RESUMO
Cognitive flexibility is a crucial ability in humans that can be affected by chronic methamphetamine (METH) addiction. The present study aimed to elucidate the mechanisms underlying cognitive impairment in mice chronically administered METH via an oral self-administration method. Further, the effect of melatonin treatment on recovery of METH-induced cognitive impairment was also investigated. Cognitive performance of the mice was assessed using an attentional set shift task (ASST), and possible underlying neurotoxic mechanisms were investigated by proteomic and western blot analysis of the prefrontal cortex (PFC). The results showed that mice-administered METH for 21 consecutive days exhibited poor cognitive performance compared to controls. Cognitive deficit in mice partly recovered after METH withdrawal. In addition, mice treated with melatonin during METH withdrawal showed a higher cognitive recovery than vehicle-treated METH withdrawal mice. Proteomic and western blot analysis revealed that METH self-administration increased neurotoxic markers, including disruption to the regulation of mitochondrial function, mitophagy, and decreased synaptic plasticity. Treatment with melatonin during withdrawal restored METH-induced mitochondria and synaptic impairments. These findings suggest that METH-induced neurotoxicity partly depends on mitochondrial dysfunction leading to autophagy-dependent cell death and that the recovery of neurological impairments may be enhanced by melatonin treatment during the withdrawal period.
Assuntos
Disfunção Cognitiva , Melatonina , Metanfetamina , Síndrome de Abstinência a Substâncias , Humanos , Camundongos , Animais , Metanfetamina/toxicidade , Melatonina/farmacologia , Proteômica , Disfunção Cognitiva/induzido quimicamenteRESUMO
The ability to discriminate competing external stimuli and initiate contextually appropriate behaviours is a key brain function. Neurons in the deep superior colliculus (dSC) integrate multisensory inputs and activate descending projections to premotor pathways responsible for orienting, attention and defence, behaviours which involve adjustments to respiratory and cardiovascular parameters. However, the neural pathways that subserve the physiological components of orienting are poorly understood. We report that orienting responses to optogenetic dSC stimulation are accompanied by short-latency autonomic, respiratory and electroencephalographic effects in awake rats, closely mimicking those evoked by naturalistic alerting stimuli. Physiological responses were not accompanied by detectable aversion or fear, and persisted under urethane anaesthesia, indicating independence from emotional stress. Anterograde and trans-synaptic viral tracing identified a monosynaptic pathway that links the dSC to spinally projecting neurons in the medullary gigantocellular reticular nucleus (GiA), a key hub for the coordination of orienting and locomotor behaviours. In urethane-anaesthetized animals, sympathoexcitatory and cardiovascular, but not respiratory, responses to dSC stimulation were replicated by optogenetic stimulation of the dSC-GiA terminals, suggesting a likely role for this pathway in mediating the autonomic components of dSC-mediated responses. Similarly, extracellular recordings from putative GiA sympathetic premotor neurons confirmed short-latency excitatory inputs from the dSC. This pathway represents a likely substrate for autonomic components of orienting responses that are mediated by dSC neurons and suggests a mechanism through which physiological and motor components of orienting behaviours may be integrated without the involvement of higher centres that mediate affective components of defensive responses. KEY POINTS: Neurons in the deep superior colliculus (dSC) integrate multimodal sensory signals to elicit context-dependent innate behaviours that are accompanied by stereotypical cardiovascular and respiratory activities. The pathways responsible for mediating the physiological components of colliculus-mediated orienting behaviours are unknown. We show that optogenetic dSC stimulation evokes transient orienting, respiratory and autonomic effects in awake rats which persist under urethane anaesthesia. Anterograde tracing from the dSC identified projections to spinally projecting neurons in the medullary gigantocellular reticular nucleus (GiA). Stimulation of this pathway recapitulated autonomic effects evoked by stimulation of dSC neurons. Electrophysiological recordings from putative GiA sympathetic premotor neurons confirmed short latency excitatory input from dSC neurons. This disynaptic dSC-GiA-spinal sympathoexcitatory pathway may underlie autonomic adjustments to salient environmental cues independent of input from higher centres.
Assuntos
Formação Reticular , Colículos Superiores , Animais , Ratos , Colículos Superiores/fisiologia , Formação Reticular/fisiologia , Sistema Nervoso Autônomo/fisiologia , Neurônios/fisiologia , Vias Neurais/fisiologia , Uretana/farmacologiaRESUMO
The role of oxytocin in attenuating the abuse of licit and illicit drugs, including the psychostimulant methamphetamine, has been examined with increased ferocity in recent years. This is largely driven by the potential application of oxytocin as a pharmacotherapy. However, the neural mechanisms by which oxytocin modulates methamphetamine abuse are not well understood. Recent research identified an important role for the accumbens core and subthalamic nucleus in this process, which likely involves an interaction with dopamine, glutamate, GABA, and vasopressin. In addition to providing an overview of methamphetamine, the endogenous oxytocin system, and the effects of exogenous oxytocin on drug abuse, we propose a neural circuit through which exogenous oxytocin modulates methamphetamine abuse, focusing on its interaction with neurochemicals within the accumbens core and subthalamic nucleus. A growing understanding of exogenous oxytocin effects at a neurochemical and neurobiological level will assist in its evaluation as a pharmacotherapy for drug addiction.
Assuntos
Transtornos Relacionados ao Uso de Anfetaminas/tratamento farmacológico , Metanfetamina/farmacologia , Núcleo Accumbens/efeitos dos fármacos , Ocitocina/metabolismo , Núcleo Subtalâmico/efeitos dos fármacos , Animais , Humanos , Ocitocina/farmacologiaRESUMO
Caffeine is a psychostimulant commonly consumed with high levels of sugar. The increased availability of highly caffeinated, high sugar energy drinks could put some consumers at risk of being exposed to high doses of caffeine and sugar. Notably, research that has examined the consequences of this combination is limited. Here, we explored the effect of chronic exposure to caffeine and/or sugar on behavior and protein levels in the orbitofrontal cortex (OFC) of rats. The OFC brain region has been implicated in neuropsychiatric conditions, including obesity and addiction behaviors. Adult male Sprague-Dawley rats were treated for 26 days with control, caffeine (0.6 g/L), 10% sugar, or combination of both. Locomotor behavior was measured on the first and last day of treatment, then 1 week after treatment. Two hours following final behavioral testing, brains were rapidly removed and prepared for proteomic analysis of the OFC. Label-free quantitative shotgun analysis revealed that 21, 12, and 23% of proteins identified in the OFC were differentially expressed by sugar and/or caffeine. The results demonstrate that the intake of high levels of sugar and/or low to moderate levels of caffeine has different behavioral consequences. Moreover, each treatment results in a unique proteomic profile with different implications for neural health.
Assuntos
Cafeína/farmacologia , Estimulantes do Sistema Nervoso Central/farmacologia , Carboidratos da Dieta/farmacologia , Córtex Pré-Frontal/efeitos dos fármacos , Proteoma/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Bebidas/efeitos adversos , Cafeína/efeitos adversos , Estimulantes do Sistema Nervoso Central/efeitos adversos , Carboidratos da Dieta/efeitos adversos , Locomoção/efeitos dos fármacos , Masculino , Córtex Pré-Frontal/fisiologia , Proteoma/análise , Proteômica , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Aumento de Peso/efeitos dos fármacosRESUMO
In most Westernized societies, there has been an alarming increase in the consumption of sugar-sweetened drinks. For many adults these drinks represent a substantial proportion of their total daily caloric intake. Here we investigated whether extended exposure to sugar changes behavior and protein expression in the orbitofrontal cortex (OFC). Male adult Sprague-Dawley rats (n = 8 per group) were treated for 26 days with either water or a 10% sucrose solution. Locomotor behavior was measured on the first and last day of treatment, then 1 week after treatment. Following the 1-week period free from treatment, sucrose treated rats were significantly more active than the control. Two hours following final behavioral testing, brains were rapidly removed and prepared for proteomic analysis of the OFC. Label free quantitative shotgun proteomic analyses of three rats from each group found 290 proteins were differentially expressed in the sucrose treated group when compared to the control group. Major changes in the proteome were seen in proteins related to energy metabolism, mitochondrial function and the cellular response to stress. This research does not seek to suggest that sugar will cause specific neurological disorders, however similar changes in proteins have been seen in neurological disorders such as Alzheimer's disease, Parkinson's disease and schizophrenia.
Assuntos
Córtex Pré-Frontal/metabolismo , Proteoma/metabolismo , Sacarose/metabolismo , Animais , Metabolismo dos Carboidratos , Bebidas Gaseificadas/efeitos adversos , Ingestão de Energia , Metabolismo Energético , Glucose/metabolismo , Masculino , Mitocôndrias/metabolismo , Atividade Motora , Estresse Oxidativo , Córtex Pré-Frontal/fisiologia , Proteoma/análise , Proteômica , Ratos , Ratos Sprague-Dawley , Sacarose/efeitos adversos , Aumento de PesoRESUMO
Caffeine is a plant-derived psychostimulant and a common additive found in a wide range of foods and pharmaceuticals. The orbitofrontal cortex (OFC) is rapidly activated by flavours, integrates gustatory and olfactory information, and plays a critical role in decision-making, with dysfunction contributing to psychopathologies and neurodegenerative conditions. This study investigated whether long-term consumption of caffeine causes changes to behavior and protein expression in the OFC. Male adult Sprague-Dawley rats (n = 8 per group) were treated for 26 days with either water or a 0.6 g/L caffeine solution. Locomotor behavior was measured on the first and last day of treatment, then again after 9 days treatment free following exposure to a mild stressor. When tested drug free, caffeine-treated animals were hyperactive compared to controls. Two hours following final behavioral testing, brains were rapidly removed and prepared for proteomic analysis of the OFC. Label free shotgun proteomics found 157 proteins differentially expressed in the caffeine-drinking rats compared to control. Major proteomic effects were seen for cell-to-cell communication, cytoskeletal regulation, and mitochondrial function. Similar changes have been observed in neurological disorders including Alzheimer's disease, Parkinson's disease, and schizophrenia.
Assuntos
Cafeína/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Córtex Pré-Frontal/química , Proteômica/métodos , Animais , Comunicação Celular/efeitos dos fármacos , Citoesqueleto/efeitos dos fármacos , Perfilação da Expressão Gênica , Masculino , Mitocôndrias/efeitos dos fármacos , Atividade Motora/efeitos dos fármacos , Doenças do Sistema Nervoso/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
KEY POINTS: Methamphetamine (METH) abuse is escalating worldwide, with the most common cause of death resulting from cardiovascular failure and hyperthermia; however, the underlying physiological mechanisms are poorly understood. Systemic administration of METH in anaesthetised rats reduced the effectiveness of some protective cardiorespiratory reflexes, increased central respiratory activity independently of metabolic function, and increased heart rate, metabolism and respiration in a pattern indicating that non-shivering thermogenesis contributes to the well-described hyperthermia. In animals that showed METH-induced behavioural sensitisation following chronic METH treatment, no changes were evident in baseline cardiovascular, respiratory and metabolic measures and the METH-evoked effects in these parameters were similar to those seen in saline-treated or drug naïve animals. Physiological effects evoked by METH were retained but were neither facilitated nor depressed following chronic treatment with METH. These data highlight and identify potential mechanisms for targeted intervention in patients vulnerable to METH overdose. Methamphetamine (METH) is known to promote cardiovascular failure or life-threatening hyperthermia; however, there is still limited understanding of the mechanisms responsible for evoking the physiological changes. In this study, we systematically determined the effects on both autonomic and respiratory outflows, as well as reflex function, following acute and repeated administration of METH, which enhances behavioural responses. Arterial pressure, heart rate, phrenic nerve discharge amplitude and frequency, lumbar and splanchnic sympathetic nerve discharge, interscapular brown adipose tissue and core temperatures, and expired CO2 were measured in urethane-anaesthetised male Sprague-Dawley rats. Novel findings include potent increases in central inspiratory drive and frequency that are not dependent on METH-evoked increases in expired CO2 levels. Increases in non-shivering thermogenesis correlate with well-described increases in body temperature and heart rate. Unexpectedly, METH evoked minor effects on both sympathetic outflows and mean arterial pressure. METH modified cardiorespiratory reflex function in response to hypoxia, hypercapnia and baroreceptor unloading. Chronically METH-treated rats failed to exhibit changes in baseline sympathetic, cardiovascular, respiratory and metabolic parameters. The tonic and reflex cardiovascular, respiratory and metabolic responses to METH challenge were similar to those seen in saline-treated and drug naive animals. Overall, these findings describe independent and compound associations between physiological systems evoked by METH and serve to highlight that a single dose of METH can significantly impact basic homeostatic systems and protective functions. These effects of METH persist even following chronic METH treatment.
Assuntos
Metanfetamina/farmacologia , Tecido Adiposo Marrom/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Temperatura Corporal/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Região Lombossacral/fisiologia , Masculino , Atividade Motora/efeitos dos fármacos , Nervo Frênico/fisiologia , Ratos Sprague-Dawley , Reflexo/efeitos dos fármacos , Respiração/efeitos dos fármacos , Nervos Esplâncnicos/fisiologia , Sistema Nervoso Simpático/fisiologia , Termogênese/efeitos dos fármacosRESUMO
The psychostimulant methamphetamine (METH) is an addictive illicit drug. Systemic administration of the neuropeptide oxytocin modulates METH-related reward and METH-seeking behaviour. Recent findings demonstrated a reduction in METH-induced reward by oxytocin administration into the nucleus accumbens (NAc) core. It is not known, however, if oxytocin acts in this region to reduce relapse to METH-seeking behaviour. Using the drug reinstatement paradigm in rats experienced at METH self-administration, we aimed to determine whether oxytocin pre-treatment within the NAc core would reduce relapse to METH use and if this could be reversed by the co-administration of the oxytocin receptor (OTR) antagonist desGly-NH2,d(CH2)5[D-Tyr2,Thr4]OVT. Male Sprague-Dawley rats underwent surgery to implant an intravenous jugular vein catheter and bilateral microinjection cannulae in the NAc core. Rats were then trained to self-administer intravenous METH (0.1 mg/kg/infusion) by lever press during 2-hour fixed ratio 1 scheduled sessions for 20 days. Following extinction of lever press activity, the effect of microinjecting saline, oxytocin (0.5 pmol, 1.5 pmol, 4.5 pmol) or co-administration of oxytocin (1.5 pmol) and desGly-NH2,d(CH2)5[D-Tyr2,Thr4]OVT (1 nmol, 3 nmol) in the NAc core (500 nl/side) was examined on METH-primed (1 mg/kg, i.p.) reinstatement of drug-seeking behaviour. Our results showed oxytocin directly administered into the NAc core decreased METH-primed reinstatement in a dose-dependent manner. Co-administration of the selective OTR antagonist did not specifically reverse the inhibitory effects of oxytocin on METH priming, suggesting mediation by receptors other than the OTR. These findings highlight an important modulatory effect of oxytocin in the NAc core on relapse to METH seeking.
Assuntos
Estimulantes do Sistema Nervoso Central/farmacologia , Comportamento de Procura de Droga/efeitos dos fármacos , Metanfetamina/farmacologia , Neuropeptídeos/farmacologia , Núcleo Accumbens/efeitos dos fármacos , Ocitocina/farmacologia , Análise de Variância , Animais , Condicionamento Operante/efeitos dos fármacos , Relação Dose-Resposta a Droga , Extinção Psicológica/efeitos dos fármacos , Injeções Intravenosas , Masculino , Ratos Sprague-Dawley , AutoadministraçãoRESUMO
The neuropeptide oxytocin (OT), given acutely, reduces self-administration of the psychostimulant drug methamphetamine (METH). Additionally, chronic OT administration to adolescent rats reduces levels of alcohol consumption in adulthood, suggesting developmental neuroplasticity in the OT system relevant to addiction-related behaviors. Here, we examined whether OT exposure during adolescence might subsequently inhibit METH self-administration in adulthood. Female Sprague-Dawley rats were administered vehicle or OT (1 mg/kg, i.p.) once daily from postnatal days (PND) 28 to 37 (adolescence). At PND 62 (adulthood), rats were trained to self-administer METH (intravenous, i.v.) in daily 2-hour sessions for 10 days under a fixed ratio 1 (FR1) reinforcement schedule, followed by determination of dose-response functions (0.01-0.3 mg/kg/infusion, i.v.) under both FR1 and progressive ratio (PR) schedules of reinforcement. Responding was then extinguished, and relapse to METH-seeking behavior assessed following priming doses of non-contingent METH (0.1-1 mg/kg, i.p.). Finally, plasma was collected to determine pre-treatment effects on OT and corticosterone levels. Results showed that OT pre-treatment did not significantly inhibit the acquisition of METH self-administration or FR1 responding. However, rats pre-treated with OT responded significantly less for METH under a PR reinforcement schedule, and showed reduced METH-primed reinstatement with the 1 mg/kg prime. Plasma OT levels were also significantly higher in OT pre-treated rats. These results confirm earlier observations that adolescent OT exposure can subtly, yet significantly, inhibit addiction-relevant behaviors in adulthood.
Assuntos
Estimulantes do Sistema Nervoso Central/farmacologia , Comportamento de Procura de Droga/efeitos dos fármacos , Metanfetamina/farmacologia , Neuropeptídeos/farmacologia , Ocitocina/farmacologia , Esquema de Reforço , Animais , Relação Dose-Resposta a Droga , Extinção Psicológica/efeitos dos fármacos , Feminino , Ratos Sprague-Dawley , AutoadministraçãoRESUMO
Repeat administration of psychostimulants, such as methamphetamine, produces a progressive increase in locomotor activity (behavioral sensitization) in rodents that is believed to represent the underlying neurochemical changes driving psychoses. Alterations to the prefrontal cortex (PFC) are suggested to mediate the etiology and maintenance of these behavioral changes. As such, the aim of the current study was to investigate changes to protein expression in the PFC in male rats sensitized to methamphetamine using quantitative label-free shotgun proteomics. A methamphetamine challenge resulted in a significant sensitized locomotor response in methamphetamine pretreated animals compared to saline controls. Proteomic analysis revealed 96 proteins that were differentially expressed in the PFC of methamphetamine treated rats, with 20% of these being previously implicated in the neurobiology of schizophrenia in the PFC. We identified multiple biological functions in the PFC that appear to be commonly altered across methamphetamine-induced sensitization and schizophrenia, and these include synaptic regulation, protein phosphatase signaling, mitochondrial function, and alterations to the inhibitory GABAergic network. These changes could inform how alterations to the PFC could underlie the cognitive and behavioral dysfunction commonly seen across psychoses and places such biological changes as potential mediators in the maintenance of psychosis vulnerability.
Assuntos
Sensibilização do Sistema Nervoso Central/efeitos dos fármacos , Metanfetamina/efeitos adversos , Córtex Pré-Frontal/metabolismo , Proteoma/metabolismo , Transtornos Psicóticos/fisiopatologia , Sinapses/metabolismo , Animais , Cromatografia Líquida , Bases de Dados de Proteínas , Eletroforese em Gel de Poliacrilamida , Masculino , Modelos Neurológicos , Córtex Pré-Frontal/efeitos dos fármacos , Proteoma/efeitos dos fármacos , Transtornos Psicóticos/metabolismo , Ratos , Sinapses/efeitos dos fármacos , Espectrometria de Massas em TandemRESUMO
The orexins are hypothalamic neuropeptides most well known for their roles in regulating feeding and sleeping behaviors. Recent findings suggest that orexin-A may also modulate anxiety, although how and when the orexin system is involved remains unclear. To address this, we investigated the dose-dependent effects of the orexin-1 receptor antagonist SB-334867 in two rodent models of anxiety: the cat odor avoidance model and the elevated plus maze. In both models we tested the effects of SB-334867 when anxiety is novel (Trial 1) and familiar (Trial 2). In the first experiment, Wistar rats were treated with vehicle or SB-334867 (5, 10 or 20mg/kg, i.p.) prior to their first or second exposure to cat odor. During Trial 1, rats treated with 10mg/kg of SB-334867 approached the cat odor stimulus more than vehicle-treated rats. During Trial 2 the effects were more marked, with 10mg/kg of SB-334867 increasing approach times, increasing the number of times rats exited the hide box to engage in exploratory behavior, and decreasing overall hide times. In addition, the 20mg/kg dose decreased general activity during Trial 2. In the second experiment, the effects of SB-334867 (10 and 20mg/kg) were tested in the elevated plus maze. There were no significant differences produced by drug treatment during either Trial 1 or Trial 2. Results suggest that SB-334867 decreases anxiety induced by some, but not all, stressors.
Assuntos
Ansiedade/tratamento farmacológico , Comportamento Animal/fisiologia , Benzoxazóis/farmacologia , Antagonistas dos Receptores de Orexina , Ureia/análogos & derivados , Animais , Ansiedade/induzido quimicamente , Ansiedade/etiologia , Aprendizagem da Esquiva/efeitos dos fármacos , Aprendizagem da Esquiva/fisiologia , Comportamento Animal/efeitos dos fármacos , Benzoxazóis/administração & dosagem , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Naftiridinas , Odorantes , Ratos , Ratos Wistar , Reconhecimento Psicológico/fisiologia , Estresse Psicológico/complicações , Ureia/administração & dosagem , Ureia/farmacologiaRESUMO
RATIONALE: Alcopop beverages are generally the first alcoholic beverage that young females drink which contain high levels of sugar and alcohol. The over-consumption of these drinks may encourage alcohol co-administration with methamphetamine (METH) impacting on drinking behaviour and glial function. AIMS: The aims of this study were to evaluate the effect of adolescent binge alcohol exposure on consumption level, anxiety-like behaviour, cross-sensitization with METH and on astrocyte expression in reward related brain regions. METHODS: Adolescent female Sprague-Dawley rats had daily 1-hour oral alcohol consumption of alcopop (ALCP; with sucrose) or ethanol-only (ETOH; without sucrose), transitioned from 5 to 15% (v/v) ethanol content for 34 days. Water and sucrose groups act as controls. During alcohol withdrawal, rats were tested for anxiety on the elevated plus maze (EPM) and locomotor activity following saline or METH (1 mg/kg i.p) treatment. Brains were then collected to assess astrocyte immunofluorescence for glial fibrillary acidic protein (GFAP) in reward-related brain regions. RESULTS: Rats pretreated with 5% ALCP consumed significantly more volume and ethanol intake when compared to 5% EtOH rats. Both ALCP and EtOH groups had a higher preference ratio for 5% than 15% alcohol solutions and ALCP rats had greater ethanol intake at 15% than EtOH rats. Alcohol withdrawal showed no significant differences between groups on anxiety, METH cross-sensitization effects or GFAP intensity in the regions studied. CONCLUSIONS: Overall, the addition of sucrose to alcoholic solutions encouraged female rats to consume larger volumes and greater ethanol intake compared to ethanol-only solutions, yet did not have long lasting effects on behaviour and astrocytes.
Assuntos
Ansiedade , Astrócitos , Consumo Excessivo de Bebidas Alcoólicas , Encéfalo , Etanol , Proteína Glial Fibrilar Ácida , Metanfetamina , Ratos Sprague-Dawley , Síndrome de Abstinência a Substâncias , Animais , Feminino , Astrócitos/metabolismo , Astrócitos/efeitos dos fármacos , Síndrome de Abstinência a Substâncias/metabolismo , Ratos , Metanfetamina/administração & dosagem , Metanfetamina/farmacologia , Consumo Excessivo de Bebidas Alcoólicas/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Etanol/administração & dosagem , Etanol/farmacologia , Ansiedade/metabolismo , Comportamento Animal/efeitos dos fármacos , Estimulantes do Sistema Nervoso Central/farmacologia , Estimulantes do Sistema Nervoso Central/administração & dosagemRESUMO
The typical Western diet, rich in high saturated fat and refined sugar (HFS), has been shown to increase cognitive decline with aging and Alzheimer's disease, and to affect cognitive functions that are dependent on the hippocampus, including memory processes and reversal learning. To investigate neurophysiological changes underlying these impairments, we employed a proteomic approach to identify differentially expressed proteins in the rat dorsal and ventral hippocampus following maintenance on an HFS diet. Rats maintained on the HFS diet for 8 weeks were impaired on a novel object recognition task that assesses memory and on a Morris Water Maze task assessing reversal learning. Quantitative label-free shotgun proteomic analysis was conducted on biological triplicates for each group. For the dorsal hippocampus, 59 proteins were upregulated and 36 downregulated in the HFS group compared to controls. Pathway ana-lysis revealed changes to proteins involved in molecular transport and cellular and molecular signaling, and changes to signaling pathways including calcium signaling, citrate cycle, and oxidative phosphorylation. For the ventral hippocampus, 25 proteins were upregulated and 27 downregulated in HFS fed rats. Differentially expressed proteins were involved in cell-to-cell signaling and interaction, and cellular and molecular function. Changes to signaling pathways included protein ubiquitination, ubiquinone biosynthesis, oxidative phosphorylation, and mitochondrial dysfunction. This is the first shotgun proteomics study to examine protein changes in the hippocampus following long-term consumption of a HFS diet, identifying changes to a large number of proteins including those involved in synaptic plasticity and energy metabolism. All MS data have been deposited in the ProteomeXchange with identifier PXD000028.
Assuntos
Dieta Hiperlipídica , Carboidratos da Dieta/farmacologia , Hipocampo/metabolismo , Proteômica/métodos , Animais , Comportamento Animal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Condicionamento Operante/efeitos dos fármacos , Ingestão de Energia/efeitos dos fármacos , Reação de Fuga/efeitos dos fármacos , Comportamento Exploratório/efeitos dos fármacos , Extinção Psicológica/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Proteólise/efeitos dos fármacos , Proteoma/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Ubiquitinação/efeitos dos fármacosRESUMO
The prefrontal cortex (PFC) is referred to as the visceral motor cortex; however, little is known about whether this region influences respiratory or metabolic outflows. The aim of this study was to describe simultaneous changes in respiratory, metabolic and cardiovascular functions evoked by disinhibition of the medial PFC (mPFC) and adjacent lateral septal nucleus (LSN). In urethane-anaesthetized rats, bicuculline methiodide was microinjected (2 mm; GABA-A receptor antagonist) into 90 sites in the mPFC at 0.72-4.00 mm from bregma. Phrenic nerve amplitude and frequency, arterial pressure, heart rate, splanchnic and lumbar sympathetic nerve activities (SNA), expired CO2, and core and brown adipose tissue temperatures were measured. Novel findings included disturbances to respiratory rhythm evoked from all subregions of the mPFC. Injections into the cingulate cortex evoked reductions in central respiratory function exclusively, whereas in ventral sites, particularly the infralimbic region, increases in respiratory drive and frequency, and metabolic and cardiac outflows were evoked. Disinhibition of sites in surrounding regions revealed that the LSN could evoke cardiovascular changes accompanied by distinct oscillations in SNA, as well as increases in respiratory amplitude. We show that activation of neurons within the mPFC and LSN influence respiratory, metabolic and cardiac outflows in a site-dependent manner. This study has implications with respect to the altered PFC neuronal activity seen in stress-related and mental health disorders, and suggests how basic physiological systems may be affected.
Assuntos
Bicuculina/análogos & derivados , Antagonistas GABAérgicos/farmacologia , Córtex Pré-Frontal/efeitos dos fármacos , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/fisiologia , Animais , Pressão Arterial/efeitos dos fármacos , Bicuculina/farmacologia , Temperatura Corporal , Dióxido de Carbono/metabolismo , Frequência Cardíaca/efeitos dos fármacos , Masculino , Nervo Frênico/efeitos dos fármacos , Nervo Frênico/fisiologia , Córtex Pré-Frontal/fisiologia , Ratos , Ratos Sprague-Dawley , Respiração/efeitos dos fármacos , Núcleos Septais/efeitos dos fármacos , Núcleos Septais/fisiologia , Nervos Esplâncnicos/efeitos dos fármacos , Nervos Esplâncnicos/fisiologiaRESUMO
The subthalamic nucleus (STh) is increasingly recognized as an important region involved in the motivation for drug reward. It is not yet known if dopamine, the neurotransmitter primarily responsible for reward signaling, is also involved in mediating reward-related activity in the STh. The neuropeptide oxytocin acts within the STh to reduce the rewarding effects of the psychostimulant methamphetamine, through a proposed interaction with dopamine. However, the mechanisms of this interaction are unclear. The current study aimed to determine whether (i) dopamine microinjected into the STh would result in a significant place preference following a single-trial conditioning session, (ii) co-administered dopamine receptor antagonist would block the formation of a conditioned place preference (CPP) for dopamine, (iii) co-administered oxytocin would prevent CPP for dopamine and (iv) whether the selective oxytocin antagonist desGly-NH(2),d(CH(2))(5)[D-Tyr(2),Thr(4)]OVT, when co-administered with oxytocin and dopamine, would reverse the effects of oxytocin and result in a CPP for dopamine. Results showed that male Sprague Dawley rats i) formed a preference for the context paired with dopamine (100 nmol/side) administration into the STh, which was prevented by co-administration of ii) the mixed dopamine receptor antagonist fluphenazine (10 nmol/side) or iii) oxytocin (0.6 pmol/side), [corrected] with the oxytocin effect on dopamine CPP reversed by the co-administration of the oxytocin receptor antagonist (3 nmol/side). These data suggest that dopamine neurotransmission in the STh produces rewarding effects that can be reduced by activation of local oxytocin receptors.
Assuntos
Dopamina/farmacologia , Ocitocina/farmacologia , Recompensa , Núcleo Subtalâmico/efeitos dos fármacos , Animais , Estimulantes do Sistema Nervoso Central/farmacologia , Condicionamento Psicológico/efeitos dos fármacos , Dopamina/administração & dosagem , Antagonistas de Dopamina/farmacologia , Antagonismo de Drogas , Masculino , Atividade Motora/efeitos dos fármacos , Ocitocina/administração & dosagem , Ratos , Ratos Sprague-Dawley , Receptores de Ocitocina/antagonistas & inibidores , Receptores de Ocitocina/metabolismo , Núcleo Subtalâmico/metabolismo , Núcleo Subtalâmico/fisiologiaRESUMO
Cannabis has been used historically for both medicinal and recreational purposes, with the most notable cannabinoids being cannabidiol (CBD) and tetrahydrocannabinol (THC). Although their therapeutic effects have been well studied and their recreational use is highly debated, the underlying mechanisms of their biological effects remain poorly defined. In this study, we use isobaric tag-based sample multiplexed proteome profiling to investigate protein abundance differences in the human neuroblastoma SH-SY5Y cell line treated with CBD and THC. We identified significantly regulated proteins by each treatment and performed a pathway classification and associated protein-protein interaction analysis. Our findings suggest that these treatments may lead to mitochondrial dysfunction and induce endoplasmic reticulum stress. These data can potentially be interrogated further to investigate the potential role of CBD and THC in various biological and disease contexts, providing a foundation for future studies.
RESUMO
INTRODUCTION: Methamphetamine (METH, "ice") is a potent and addictive psychostimulant. Abuse of METH perturbs neurotransmitter systems and induces neurotoxicity; however, the neurobiological mechanisms which underlie addiction to METH are not fully understood, limiting the efficacy of available treatments. Here we investigate METH-induced changes to neuronal nitric oxide synthase (nNOS), parvalbumin and calretinin-expressing GABAergic interneuron populations within the nucleus accumbens (NAc), prefrontal cortex (PFC) and orbitofrontal cortex (OFC). We hypothesise that dysfunction or loss of these GABAergic interneuron populations may disrupt the excitatory/inhibitory balance within the brain. METHODS: Male Long Evans rats (N = 32) were trained to lever press for intravenous METH or received yoked saline infusions. Following 14 days of behavioural extinction, animals were given a non-contingent injection of saline or METH (1 mg/kg, IP) to examine drug-primed reinstatement to METH-seeking behaviours. Ninety minutes post-IP injection, animals were culled and brain sections were analysed for Fos, nNOS, parvalbumin and calretinin immunoreactivity in eight distinct subregions of the NAc, PFC and OFC. RESULTS: METH exposure differentially affected GABAergic populations, with METH self-administration increasing nNOS immunoreactivity at distinct locations in the prelimbic cortex and decreasing parvalbumin immunoreactivity in the NAc. METH self-administration triggered reduced calretinin immunoreactivity, whilst acute METH administration produced a significant increase in calretinin immunoreactivity. As expected, non-contingent METH-priming treatment increased Fos immunoreactivity in subregions of the NAc and PFC. CONCLUSION: Here we report that METH exposure in this model may alter the function of GABAergic interneurons in more subtle ways, such as alterations in neuronal firing or synaptic connectivity.
Assuntos
Estimulantes do Sistema Nervoso Central , Metanfetamina , Ácido gama-Aminobutírico/metabolismo , Animais , Calbindina 2 , Estimulantes do Sistema Nervoso Central/farmacologia , Interneurônios , Masculino , Metanfetamina/farmacologia , Núcleo Accumbens , Parvalbuminas , Córtex Pré-Frontal , Ratos , Ratos Long-Evans , AutoadministraçãoRESUMO
RATIONALE: Stress exposure during adolescence contributes to developing a methamphetamine (METH) use disorder. However, most of the studies investigating addiction-related behaviours include only male rodents, despite METH addiction rates being higher in females. Furthermore, animal studies investigating the effects of stress on methamphetamine addiction have used only basic self-administration models which may not be sensitive to the effects of stress. OBJECTIVES: This project explored whether adolescent isolation stress exposure increases the incidence of four key addiction-related behaviours in female rats. METHODS: Thirty-two female rat pups were caged in groups of four or individually during adolescence from postnatal (PND) day 22, with the latter being re-socialised in groups of four on PND 43. In adulthood, rats were tested for addiction-like behaviours in a METH self-administration paradigm modelling motivation to take METH, persistence in drug-seeking behaviour when METH was not available, resistance to extinction, and propensity to reinstate after a period of withdrawal. RESULTS: Adolescent social isolation resulted in lower METH intake during acquisition; however, the paradigm modelling drug-seeking when the drug was unavailable engendered intermittent METH bingeing in all rats, abolishing the group differences in intake during this phase. Adolescent social isolation also accelerated extinction of non-reinforced lever pressing, and increased stress-primed reinstatement, compared to the group-housed rats. CONCLUSIONS: Adolescent social isolation stress alters various methamphetamine addiction-like behaviours in female rats.
Assuntos
Transtornos Relacionados ao Uso de Anfetaminas , Estimulantes do Sistema Nervoso Central , Metanfetamina , Transtornos Relacionados ao Uso de Anfetaminas/tratamento farmacológico , Animais , Comportamento de Procura de Droga , Extinção Psicológica , Feminino , Masculino , Metanfetamina/farmacologia , Ratos , Ratos Sprague-Dawley , Autoadministração , Isolamento SocialRESUMO
Early life stress (ELS) is associated with perturbed neural development and augmented vulnerability to mental health disorders, including addiction. How ELS changes the brain to increase addiction risk is poorly understood, and there are no therapies which target this ELS-induced vulnerability. ELS disrupts the oxytocin system, which can modulate addiction susceptibility, suggesting that targeting the oxytocin system may be therapeutic in this ELS-addiction comorbidity. Therefore, we determined whether adolescent oxytocin treatment after ELS could: (1) reduce vulnerability to anxiety, social deficits, and methamphetamine-taking and reinstatement; and (2) restore hypothalamic oxytocin and corticotropin-releasing factor expressing neurons and peripheral oxytocin and corticosterone levels. Long Evans pups underwent maternal separation (MS) for either 15 min or 360 min on postnatal days (PND) 1-21. During adolescence (PNDs 28-42), rats received a daily injection of either oxytocin or saline. In Experiment 1, adult rats were assessed using the elevated plus-maze, social interaction procedure, and methamphetamine self-administration procedure, including extinction, and cue-, methamphetamine- and yohimbine-induced reinstatement. In Experiment 2, plasma for enzyme immunoassays and brain tissue for immunofluorescence were collected from adult rats after acute stress exposure. Adolescent oxytocin treatment ameliorated ELS-induced anxiety and reduced methamphetamine- and yohimbine-induced reinstatement in both sexes, and suppressed methamphetamine intake and facilitated extinction in males only. Additionally, adolescent oxytocin treatment after ELS restored oxytocin-immunoreactive cells and stress-induced oxytocin levels in males, and attenuated stress-induced corticosterone levels in both sexes. Adolescent oxytocin treatment reverses some of the ELS effects on later-life psychopathology and vulnerability to addiction.
Assuntos
Transtornos Relacionados ao Uso de Anfetaminas , Metanfetamina , Ocitocina , Estresse Psicológico , Transtornos Relacionados ao Uso de Anfetaminas/tratamento farmacológico , Animais , Corticosterona/análise , Extinção Psicológica , Feminino , Masculino , Privação Materna , Metanfetamina/efeitos adversos , Ocitocina/uso terapêutico , Ratos , Ratos Long-Evans , Estresse Psicológico/tratamento farmacológico , Ioimbina/farmacologiaRESUMO
RATIONALE: Cannabidiol (CBD) and cannabidiolic acid (CBDA) are non-psychoactive components of the cannabis plant. CBD has been well characterised to have anxiolytic and anticonvulsant activity, whereas the behavioural effects of CBDA are less clear. Preclinical and clinical data suggests that CBD has antipsychotic properties and reduces methamphetamine self-administration in rats. An animal model that is commonly used to mimic the neurochemical changes underlying psychosis and drug dependence is methamphetamine (METH) sensitisation, where repeated administration of the psychostimulant progressively increases the locomotor effects of METH. OBJECTIVE: The aim of this study was to determine whether CBD or CBDA attenuate METH-induced sensitisation of locomotor hyperactivity in rats. METHODS: Eighty-six male Sprague Dawley rats underwent METH sensitisation protocol where they were subjected to daily METH (1 mg/kg on days 2 and 8, 5 mg/kg on days 3-7; i.p.) injections for 7 days. After 21 days of withdrawal, rats were given a prior injection of CBD (0, 40 and 80 mg/kg; i.p.) or CBDA (0, 0.1, 10 and 1000 µg/kg; i.p.) and challenged with acute METH (1 mg/kg; i.p.). Locomotor activity was then measured for 60 min. RESULTS: Rats displayed robust METH sensitisation as evidenced by increased locomotor activity to METH challenge in METH-pretreated versus SAL-pretreated rats. CBD (40 and 80 mg/kg) reduced METH-induced sensitisation. There was no effect of any CBDA doses on METH sensitisation or acute METH-induced hyperactivity. CONCLUSION: These results demonstrate that CBD, but not CBDA, reduces METH sensitisation of locomotor activity in rats at pharmacologically effective doses, thus reinforcing evidence that CBD has anti-addiction and antipsychotic properties.