analgésicos não Narcóticos/administração & dosagem , Animais , Ansiolíticos/administração & dosagem , Antidepressivos/administração & dosagem , Benzamidas/administração & dosagem , Desenvolvimento de Medicamentos , Avaliação Pré-Clínica de Medicamentos , Masculino , Antagonistas de Entorpecentes/administração & dosagem , Piperidinas/administração & dosagem , Pirrolidinas/administração & dosagem , Ratos , Ratos Sprague-Dawley , Receptores Opioides kappa/agonistas , Tetra-Hidroisoquinolinas/administração & dosagem
7.
J Neurosci ; 36(21): 5748-62, 2016 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-27225765

RESUMO

UNLABELLED: Dependence is a hallmark feature of opiate addiction and is defined by the emergence of somatic and affective withdrawal signs. The nucleus accumbens (NAc) integrates dopaminergic and glutamatergic inputs to mediate rewarding and aversive properties of opiates. Evidence suggests that AMPA glutamate-receptor-dependent synaptic plasticity within the NAc underlies aspects of addiction. However, the degree to which NAc AMPA receptors (AMPARs) contribute to somatic and affective signs of opiate withdrawal is not fully understood. Here, we show that microinjection of the AMPAR antagonist NBQX into the NAc shell of morphine-dependent rats prevented naloxone-induced conditioned place aversions and decreases in sensitivity to brain stimulation reward, but had no effect on somatic withdrawal signs. Using a protein cross-linking approach, we found that the surface/intracellular ratio of NAc GluA1, but not GluA2, increased with morphine treatment, suggesting postsynaptic insertion of GluA2-lacking AMPARs. Consistent with this, 1-naphthylacetyl spermine trihydrochloride (NASPM), an antagonist of GluA2-lacking AMPARs, attenuated naloxone-induced decreases in sensitivity to brain stimulation reward. Naloxone decreased the surface/intracellular ratio and synaptosomal membrane levels of NAc GluA1 in morphine-dependent rats, suggesting a compensatory removal of AMPARs from synaptic zones. Together, these findings indicate that chronic morphine increases synaptic availability of GluA1-containing AMPARs in the NAc, which is necessary for triggering negative-affective states in response to naloxone. This is broadly consistent with the hypothesis that activation of NAc neurons produces acute aversive states and raises the possibility that inhibiting AMPA transmission selectively in the NAc may have therapeutic value in the treatment of addiction. SIGNIFICANCE STATEMENT: Morphine dependence and withdrawal result in profound negative-affective states that play a major role in the maintenance of addiction. However, the underlying neurobiological mechanisms are not fully understood. We use a rat model of morphine dependence to show that GluA1 subunits of AMPA glutamate receptors in the nucleus accumbens (NAc), a brain region critical for modulating affective states, are necessary for aversive effects of morphine withdrawal. Using biochemical methods in NAc tissue, we show that morphine dependence increases cell surface expression of GluA1, suggesting that neurons in this area are primed for increased AMPA receptor activation upon withdrawal. This work is important because it suggests that targeting AMPA receptor trafficking and activation could provide novel targets for addiction treatment.


Assuntos
Transtornos do Humor/induzido quimicamente , Transtornos do Humor/metabolismo , Dependência de Morfina/metabolismo , Morfina/intoxicação , Núcleo Accumbens/metabolismo , Receptores de AMPA/metabolismo , Síndrome de Abstinência a Substâncias/metabolismo , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual
8.
Int J Neuropsychopharmacol ; 20(5): 403-409, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28031268

RESUMO

Background: Opioid and dopamine systems play crucial roles in reward. Similarities and differences in the neural mechanisms of reward that are mediated by these 2 systems have remained largely unknown. Thus, in the present study, we investigated the differences in reward function in both µ-opioid receptor knockout mice and dopamine transporter knockout mice, important molecules in the opioid and dopamine systems. Methods: Mice were implanted with electrodes into the right lateral hypothalamus (l hour). Mice were then trained to put their muzzle into the hole in the head-dipping chamber for intracranial electrical stimulation, and the influences of gene knockout were assessed. Results: Significant differences are observed between opioid and dopamine systems in reward function. µ-Opioid receptor knockout mice exhibited enhanced intracranial electrical stimulation, which induced dopamine release. They also exhibited greater motility under conditions of "despair" in both the tail suspension test and water wheel test. In contrast, dopamine transporter knockout mice maintained intracranial electrical stimulation responding even when more active efforts were required to obtain the reward. Conclusions: The absence of µ-opioid receptor or dopamine transporter did not lead to the absence of intracranial electrical stimulation responsiveness but rather differentially altered it. The present results in µ-opioid receptor knockout mice are consistent with the suppressive involvement of µ-opioid receptors in both positive incentive motivation associated with intracranial electrical stimulation and negative incentive motivation associated with depressive states. In contrast, the results in dopamine transporter knockout mice are consistent with the involvement of dopamine transporters in positive incentive motivation, especially its persistence. Differences in intracranial electrical stimulation in µ-opioid receptor and dopamine transporter knockout mice underscore the multidimensional nature of reward.


Assuntos
Analgésicos Opioides/metabolismo , Dopamina/metabolismo , Região Hipotalâmica Lateral/efeitos dos fármacos , Região Hipotalâmica Lateral/metabolismo , Receptores Opioides mu/deficiência , Animais , Biofísica , Proteínas da Membrana Plasmática de Transporte de Dopamina/deficiência , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Estimulação Elétrica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Motivação , Atividade Motora/efeitos dos fármacos , Receptores Opioides mu/genética , Recompensa , Autoadministração , Fatores de Tempo
9.
Neurobiol Learn Mem ; 127: 17-26, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26656274

RESUMO

Intracranial self-stimulation (ICSS) of the lateral hypothalamus (LH) is involved in the activation of neuroanatomical systems that are also associated with the processing of natural and other artificial rewarding stimuli. Specific components of this behavior (hedonic impact, learning, and motor behavior) may involve changes in different neurotransmitters, such as dopamine and opioids. In this study, quantitative autoradiography was used to examine changes in mu-opioid and D1/D2-dopamine receptor expression in various anatomical regions related to the motor and mesolimbic reward systems after intracranial self-stimulation of the LH. Results of the behavioral procedure and subsequent radiochemical assays show selective changes in D1 but not D2 or mu receptors in Accumbens-Shell, Ventral Pallidum, Caudate-Putamen, and Medial Globus Pallidus. These findings are discussed in relation to the different psychobiological components of the appetitive motivational system, identifying some dissociation among them, particularly with respect to the involvement of the D1-dopamine subsystem (but not D2 or mu receptors) in goal-directed behaviors.


Assuntos
Encéfalo/fisiologia , Região Hipotalâmica Lateral/fisiologia , Sistema Límbico/fisiologia , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Receptores Opioides mu/metabolismo , Animais , Autorradiografia , Encéfalo/metabolismo , Estimulação Elétrica , Sistema Límbico/metabolismo , Masculino , Ratos Wistar , Autoestimulação
10.
Addict Biol ; 20(2): 324-35, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24612112

RESUMO

Tobacco addiction is characterized by a lack of control over smoking and relapse after periods of abstinence. Smoking cessation leads to a dysphoric state that contributes to relapse to smoking. After the acute withdrawal phase, exposure to stressors increases the risk for relapse. Blockade of melanocortin 4 (MC4 ) receptors has anxiolytic and antidepressant-like effects in animal models. The aim of these studies was to investigate the role of MC4 receptors in the dysphoria associated with nicotine withdrawal and stress-induced reinstatement of nicotine seeking. To study stress-induced reinstatement, rats self-administered nicotine for 16 days and then nicotine seeking was extinguished by substituting saline for nicotine. Nicotine seeking was reinstated by intermittent footshock stress. The intracranial self-stimulation (ICSS) procedure was used to assess the negative mood state associated with nicotine withdrawal. Elevations in the ICSS thresholds are indicative of a dysphoric state. The selective MC4 receptor antagonists HS014 and HS024 prevented stress-induced reinstatement of extinguished nicotine seeking. Drug doses that prevented stress-induced relapse did not affect responding for food pellets, which indicates that the drugs did not induce sedation or motor impairments. In the ICSS experiments, the nicotinic acetylcholine receptor antagonist mecamylamine elevated the ICSS thresholds of the nicotine-dependent rats. Pre-treatment with HS014 or HS024 did not prevent the elevations in ICSS thresholds. These studies indicate that MC4 receptors play a critical role in stress-induced reinstatement of nicotine seeking, but these receptors may not play a role in the dysphoria associated with acute nicotine withdrawal.


Assuntos
Comportamento de Procura de Droga/fisiologia , Nicotina/administração & dosagem , Agonistas Nicotínicos/administração & dosagem , Receptor Tipo 4 de Melanocortina/metabolismo , Estresse Psicológico/metabolismo , Síndrome de Abstinência a Substâncias/metabolismo , Tabagismo/metabolismo , Animais , Comportamento de Procura de Droga/efeitos dos fármacos , Nicotina/efeitos adversos , Agonistas Nicotínicos/efeitos adversos , Peptídeos Cíclicos/farmacologia , Ratos , Receptor Tipo 4 de Melanocortina/antagonistas & inibidores , Recidiva , Síndrome de Abstinência a Substâncias/etiologia
11.
Int J Neuropsychopharmacol ; 18(1)2014 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-25522379

RESUMO

BACKGROUND: Use of synthetic cathinones, which are designer stimulants found in "bath salts," has increased dramatically in recent years. Following governmental bans of methylenedioxypyrovalerone, mephedrone, and methylone, a second generation of synthetic cathinones with unknown abuse liability has emerged as replacements. METHODS: Using a discrete trials current intensity threshold intracranial self-stimulation procedure, the present study assessed the effects of 2 common second-generation synthetic cathinones, α-pyrrolidinopentiophenone (0.1-5 mg/kg) and 4-methyl-N-ethcathinone (1-100 mg/kg) on brain reward function. Methamphetamine (0.1-3 mg/kg) was also tested for comparison purposes. RESULTS: Results revealed both α-pyrrolidinopentiophenone and 4-methyl-N-ethcathinone produced significant intracranial self-stimulation threshold reductions similar to that of methamphetamine. α-Pyrrolidinopentiophenone (1 mg/kg) produced a significant maximal reduction in intracranial self-stimulation thresholds (~19%) most similar to maximal reductions produced by methamphetamine (1 mg/kg, ~20%). Maximal reductions in intracranial self-stimulation thresholds produced by 4-methyl-N-ethcathinone were observed at 30 mg/kg (~15%) and were comparable with those observed with methamphetamine and α-pyrrolidinopentiophenone tested at the 0.3-mg/kg dose (~14%). Additional analysis of the ED50 values from log-transformed data revealed the rank order potency of these drugs as methamphetamine ≈ α-pyrrolidinopentiophenone>4-methyl-N-ethcathinone. CONCLUSIONS: These data suggest that the newer second-generation synthetic cathinones activate the brain reward circuitry and thus may possess a similar degree of abuse potential as prototypical illicit psychostimulants such as methamphetamine as well as the first generation synthetic cathinone methylenedioxypyrovalerone, as previously reported.


Assuntos
Estimulantes do Sistema Nervoso Central/farmacologia , Pentanonas/farmacologia , Pirrolidinas/farmacologia , Autoestimulação/efeitos dos fármacos , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/fisiologia , Estimulantes do Sistema Nervoso Central/química , Relação Dose-Resposta a Droga , Drogas Ilícitas , Modelos Lineares , Masculino , Metanfetamina/química , Metanfetamina/farmacologia , Estrutura Molecular , Pentanonas/química , Pirrolidinas/química , Ratos Sprague-Dawley
12.
Leadersh Health Serv (Bradf Engl) ; ahead-of-print(ahead-of-print)2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38345072

RESUMO

PURPOSE: Given the complex nature of integrated care systems (ICSs), the geographical spread and the large number of organisations involved in partnership delivery, the importance of leadership cannot be overstated. This paper aims to present novel findings from a rapid realist review of ICS leadership in England. The overall review question was: how does leadership in ICSs work, for whom and in what circumstances? DESIGN/METHODOLOGY/APPROACH: Development of initial programme theories and associated context-mechanism-outcome configurations (CMOCs) were supported by the theory-gleaning activities of a review of ICS strategies and guidance documents, a scoping review of the literature and interviews with key informants. A refined programme theory was then developed by testing these CMOCs against empirical data published in academic literature. Following screening and testing, six CMOCs were extracted from 18 documents. The study design, conduct and reporting were informed by the Realist And Metanarrative Evidence Syntheses: Evolving Standards (RAMESES) training materials (Wong et al., 2013). FINDINGS: The review informed four programme theories explaining that leadership in ICSs works when ICS leaders hold themselves and others to account for improving population health, a sense of purpose is fostered through a clear vision, partners across the system are engaged in problem ownership and relationships are built at all levels of the system. RESEARCH LIMITATIONS/IMPLICATIONS: Despite being a rigorous and comprehensive investigation, stakeholder input was limited to one ICS, potentially restricting insights from varied geographical contexts. In addition, the recent establishment of ICSs meant limited literature availability, with few empirical studies conducted. Although this emphasises the importance and originality of the research, this scarcity posed challenges in extracting and applying certain programme theory elements, particularly context. ORIGINALITY/VALUE: This review will be of relevance to academics and health-care leaders within ICSs in England, offering critical insights into ICS leadership, integrating diverse evidence to develop new evidence-based recommendations, filling a gap in the current literature and informing leadership practice and health-care systems.


Assuntos
Prestação Integrada de Cuidados de Saúde , Liderança , Humanos , Inglaterra
13.
Front Mol Neurosci ; 17: 1459098, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39346680

RESUMO

Background: Most smokers attempting to quit will quickly relapse to tobacco use even when treated with the most efficacious smoking cessation agents currently available. This highlights the need to develop effective new smoking cessation medications. Evidence suggests that positive allosteric modulators (PAM) and other enhancers of nicotinic acetylcholine receptor (nAChR) signaling could have therapeutic utility as smoking cessation agents. Methods: 3-[3-(3-pyridyl)-1,2,4-oxadiazol-5-yl]benzonitrile (NS9283) was used as a starting point for medical chemistry efforts to develop novel small molecule enhancers of α4ß2* nAChR stoichiometries containing a low-affinity agonist binding site at the interface of α4/α4 and α4/α5 subunits. Results: The NS9283 derivative SR9883 enhanced the effect of nicotine on α4ß2* nAChR stoichiometries containing low-affinity agonist binding sites, with EC50 values from 0.2-0.4 µM. SR9883 had no effect on α3ß2* or α3ß4* nAChRs. SR9883 was bioavailable after intravenous (1 mg kg-1) and oral (10-20 mg kg-1) administration and penetrated into the brain. When administered alone, SR9883 (5-10 mg kg-1) had no effect on locomotor activity or intracranial self-stimulation (ICSS) thresholds in mice. When co-administered with nicotine, SR9883 enhanced locomotor suppression and elevations of ICSS thresholds induced by nicotine. SR9883 (5 and 10 mg kg-1) decreased responding for intravenous nicotine infusions (0.03 mg kg-1 per infusion) but had no effect on responding for food rewards in rats. Conclusions: These data suggest that SR9883 is useful for investigating behavioral processes regulated by certain α4ß2* nAChR stoichiometries. SR9883 and related compounds with favorable drug-like physiochemical and pharmacological properties hold promise as novel treatments of tobacco use disorder.

14.
Neuropharmacology ; 240: 109732, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37774943

RESUMO

Prenatal opioid exposure is a major health concern in the United States, with the incidence of neonatal opioid withdrawal syndrome (NOWS) escalating in recent years. NOWS occurs upon cessation of in utero opioid exposure and is characterized by increased irritability, disrupted sleep patterns, high-pitched crying, and dysregulated feeding. The main pharmacological strategy for alleviating symptoms is treatment with replacement opioids. The neural mechanisms mediating NOWS and the long-term neurobehavioral effects are poorly understood. We used a third trimester-approximate model in which neonatal outbred pups (Carworth Farms White; CFW) were administered once-daily morphine (15 mg/kg, s.c.) from postnatal day (P) day 1 through P14 and were then assessed for behavioral and transcriptomic adaptations within the nucleus accumbens (NAc) on P15. We also investigated the long-term effects of perinatal morphine exposure on adult learning and reward sensitivity. We observed significant weight deficits, spontaneous thermal hyperalgesia, and altered ultrasonic vocalization (USV) profiles following repeated morphine and during spontaneous withdrawal. Transcriptome analysis of NAc from opioid-withdrawn P15 neonates via bulk mRNA sequencing identified an enrichment profile consistent with downregulation of myelin-associated transcripts. Despite the neonatal behavioral and molecular effects, there were no significant long-term effects of perinatal morphine exposure on adult spatial memory function in the Barnes Maze, emotional learning in fear conditioning, or in baseline or methamphetamine-potentiated reward sensitivity as measured via intracranial self-stimulation. Thus, the once daily third trimester-approximate exposure regimen, while inducing NOWS model traits and significant transcriptomic effects in neonates, had no significant long-term effects on adult behaviors.


Assuntos
Síndrome de Abstinência Neonatal , Transtornos Relacionados ao Uso de Opioides , Síndrome de Abstinência a Substâncias , Gravidez , Feminino , Animais , Camundongos , Analgésicos Opioides/farmacologia , Núcleo Accumbens , Bainha de Mielina , Síndrome de Abstinência a Substâncias/metabolismo , Entorpecentes/farmacologia , Morfina/farmacologia , Síndrome de Abstinência Neonatal/tratamento farmacológico , Síndrome de Abstinência Neonatal/epidemiologia , Síndrome de Abstinência Neonatal/etiologia , Expressão Gênica , Transtornos Relacionados ao Uso de Opioides/metabolismo
15.
Front Pharmacol ; 13: 834116, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35668949

RESUMO

Purpose: Inhaled Corticosteroids (ICSs) and oral Leukotriene Receptor Antagonists (LTRAs) are commonly prescribed asthma preventers, however, concerns have been raised as to whether montelukast (LTRA) is associated with an increase in occurrences of neuropsychiatric side effects in children. Our study was conducted to observe prescribing patterns of asthma preventers among paediatric patients specifically focusing on ICSs and LTRAs between Australia and South Korea to see intercountry differences in the use of these medicines. Materials and Methods: The Health Insurance Review and Assessment Paediatric Patients Sample dataset for South Korea and data provided by Services Australia were used in the study. Paediatric patients aged between 3 and 19 with more than one dispensing of an asthma preventer and at least one reliever between 1 Jan 2018 and 31 December 2018 were selected. Prevalence per 1,00,000 persons and standardised prevalence were estimated. Results: A total of 3,58,470 patients (2,04,270 from South Korea and 1,54,200 from Australia) were included in the study. A higher prevalence of ICS-based inhalers was seen in Australia with 80.1% compared to 13.5% in South Korea. In addition, Australia showed a stronger tendency of prescribing high dose ICS-based inhalers compared to South Korea with 22.9% vs. 4.9%. In contrast, use of LTRAs was more prevalent in South Korea with 57.6% while in Australia, montelukast was the only LTRA dispensed at a proportion of 18.9%. Moreover, 29.9% of xanthines which are orally available preventers, were prescribed more frequently in South Korea compared to Australia (0.1%). Conclusion: Australia showed a tendency of prescribing ICS-based preventers whereas South Korea exhibited a preference towards the oral LTRAs. Given the potential risk of neuropsychiatric side effects among paediatric patients with montelukast, reasons for the high use of montelukast in South Korea should be investigated further.

16.
Artigo em Inglês | MEDLINE | ID: mdl-35068929

RESUMO

Although pharmacological treatment of COPD is codified in different guidelines and strategy documents, there is abundant evidence of discrepancy between what they suggest and what health professionals prescribe, especially in low-risk groups where there is widespread overprescription of triple therapy. It is therefore necessary to clarify when the use of triple therapy is indicated in COPD patients and when it is preferable to maintain treatment with dual bronchodilation. In this article, we discuss our views based on our experience and what is reported in the literature and try to give answers to these two questions. The evidence generated by pivotal RCTs supports the use of triple therapy in patients who present for the first time and have severe airway obstruction, are symptomatic, have had frequent moderate or severe exacerbations in the previous year, and have peripheral eosinophilia. However, it is difficult to determine whether step-up is useful in all other cases because the available data are quite conflicting. It is likely that the inconsistency in the information generated by the various available studies may explain the prescribing behaviour of many physicians who do not adhere to recommendations of guidelines and strategies. However, it is necessary to establish whether and when the addition of an ICS to the LAMA/LABA combination is effective, to determine whether triple therapy can induce an additional clinical benefit over dual bronchodilation, irrespective of a preventive effect on COPD exacerbations, to establish its value, and to examine whether cost differences can support the use of triple therapy over combined LAMA/LABA therapy in real life.


Assuntos
Agonistas de Receptores Adrenérgicos beta 2 , Doença Pulmonar Obstrutiva Crônica , Administração por Inalação , Corticosteroides , Broncodilatadores , Quimioterapia Combinada , Humanos , Antagonistas Muscarínicos , Doença Pulmonar Obstrutiva Crônica/induzido quimicamente , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico
17.
J Econ Asymmetries ; 26: e00276, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36268201

RESUMO

The COVID-19 pandemic, which originated in Wuhan, China, precipitated the stock market crash of March 2020. According to published global data, the U.S. has been most affected by the tragedy throughout this outbreak. Understanding the degree of integration between the financial systems of the world's two largest economies, particularly during the COVID-19 pandemic, necessitates thorough research of the risk transmission from China's stock market to the U.S. stock market. This study examines the volatility transmission from the Chinese to the U.S. stock market from January 2001 to October 2020. We employ a variant form of the EGARCH (1,1) model with long-term control over the excessive volatility breakpoints identified by the ICSS algorithm. Since 2004, empirical evidence indicates that the volatility shocks of the Chinese stock market have frequently and negatively affected the volatility of the U.S. stock market. Most importantly, we explore that the COVID-19 pandemic vigorously and positively promoted the volatility infection from the Chinese equity market to the U.S. equity market in March 2020. This precious evidence endorses the asymmetric volatility transmission from the Chinese to the U.S. stock market when COVID-19 broke out. These experimental results provide profound insight into the risk contagion between the U.S. and China stock markets. They are also essential for securities investors to minimize portfolio risk. Furthermore, this paper suggests that globalization has carefully driven the integration of China's stock market with the international equity markets.

18.
Psychopharmacology (Berl) ; 239(6): 1665-1677, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35233648

RESUMO

BACKGROUND: Clinical studies suggest that psychedelics exert robust therapeutic benefits in a number of psychiatric conditions including substance use disorder. Preclinical studies focused on safety and efficacy of these compounds are necessary to determine the full range of psychedelics' effects. OBJECTIVES: The present study explores the behavioral pharmacology of structurally distinct psychedelics in paradigms associated with serotonin 2A receptor (5-HT2AR) activation and behavioral disruption in two rodent models. Utilizing the selective 5-HT2AR antagonist volinanserin, we aimed to provide further pharmacological assessment of psychedelic effects in rodents. METHODS: We compared volinanserin (0.0001-0.1 mg/kg) antagonism of the phenethylamine 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI, 1.0 mg/kg) and the ergoline lysergic acid diethylamide (LSD, 0.32 mg/kg) in preclinical assays predictive of hallucinations (head-twitch response or HTR in mice) and behavioral disruption (intracranial self-stimulation or ICSS in rats). Volinanserin antagonism of the phenethylamine mescaline, the tryptamine psilocybin, and the k-opioid receptor agonist salvinorin A was also evaluated in the rat ICSS assay. RESULTS: Volinanserin had similar potency, effectiveness, and time-course to attenuate DOI-induced HTR in mice and ICSS depression in rats. Volinanserin completely blocked LSD-induced HTR in mice, but not LSD-induced ICSS depression in rats. Volinanserin also reversed ICSS depression by mescaline, but it was only partially effective to reduce the effects of psilocybin, and it exacerbated ICSS depression by salvinorin A. CONCLUSION: Although hallucination-related HTR behavior induced by phenethylamine, ergoline, and tryptamine psychedelics appears to be 5-HT2AR-mediated, the receptor(s) responsible for behavioral disruptive effects may differ among these three structural classes.


Assuntos
Alucinógenos , Animais , Depressão/induzido quimicamente , Depressão/tratamento farmacológico , Fluorbenzenos , Alucinógenos/química , Alucinógenos/farmacologia , Dietilamida do Ácido Lisérgico/farmacologia , Mescalina , Camundongos , Fenetilaminas/farmacologia , Piperidinas , Psilocibina , Ratos , Receptor 5-HT2A de Serotonina , Roedores , Autoestimulação , Serotonina , Triptaminas
19.
JHEP Rep ; 4(12): 100602, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36352895

RESUMO

Background & Aims: Liver cancer (LC) and pancreatic cancer (PC) are often diagnosed at an advanced stage resulting in high mortality. High-quality survival data are rarely available for trend analyses over a long period. Methods: The Danish, Finnish, Norwegian, and Swedish cancer data were accessed at the NORDCAN database. We analysed relative 1- and 5-year survival trends in LC and PC between years 1970 and 2019. Results: Relative 1-year survival in LC for Nordic men and women was about 10% in the period between 1970 and 1974, and it increased moderately by year 2000 and steeply thereafter, eventually reaching 40-50%. The patterns in 5-year survival were similar, but after the year 2000, survival in Norway and Sweden increased steeply to 23%, whereas survival in Denmark and Finland lagged behind, reaching 10% to 15%. The patterns for PC also showed rapid improvement after the year 2000, with 1-year survival reaching 30% to 40% and 5-year survival reaching 10% for Finland and 15% for Norway and Sweden. Survival was best for patients diagnosed before age 50 years, and it was worst for older patients. For both cancers the difference between 1- and 5-year survival increased with time. Conclusions: Survival in LC and PC improved first modestly and then steeply over the 50-year period covered. The increase in 5-year survival was less than that of 1-year survival. The survival gains were most likely the result of earlier diagnosis, improved treatment, and better organised supportive care. The challenges are to keep up these positive trends, to extend survival benefits past Year 1, and to obtain similar results in elderly patients. Primary prevention through avoidance of risk factors would reduce case numbers. Lay summary: Liver and pancreatic cancers are among the most lethal of all cancers. In 50 years, survival in these cancers has slowly improved, and in the past 20 years, the development has been increasingly favourable. Widespread adoption of healthy lifestyles will be key to reducing the risk of these cancers.

20.
Psychopharmacology (Berl) ; 238(3): 845-855, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33410984

RESUMO

RATIONALE: Systemic administration of the tobacco smoke constituent nicotine stimulates brain reward function in rats. However, it is unknown if the inhalation of tobacco smoke affects brain reward function. OBJECTIVES: These experiments investigated if exposure to smoke from high-nicotine SPECTRUM research cigarettes increases reward function and affects the rewarding effects of nicotine in adult male and female Wistar rats. METHODS: Reward function after smoke or nicotine exposure was investigated using the intracranial self-stimulation (ICSS) procedure. A decrease in reward thresholds reflects an increase in reward function. In the first experiment, the rats were exposed to tobacco smoke for 40 min/day for 9 days, and the rewarding effects of nicotine (0.03-0.6 mg/kg) were investigated 3 weeks later. In the second experiment, the dose effects of tobacco smoke exposure (40-min sessions, 1-4 cigarettes burnt simultaneously) on reward function were investigated. RESULTS: Tobacco smoke exposure did not affect the nicotine-induced decrease in reward thresholds or response latencies in male and female rats. Smoke exposure lowered the brain reward thresholds to a similar degree in males and females and caused a greater decrease in latencies in females. There was a positive relationship between plasma nicotine and cotinine levels and the nicotine content of the SPECTRUM research cigarettes. Similar smoke exposure conditions led to higher plasma nicotine and cotinine levels in female than male rats. CONCLUSION: These findings indicate that tobacco smoke exposure enhances brain reward function but does not potentiate the rewarding effects of nicotine in male and female rats.


Assuntos
Encéfalo/efeitos dos fármacos , Nicotina/administração & dosagem , Tempo de Reação/efeitos dos fármacos , Recompensa , Poluição por Fumaça de Tabaco/efeitos adversos , Tabagismo/psicologia , Animais , Cotinina/sangue , Feminino , Masculino , Nicotina/sangue , Nicotina/farmacologia , Ratos , Ratos Wistar , Autoestimulação/efeitos dos fármacos , Nicotiana , Tabagismo/sangue
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