RESUMO
Dopamine D2 receptors (D2Rs) are densely expressed in the striatum and have been linked to neuropsychiatric disorders such as schizophrenia1,2. High-affinity binding of dopamine suggests that D2Rs detect transient reductions in dopamine concentration (the dopamine dip) during punishment learning3-5. However, the nature and cellular basis of D2R-dependent behaviour are unclear. Here we show that tone reward conditioning induces marked stimulus generalization in a manner that depends on dopamine D1 receptors (D1Rs) in the nucleus accumbens (NAc) of mice, and that discrimination learning refines the conditioning using a dopamine dip. In NAc slices, a narrow dopamine dip (as short as 0.4 s) was detected by D2Rs to disinhibit adenosine A2A receptor (A2AR)-mediated enlargement of dendritic spines in D2R-expressing spiny projection neurons (D2-SPNs). Plasticity-related signalling by Ca2+/calmodulin-dependent protein kinase II and A2ARs in the NAc was required for discrimination learning. By contrast, extinction learning did not involve dopamine dips or D2-SPNs. Treatment with methamphetamine, which dysregulates dopamine signalling, impaired discrimination learning and spine enlargement, and these impairments were reversed by a D2R antagonist. Our data show that D2Rs refine the generalized reward learning mediated by D1Rs.
Assuntos
Espinhas Dendríticas/fisiologia , Aprendizagem por Discriminação/fisiologia , Receptores de Dopamina D2/metabolismo , Animais , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Condicionamento Clássico/efeitos dos fármacos , Espinhas Dendríticas/efeitos dos fármacos , Aprendizagem por Discriminação/efeitos dos fármacos , Dopamina/metabolismo , Antagonistas dos Receptores de Dopamina D2/farmacologia , Extinção Psicológica/efeitos dos fármacos , Masculino , Metanfetamina/antagonistas & inibidores , Metanfetamina/farmacologia , Camundongos , Plasticidade Neuronal , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Optogenética , Receptor A2A de Adenosina/metabolismo , Receptores de Dopamina D1/metabolismo , Recompensa , Transdução de Sinais/efeitos dos fármacos , Sinapses/metabolismoRESUMO
The serotonin transporter (SERT) is a member of the SLC6 neurotransmitter transporter family that mediates serotonin reuptake at presynaptic nerve terminals. SERT is the target of both therapeutic antidepressant drugs and psychostimulant substances such as cocaine and methamphetamines, which are small molecules that perturb normal serotonergic transmission by interfering with serotonin transport. Despite decades of studies, important functional aspects of SERT such as the oligomerization state of native SERT and its interactions with potential proteins remain unresolved. Here, we develop methods to isolate SERT from porcine brain (pSERT) using a mild, nonionic detergent, utilize fluorescence-detection size-exclusion chromatography to investigate its oligomerization state and interactions with other proteins, and employ single-particle cryo-electron microscopy to elucidate the structures of pSERT in complexes with methamphetamine or cocaine, providing structural insights into psychostimulant recognition and accompanying pSERT conformations. Methamphetamine and cocaine both bind to the central site, stabilizing the transporter in an outward open conformation. We also identify densities attributable to multiple cholesterol or cholesteryl hemisuccinate (CHS) molecules, as well as to a detergent molecule bound to the pSERT allosteric site. Under our conditions of isolation, we find that pSERT is best described as a monomeric entity, isolated without interacting proteins, and is ensconced by multiple cholesterol or CHS molecules.
Assuntos
Estimulantes do Sistema Nervoso Central , Cocaína , Metanfetamina , Animais , Suínos , Proteínas da Membrana Plasmática de Transporte de Serotonina , Microscopia Crioeletrônica , Detergentes , Serotonina , Cocaína/farmacologia , Metanfetamina/farmacologiaRESUMO
We investigated sex differences in dopamine (DA) release in the nucleus accumbens (NAc) and dorsolateral striatum (DLS) using a chronic 16-channel carbon fiber electrode and fast-scan cyclic voltammetry (FSCV). Electrical stimulation-induced (ES; 60â Hz) DA release was recorded in the NAc of single- or pair-housed male and female rats. When core (NAcC) and shell (NAcS) were recorded simultaneously, there was greater ES DA release in NAcC of pair-housed females compared with single females and males. Housing did not affect ES NAc DA release in males. In contrast, there was significantly more ES DA release from the DLS of female rats than male rats. This was true prior to and after treatment with methamphetamine. Furthermore, in castrated (CAST) males and ovariectomized (OVX) females, there were no sex differences in ES DA release from the DLS, demonstrating the hormone dependence of this sex difference. However, in the DLS of both intact and gonadectomized rats, DA reuptake was slower in females than that in males. Finally, DA release following ES of the medial forebrain bundle at 60â Hz was studied over 4â weeks. ES DA release increased over time for both CAST males and OVX females, demonstrating sensitization. Using this novel 16-channel chronic FSCV electrode, we found sex differences in the effects of social housing in the NAcS, sex differences in DA release from intact rats in DLS, and sex differences in DA reuptake in DLS of intake and gonadectomized rats, and we report sensitization of ES-induced DA release in DLS in vivo.
Assuntos
Corpo Estriado , Dopamina , Estimulação Elétrica , Núcleo Accumbens , Caracteres Sexuais , Animais , Masculino , Núcleo Accumbens/metabolismo , Feminino , Dopamina/metabolismo , Ratos , Corpo Estriado/metabolismo , Estimulação Elétrica/métodos , Ratos Sprague-Dawley , Abrigo para Animais , Ovariectomia , Metanfetamina/farmacologiaRESUMO
Cerebellum has been implicated in drug addiction; however, its underlying cellular populations and neuronal circuitry remain largely unknown. In the current study, we identified a neural pathway from tyrosine hydroxylase (TH)-positive Purkinje cells (PCTH+) in cerebellar lobule VI to calcium/calmodulin-dependent protein kinase II (CaMKII)-positive glutamatergic neurons in the medial cerebellar nucleus (MedCaMKII), forming the lobule VI PCTH+-MedCaMKII pathway in male mice. In naive male mice, inhibition of PCTH+ neurons activated Med neurons. During conditioned place preference (CPP) training, exposure to methamphetamine (METH) inhibited lobule VI PCTH+ neurons while excited MedCaMKII neurons in mice. Silencing MedCaMKII using a tetanus toxin light chain (tettox) suppressed the acquisition of METH CPP in mice but resulted in motor coordination deficits in naive mice. In contrast, activating lobule VI PCTH+ terminals within Med inhibited the activity of Med neurons and subsequently blocked the acquisition of METH CPP in mice without affecting motor coordination, locomotor activity, and sucrose reinforcements in naive mice. Our findings identified a novel lobule VI PCTH+-MedCaMKII pathway within the cerebellum and explored its role in mediating the acquisition of METH-preferred behaviors.
Assuntos
Estimulantes do Sistema Nervoso Central , Metanfetamina , Animais , Masculino , Camundongos , Metanfetamina/farmacologia , Tirosina 3-Mono-Oxigenase/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Reforço Psicológico , Cerebelo/metabolismo , Estimulantes do Sistema Nervoso Central/farmacologiaRESUMO
Anxiety is one of the most common withdrawal symptoms of methamphetamine (METH) abuse, which further drives relapse to drugs. Interpeduncular nucleus (IPN) has been implicated in anxiety-like behaviors and addiction, yet its role in METH-abstinence-induced anxiety remains unknown. Here, we found that prolonged abstinence from METH enhanced anxiety-like behaviors in male mice, accompanied by more excited IPN GABAergic neurons, as indicated by the increased c-fos expression and the enhanced neuronal excitability by electrophysiological recording in the GABAergic neurons. Using the designer receptors exclusively activated by designer drugs method, specific inhibition of IPN GABAergic neurons rescued the aberrant neuronal excitation of IPN GABAergic neurons and efficiently reduced anxiety-like behaviors, whereas it did not induce depression-like behaviors in male mice after prolonged abstinence from METH. These findings reveal that IPN GABAergic neurons should be a promising brain target to alleviate late withdrawal symptoms from METH with few side effects.SIGNIFICANCE STATEMENT Prolonged abstinence from METH triggers IPN GABAergic neurons and ultimately increases anxiety in male mice. Suppressing IPN GABAergic neurons rescues METH abstinence-induced aberrant neuronal excitation of IPN GABAergic neurons and efficiently reduces anxiety in mice.
Assuntos
Transtornos Relacionados ao Uso de Anfetaminas , Núcleo Interpeduncular , Metanfetamina , Síndrome de Abstinência a Substâncias , Camundongos , Masculino , Animais , Metanfetamina/farmacologia , Núcleo Interpeduncular/metabolismo , Ansiedade/metabolismo , Neurônios GABAérgicos/metabolismo , Síndrome de Abstinência a Substâncias/metabolismo , Transtornos Relacionados ao Uso de Anfetaminas/metabolismoRESUMO
Methamphetamine (Meth) use is known to induce complex neuroinflammatory responses, particularly involving astrocytes and microglia. Building upon our previous research, which demonstrated that Meth stimulates astrocytes to release tumor necrosis factor (TNF) and glutamate, leading to microglial activation, this study investigates the role of the anti-inflammatory cytokine interleukin-10 (IL-10) in this process. Our findings reveal that the presence of recombinant IL-10 (rIL-10) counteracts Meth-induced excessive glutamate release in astrocyte cultures, which significantly reduces microglial activation. This reduction is associated with the modulation of astrocytic intracellular calcium (Ca2+) dynamics, particularly by restricting the release of Ca2+ from the endoplasmic reticulum to the cytoplasm. Furthermore, we identify the small Rho GTPase Cdc42 as a crucial intermediary in the astrocyte-to-microglia communication pathway under Meth exposure. By employing a transgenic mouse model that overexpresses IL-10 (pMT-10), we also demonstrate in vivo that IL-10 prevents Meth-induced neuroinflammation. These findings not only enhance our understanding of Meth-related neuroinflammatory mechanisms, but also suggest IL-10 and Cdc42 as putative therapeutic targets for treating Meth-induced neuroinflammation.
Assuntos
Astrócitos , Interleucina-10 , Metanfetamina , Camundongos Transgênicos , Microglia , Proteína cdc42 de Ligação ao GTP , Animais , Metanfetamina/toxicidade , Metanfetamina/farmacologia , Interleucina-10/metabolismo , Interleucina-10/farmacologia , Astrócitos/metabolismo , Astrócitos/efeitos dos fármacos , Proteína cdc42 de Ligação ao GTP/metabolismo , Microglia/efeitos dos fármacos , Microglia/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Estimulantes do Sistema Nervoso Central/toxicidade , Estimulantes do Sistema Nervoso Central/farmacologia , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/induzido quimicamente , Células Cultivadas , Ácido Glutâmico/metabolismo , Ácido Glutâmico/toxicidadeRESUMO
The 3,4-methylenedioxymethamphetamine (MDMA) has long been used non-medically, and it is currently under investigation for its potential therapeutic benefits. Both uses may be related to its ability to enhance empathy, sociability, emotional processing and its anxiolytic effects. However, the neural mechanisms underlying these effects, and their specificity to MDMA compared to other stimulants, are not yet fully understood. Here, using electroencephalography (EEG), we investigated the effects of MDMA and a prototypic stimulant, methamphetamine (MA), on early visual processing of socio-emotional stimuli in an oddball emotional faces paradigm. Specifically, we examined whether MDMA or MA enhance the processing of facial expressions, compared to placebo, during the early stages of visual perception. MDMA enhanced an event-related component that is sensitive to detecting faces (N170), specifically for happy and angry expressions compared to neutral faces. MA did not affect this measure, and neither drug altered other components of the response to emotional faces. These findings provide novel insights into the neural mechanisms underlying the effects of MDMA on socio-emotional processing and may have implications for the therapeutic use of MDMA in the treatment of social anxiety and other psychiatric disorders.
Assuntos
Emoções , Expressão Facial , N-Metil-3,4-Metilenodioxianfetamina , Adulto , Feminino , Humanos , Masculino , Adulto Jovem , Estimulantes do Sistema Nervoso Central/farmacologia , Eletroencefalografia/métodos , Emoções/efeitos dos fármacos , Emoções/fisiologia , Reconhecimento Facial/efeitos dos fármacos , Reconhecimento Facial/fisiologia , Alucinógenos/farmacologia , Metanfetamina/farmacologia , N-Metil-3,4-Metilenodioxianfetamina/farmacologia , N-Metil-3,4-Metilenodioxianfetamina/administração & dosagem , Percepção Visual/efeitos dos fármacos , Percepção Visual/fisiologia , Método Duplo-CegoRESUMO
The number of drug overdoses and deaths has increased significantly over the past decade and co-use of opioids and stimulants is associated with greater likelihood of overdose and decreased likelihood of accessing treatment, compared with use of opioids alone. Potential adverse effects of opioid/stimulant mixtures, particularly methamphetamine, are not well characterized. Two structurally different drugs with agonist properties at µ-opioid receptors (MOR), fentanyl and heroin, and d-methamphetamine, alone and in mixtures, were assessed for their effects on ventilation in rats breathing normal air. Whole-body phethysmography chambers were equipped with a tower and swivel allowing infusions to indwelling intravenous catheters. After a 45-minute habituation period, saline, fentanyl, heroin, or d-methamphetamine, alone and in mixtures, was administered. Five minutes later, the opioid receptor antagonist naloxone or vehicle was injected. Fentanyl (0.0032-0.1 mg/kg) and heroin (0.32-3.2 mg/kg) decreased ventilation [frequency (f) and tidal volume (VT)] in a dose-related manner whereas d-methamphetamine (0.1-3.2 mg/kg) increased f to >400% of control and decreased VT to <60% of control, overall increasing minute volume (product of f and VT) to >240% of control. When combined, d-methamphetamine (0.1-3.2 mg/kg) attenuated the ventilatory depressant effects of fentanyl (0.1 mg/kg) and heroin (3.2 mg/kg). d-Methamphetamine did not alter the potency of naloxone to reverse the ventilatory depressant effects of fentanyl or heroin. These studies demonstrate that d-methamphetamine can attenuate the ventilatory depressant effects of moderate doses of opioid receptor agonists while not altering the potency of naloxone to reverse opioid hypoventilation. SIGNIFICANCE STATEMENT: Co-use of opioids and stimulants is associated with greater likelihood of overdose and decreased likelihood of accessing treatment, compared with use of opioids alone. Potential adverse effects of opioid/stimulant mixtures are not well characterized. This study reports that 1) d-methamphetamine attenuates the ventilatory depressant effects of moderate doses of two structurally different opioid receptor agonists, fentanyl and heroin, and 2) d-methamphetamine does not alter potency or effectiveness of naloxone to reverse the ventilatory depressant effects of these opioid receptor agonists.
Assuntos
Overdose de Drogas , Metanfetamina , Masculino , Animais , Ratos , Heroína/farmacologia , Fentanila/efeitos adversos , Analgésicos Opioides/efeitos adversos , Metanfetamina/farmacologia , Naloxona , Overdose de Drogas/tratamento farmacológico , Receptores OpioidesRESUMO
Methamphetamine (MA) is a highly addictive mental stimulant, and MA abuse remains a significant public health problem worldwide, while effective treatment options are limited. Lycium barbarum polysaccharide (LBP), a major effective component extracted from Lycium barbarum, has potential health-promoting effects on the nervous system; however, its role in MA dependence remains unclear. In this study, the conditioned place preference (CPP) of MA addiction in adult male mice was established to detect changes in gut microbiota profiles after LBP treatment through 16S rRNA gene sequencing. Our results found that LBP administration could alleviate MA-induced CPP and hyperactivity. Interestingly, LBP improved MA-induced gut microbiota dysbiosis by increasing some beneficial autochthonous genus abundances, such as Allobaculum, Gordonibacter, and Ileibacterium. MA exposure induced the co-occurrence network of intestinal microbiota to become weaker and more unstable when compared with the control group, while LBP changed the above effects when compared with the MA group. Bacterial gene function prediction showed that amphetamine addiction, cocaine addiction, and short-chain fatty acid metabolism were enriched. These findings reveal that LBP might regulate MA-induced gut microbiota and behavior changes, which showed potential therapeutic applicability in treating MA addiction by regulating the gut microbiota.
Assuntos
Transtornos Relacionados ao Uso de Anfetaminas , Medicamentos de Ervas Chinesas , Disbiose , Microbioma Gastrointestinal , Metanfetamina , Animais , Microbioma Gastrointestinal/efeitos dos fármacos , Metanfetamina/farmacologia , Disbiose/induzido quimicamente , Disbiose/microbiologia , Masculino , Camundongos , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/administração & dosagem , RNA Ribossômico 16S/análise , Camundongos Endogâmicos C57BL , Bactérias/efeitos dos fármacos , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/genéticaRESUMO
It is widely believed that the activation of the central dopamine (DA) system is crucial to the rewarding effects of methamphetamine (METH) and to the behavioral outcomes of METH use disorder. It was reported that METH exposure induced gasdermin D (GSDMD)-dependent pyroptosis in rats. The membrane pore formation caused by METH-induced pyroptosis may also contribute to the overflow of DA into the extracellular space and subsequently increase the DA levels in the brain. The present study firstly investigated whether the membrane pore information induced by GSDMD-dependent pyroptosis was associated with the increased DA levels in the ventral tegmental area (VAT) and nucleus accumbens (NAc) of rats self-administering METH and SY-SH5Y cells treated by METH. Subsequently, the effect of pore formation blockade or genetic inhibition of GSDMD on the reinforcing and motivational effect of METH was determined in rats, using the animal model of METH self-administration (SA). METH exposure significantly increased the activity of NLRP1/Cas-1/GSDMD pathway and the presence of pyroptosis, accompanied by the significantly increased DA levels in VTA and NAc. Moreover, intraperitoneal injections of disulfiram (DSF) or microinjection of rAAV-shGSDMD into VTA/NAc significantly reduced the reinforcing and motivational effect of METH, accompanied by the decreased level of DA in VTA and NAc. The results provided novel evidence that METH-induced pyroptosis could increase DA release in VTA and NAc via the NLRP1/Cas-1/GSDMD pathway. Additionally, membrane pores or GSDMD blockade could significantly reduce the reinforcing and motivational effect of METH. In conclusion, blocking GSDMD and membrane pore formation could be a promising potential target for the development of agents to treat METH use disorder.
Assuntos
Dopamina , Metanfetamina , Núcleo Accumbens , Proteínas de Ligação a Fosfato , Piroptose , Autoadministração , Área Tegmentar Ventral , Animais , Metanfetamina/farmacologia , Metanfetamina/administração & dosagem , Piroptose/efeitos dos fármacos , Masculino , Proteínas de Ligação a Fosfato/metabolismo , Ratos , Núcleo Accumbens/metabolismo , Núcleo Accumbens/efeitos dos fármacos , Dopamina/metabolismo , Área Tegmentar Ventral/metabolismo , Área Tegmentar Ventral/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Ratos Sprague-Dawley , Humanos , Estimulantes do Sistema Nervoso Central/farmacologia , Estimulantes do Sistema Nervoso Central/administração & dosagem , GasderminasRESUMO
Methamphetamine use disorder (MUD) is a chronic, relapsing disease that is characterized by repeated drug use despite negative consequences and for which there are currently no FDA-approved cessation therapeutics. Repeated methamphetamine (METH) use induces long-term gene expression changes in brain regions associated with reward processing and drug-seeking behavior, and recent evidence suggests that methamphetamine-induced neuroinflammation may also shape behavioral and molecular responses to the drug. Microglia, the resident immune cells in the brain, are principal drivers of neuroinflammatory responses and contribute to the pathophysiology of substance use disorders. Here, we investigated transcriptional and morphological changes in dorsal striatal microglia in response to methamphetamine-taking and during methamphetamine abstinence, as well as their functional contribution to drug-taking behavior. We show that methamphetamine self-administration induces transcriptional changes associated with protein folding, mRNA processing, immune signaling, and neurotransmission in dorsal striatal microglia. Importantly, many of these transcriptional changes persist through abstinence, a finding supported by morphological analyses. Functionally, we report that microglial ablation increases methamphetamine-taking, possibly involving neuroimmune and neurotransmitter regulation. In contrast, microglial depletion during abstinence does not alter methamphetamine-seeking. Taken together, these results suggest that methamphetamine induces both short and long-term changes in dorsal striatal microglia that contribute to altered drug-taking behavior and may provide valuable insights into the pathophysiology of MUD.
Assuntos
Transtornos Relacionados ao Uso de Anfetaminas , Comportamento de Procura de Droga , Metanfetamina , Microglia , Autoadministração , Metanfetamina/farmacologia , Microglia/metabolismo , Microglia/efeitos dos fármacos , Animais , Masculino , Comportamento de Procura de Droga/efeitos dos fármacos , Comportamento de Procura de Droga/fisiologia , Camundongos , Transtornos Relacionados ao Uso de Anfetaminas/metabolismo , Estimulantes do Sistema Nervoso Central/farmacologia , Corpo Estriado/metabolismo , Corpo Estriado/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Reforço Psicológico , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacosRESUMO
BACKGROUND: Treatment of refractory bipolar disorder (BD) is extremely challenging. Deep brain stimulation (DBS) holds promise as an effective treatment intervention. However, we still understand very little about the mechanisms of DBS and its application on BD. AIM: The present study aimed to investigate the behavioural and neurochemical effects of ventral tegmental area (VTA) DBS in an animal model of mania induced by methamphetamine (m-amph). METHODS: Wistar rats were given 14 days of m-amph injections, and on the last day, animals were submitted to 20 min of VTA DBS in two different patterns: intermittent low-frequency stimulation (LFS) or continuous high-frequency stimulation (HFS). Immediately after DBS, manic-like behaviour and nucleus accumbens (NAc) phasic dopamine (DA) release were evaluated in different groups of animals through open-field tests and fast-scan cyclic voltammetry. Levels of NAc dopaminergic markers were evaluated by immunohistochemistry. RESULTS: M-amph induced hyperlocomotion in the animals and both DBS parameters reversed this alteration. M-amph increased DA reuptake time post-sham compared to baseline levels, and both LFS and HFS were able to block this alteration. LFS was also able to reduce phasic DA release when compared to baseline. LFS was able to increase dopamine transporter (DAT) expression in the NAc. CONCLUSION: These results demonstrate that both VTA LFS and HFS DBS exert anti-manic effects and modulation of DA dynamics in the NAc. More specifically the increase in DA reuptake driven by increased DAT expression may serve as a potential mechanism by which VTA DBS exerts its anti-manic effects.
Assuntos
Estimulação Encefálica Profunda , Modelos Animais de Doenças , Mania , Metanfetamina , Ratos Wistar , Área Tegmentar Ventral , Animais , Área Tegmentar Ventral/efeitos dos fármacos , Área Tegmentar Ventral/metabolismo , Metanfetamina/farmacologia , Masculino , Ratos , Mania/terapia , Mania/induzido quimicamente , Estimulantes do Sistema Nervoso Central/farmacologia , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Dopamina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Transtorno Bipolar/terapia , Transtorno Bipolar/induzido quimicamenteRESUMO
Methamphetamine (METH) produces a cytopathology, which is rather specific within catecholamine neurons both in vitro and ex vivo, in animal models and chronic METH abusers. This led some authors to postulate a sort of parallelism between METH cytopathology and cell damage in Parkinson's disease (PD). In fact, METH increases and aggregates alpha-syn proto-fibrils along with producing spreading of alpha-syn. Although alpha-syn is considered to be the major component of aggregates and inclusions developing within diseased catecholamine neurons including classic Lewy body (LB), at present, no study provided a quantitative assessment of this protein in situ, neither following METH nor in LB occurring in PD. Similarly, no study addressed the quantitative comparison between occurrence of alpha-syn and other key proteins and no investigation measured the protein compared with non-protein structure within catecholamine cytopathology. Therefore, the present study addresses these issues using an oversimplified model consisting of a catecholamine cell line where the novel approach of combined light and electron microscopy (CLEM) was used measuring the amount of alpha-syn, which is lower compared with p62 or poly-ubiquitin within pathological cell domains. The scenario provided by electron microscopy reveals unexpected findings, which are similar to those recently described in the pathology of PD featuring packing of autophagosome-like vesicles and key proteins shuttling autophagy substrates. Remarkably, small seed-like areas, densely packed with p62 molecules attached to poly-ubiquitin within wide vesicular domains occurred. The present data shed new light about quantitative morphometry of catecholamine cell damage in PD and within the addicted brain.
Assuntos
Metanfetamina , Doença de Parkinson , Animais , Metanfetamina/farmacologia , alfa-Sinucleína/metabolismo , Doença de Parkinson/metabolismo , Microscopia Eletrônica , Catecolaminas , UbiquitinasRESUMO
N-Isopropylbenzylamine (N-ipb), a chain isomer of methamphetamine (METH) with similar physical properties, has been used as a substitute for METH in seized drug samples. However, the abuse potential of N-ipb remains unclear. Therefore, this study aimed to evaluate the abuse potential of N-ipb in comparison to METH, by using conditioned place preference (CPP), locomotor sensitization and intravenous self-administration tests. The results showed that N-ipb at a dose of 3 mg·kg-1 significantly induced CPP in mice, which was comparable to the effect of METH at 1 mg·kg-1 . Either acute or repeated N-ipb injections (1 or 3 mg·kg-1 ) failed to raise the locomotor activity. However, acute treatment with 10 mg·kg-1 N-ipb elevated the locomotor activity compared with saline, while chronic injection of 10 mg·kg-1 N-ipb induced a delayed and attenuated sensitization compared with 1 mg·kg-1 METH. Rats could acquire N-ipb self-administration at a dose of 1 mg·kg-1 ·infusion-1 , and a typical inverted U-shaped dose-response curve was obtained for N-ipb. The mean dose of N-ipb that maintained the maximum response was greater than that of METH, indicating that N-ipb is less potent for reinforcement than METH. In the economic behavioural analysis, comparison of essential values derived from the demand elasticity revealed that N-ipb is less efficacy as a reinforcer than METH. The present data demonstrate that N-ipb functions as a reinforcer and has a potential for abuse. However, the potency of psychomotor stimulation and the reinforcing effectiveness of N-ipb are lower than those of METH.
Assuntos
Aminas , Estimulantes do Sistema Nervoso Central , Metanfetamina , Camundongos , Ratos , Animais , Estimulantes do Sistema Nervoso Central/farmacologia , Roedores , Atividade Motora , Metanfetamina/farmacologiaRESUMO
Methamphetamine (METH) is a highly addictive psycho-stimulant that induces addictive behaviour by stimulating increased dopamine release in the nucleus accumbens (NAc). The sarco/endoplasmic reticulum calcium ion transport ATPases (SERCA or ATP2A) is a calcium ion (Ca2+) pump in the endoplasmic reticulum (ER) membrane. SERCA2b is a SERCA subtype mainly distributed in the central nervous system. This study used conditioned place preference (CPP), a translational drug reward model, to observe the effects of SERCA and SERCA2b on METH-CPP in mice. Result suggested that the activity of SERCA was significantly decreased in NAc after METH-CPP. Intraperitoneal SERCA agonist CDN1163 injection or bilateral CDN1163 microinjection in the NAc inhibited METH-CPP formation. SERCA2b overexpression by the Adeno-associated virus can reduce the DA release of NAc and inhibit METH-CPP formation. Although microinjection of SERCA inhibitor thapsigargin in the bilateral NAc did not significantly aggravate METH-CPP, interference with SERCA2b expression in NAc by adeno-associated virus increased DA release and promoted METH-CPP formation. METH reduced the SERCA ability to transport Ca2+ into the ER in SHSY5Y cells in vitro, which was reversed by CDN1163. This study revealed that METH dysregulates intracellular calcium balance by downregulating SERCA2b function, increasing DA release in NAc and inducing METH-CPP formation. Drugs that target SERCA2b may have the potential to treat METH addiction.
Assuntos
Benzamidas , Estimulantes do Sistema Nervoso Central , Metanfetamina , Camundongos , Animais , Metanfetamina/farmacologia , Metanfetamina/metabolismo , Núcleo Accumbens , Cálcio/metabolismo , Aminoquinolinas/metabolismo , Aminoquinolinas/farmacologia , Estimulantes do Sistema Nervoso Central/farmacologia , Estimulantes do Sistema Nervoso Central/metabolismoRESUMO
We used Drosophila melanogaster to map the genetic basis of naturally occurring variation in voluntary consumption of cocaine and methamphetamine. We derived an outbred advanced intercross population (AIP) from 37 sequenced inbred wild-derived lines of the Drosophila melanogaster Genetic Reference Panel (DGRP), which are maximally genetically divergent, have minimal residual heterozygosity, are not segregating for common inversions, and are not infected with Wolbachia pipientis We assessed consumption of sucrose, methamphetamine-supplemented sucrose, and cocaine-supplemented sucrose and found considerable phenotypic variation for consumption of both drugs, in both sexes. We performed whole-genome sequencing and extreme quantitative trait locus (QTL) mapping on the top 10% of consumers for each replicate, sex, and condition and an equal number of randomly selected flies. We evaluated changes in allele frequencies among high consumers and control flies and identified 3,033 variants significantly (P < 1.9 × 10-8) associated with increased consumption, located in or near 1,962 genes. Many of these genes are associated with nervous system development and function, and 77 belong to a known gene-gene interaction subnetwork. We assessed the effects of RNA interference (RNAi) on drug consumption for 22 candidate genes; 17 had a significant effect in at least one sex. We constructed allele-specific AIPs that were homozygous for alternative candidate alleles for 10 single-nucleotide polymorphisms (SNPs) and measured average consumption for each population; 9 SNPs had significant effects in at least one sex. The genetic basis of voluntary drug consumption in Drosophila is polygenic and implicates genes with human orthologs and associated variants with sex- and drug-specific effects.
Assuntos
Cocaína/farmacologia , Proteínas de Drosophila/genética , Epistasia Genética , Metanfetamina/farmacologia , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Caracteres Sexuais , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Feminino , Estudo de Associação Genômica Ampla , Humanos , MasculinoRESUMO
The detailed mechanisms by which dopamine (DA) and serotonin (5-HT) act in the nucleus accumbens (NAc) to influence motivated behaviors in distinct ways remain largely unknown. Here, we examined whether DA and 5-HT selectively modulate excitatory synaptic transmission in NAc medium spiny neurons in an input-specific manner. DA reduced excitatory postsynaptic currents (EPSCs) generated by paraventricular thalamus (PVT) inputs but not by ventral hippocampus (vHip), basolateral amygdala (BLA), or medial prefrontal cortex (mPFC) inputs. In contrast, 5-HT reduced EPSCs generated by inputs from all areas except the mPFC. Release of endogenous DA and 5-HT by methamphetamine (METH) and (±)3,4-methylenedioxymethamphetamine (MDMA), respectively, recapitulated these input-specific synaptic effects. Optogenetic inhibition of PVT inputs enhanced cocaine-conditioned place preference, whereas mPFC input inhibition reduced the enhancement of sociability elicited by MDMA. These findings suggest that the distinct, input-specific filtering of excitatory inputs in the NAc by DA and 5-HT contribute to their discrete behavioral effects.
Assuntos
Dopamina/farmacologia , Potenciais Pós-Sinápticos Excitadores , Núcleo Accumbens/fisiologia , Serotonina/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Metanfetamina/farmacologia , Camundongos Endogâmicos C57BL , N-Metil-3,4-Metilenodioxianfetamina/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Núcleo Accumbens/efeitos dos fármacos , Interação Social/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacosRESUMO
Methamphetamine (METH) abuse inflicts both physical and psychological harm. While our previous research has established the regulatory role of miR-29c-3p in behavior sensitization, the underlying mechanisms and target genes remain incompletely understood. In this study, we employed the isobaric tags for relative and absolute quantitation (iTRAQ) technique in conjunction with Ingenuity pathway analysis (IPA) to probe the putative molecular mechanisms of METH sensitization through miR-29c-3p inhibition. Through a microinjection of AAV-anti-miR-29c-3p into the nucleus accumbens (NAc) of mice, we observed the attenuation of METH-induced locomotor effects. Subsequent iTRAQ analysis identified 70 differentially expressed proteins (DEPs), with 22 up-regulated potential target proteins identified through miR-29c-3p target gene prediction and IPA analysis. Our focus extended to the number of neuronal branches, the excitatory synapse count, and locomotion-related pathways. Notably, GPR37, NPC1, and IREB2 emerged as potential target molecules for miR-29c-3p regulation, suggesting their involvement in the modulation of METH sensitization. Quantitative PCR confirmed the METH-induced aberrant expression of Gpr37, Npc1, and Ireb2 in the NAc of mice. Specifically, the over-expression of miR-29c-3p led to a significant reduction in the mRNA level of Gpr37, while the inhibition of miR-29c-3p resulted in a significant increase in the mRNA level of Gpr37, consistent with the regulatory principle of miRNAs modulating target gene expression. This suggests that miR-29c-3p potentially influences METH sensitization through its regulation of neuroplasticity. Our research indicates that miR-29c-3p plays a crucial role in regulating METH-induced sensitization, and it identified the potential molecular of miR-29c-3p in regulating METH-induced sensitization.
Assuntos
Transtornos Relacionados ao Uso de Anfetaminas , Metanfetamina , MicroRNAs , Doença de Niemann-Pick Tipo C , Animais , Camundongos , Núcleo Accumbens , Metanfetamina/farmacologia , MicroRNAs/genética , Plasticidade Neuronal/genética , RNA Mensageiro , Receptores Acoplados a Proteínas GRESUMO
The orbitofrontal cortex (OFC)-dorsal striatum (DS) is an important neural circuit that contributes to addictive behavior, including compulsive reinforcement, yet the specific types of neurons that play a major role still need to be further elucidated. Here, we used a place conditioning paradigm to measure the conditioned responses to methamphetamine (MA). The results demonstrated that MA increases the expression of c-Fos, synaptic plasticity in OFC and DS. Patch-clamp recording showed that MA activated projection neurons from the OFC to the DS, and chemogenetic manipulation of neuronal activity in OFC-DS projection neurons affects conditioned place preference (CPP) scores. And the combined patch-electrochemical technique was used to detect the DA release in OFC, the data indicated that the DA release was increased in MA group. Additionally, SCH23390, a D1R antagonist, was used to verify the function of D1R projection neurons, showing that SCH23390 reversed MA addiction-like behavior. Collectively, these findings provide evidence for the D1R neuron is sufficient to regulate MA addiction in the OFC-DS pathway, and the study provides new insight into the underlying mechanism of pathological changes in MA addiction.
Assuntos
Corpo Estriado , Metanfetamina , Corpo Estriado/metabolismo , Córtex Pré-Frontal/metabolismo , Metanfetamina/farmacologia , Neurônios/metabolismo , Receptores de Dopamina D1/metabolismoRESUMO
Synthetic cathinones are a class of new psychoactive substances that display psychomotor stimulant properties, and novel cathinone analogs continue to emerge in illicit drug markets worldwide. The aim of the present study was to characterize the pharmacology of 4-chloro ring-substituted cathinones that are appearing in illicit drug markets compared with the effects of 4-methylmethcathinone (mephedrone). Synaptosomes were prepared from rat caudate for dopamine transporter (DAT) assays or from whole brain minus caudate and cerebellum for norepinephrine transporter (NET) and serotonin transporter (SERT) assays. Findings from transporter uptake inhibition and release assays showed that mephedrone and 4-chloromethcathinone (4-CMC) function as substrates at DAT, NET, and SERT, with similar potency at all three transporters. In contrast, 4-chloro-α-pyrrolidinopropiophenone (4-CαPPP) was an uptake inhibitor at DAT and NET, with similar potency at each site, but had little activity at SERT. 4-Chloroethcathinone (4-CEC) was a low-potency uptake inhibitor at DAT and NET but a substrate at SERT. In rats implanted with telemetry transmitters, mephedrone and 4-CMC increased blood pressure, heart rate, and locomotor activity to a similar extent. 4-CEC and 4-CαPPP were less potent at increasing blood pressure and had modest stimulatory effects on heart rate and activity. 4-CMC also transiently decreased temperature at the highest dose tested. All three 4-chloro ring-substituted cathinones are biologically active, but only 4-CMC has potency comparable to mephedrone. Collectively, our findings suggest that 4-CMC and other 4-chloro cathinones may have abuse potential and adverse effects in humans that are analogous to those associated with mephedrone. SIGNIFICANCE STATEMENT: The 4-chloro ring-substituted cathinones all produced significant cardiovascular stimulation, with 4-chloromethcathinone (4-CMC) showing potency similar to mephedrone. All of the drugs are likely to be abused given their effects at the dopamine transporter, particularly 4-CMC.