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Small molecule neurotensin receptor 1 (NTSR1) agonists have been pursued for more than 40 years as potential therapeutics for psychiatric disorders, including drug addiction. Clinical development of NTSR1 agonists has, however, been precluded by their severe side effects. NTSR1, a G protein-coupled receptor (GPCR), signals through the canonical activation of G proteins and engages ß-arrestins to mediate distinct cellular signaling events. Here, we characterize the allosteric NTSR1 modulator SBI-553. This small molecule not only acts as a ß-arrestin-biased agonist but also extends profound ß-arrestin bias to the endogenous ligand by selectively antagonizing G protein signaling. SBI-553 shows efficacy in animal models of psychostimulant abuse, including cocaine self-administration, without the side effects characteristic of balanced NTSR1 agonism. These findings indicate that NTSR1 G protein and ß-arrestin activation produce discrete and separable physiological effects, thus providing a strategy to develop safer GPCR-targeting therapeutics with more directed pharmacological action.
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Comportamento Aditivo/metabolismo , Receptores de Neurotensina/metabolismo , beta-Arrestinas/metabolismo , Regulação Alostérica/efeitos dos fármacos , Regulação Alostérica/fisiologia , Animais , Comportamento Aditivo/tratamento farmacológico , Linhagem Celular , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Animais , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Bibliotecas de Moléculas Pequenas/farmacologiaRESUMO
Electronic nicotine delivery systems (ENDS) are distinctly different from combustible cigarettes because of the availability of flavor options. Subjective measures have been used to demonstrate that adults and adolescents prefer flavors for various reasons; (1) they are pleasing and (2) they mask the harshness of nicotine. Despite this, there have been few investigations into the molecular interactions that connect chemical flavorants to smoking or vaping-related behaviors. Here, we investigated the effects of three chemical flavorants (hexyl acetate, ethyl acetate, and methylbutyl acetate) that are found in green apple (GA) ENDS e-liquids but are also found in other flavor categories. We used a translationally relevant vapor self-administration mouse model and observed that adult male and female mice self-administered GA flavorants in the absence of nicotine. Using α4-mCherryα6-GFP nicotinic acetylcholine receptor (nAChR) mice, we observed that mice exposed to GA flavorants exhibited a sex-specific increase (upregulation) of nAChRs that was also brain-region specific. Electrophysiology revealed that mice exposed to GA flavorants exhibited enhanced firing of ventral tegmental area dopamine neurons. Fast-scan cyclic voltammetry revealed that electrically stimulated dopamine release in the nucleus accumbens core is increased in mice that are exposed to GA flavorants. These effects were similarly observed in the medial habenula. Overall, these findings demonstrate that ENDS flavors alone change neurobiology and may promote vaping-dependent behaviors in the absence of nicotine. Furthermore, the flavorant-induced changes in neurobiology parallel those caused by nicotine, which highlights the fact that nonmenthol flavorants may contribute to or enhance nicotine reward and reinforcement.SIGNIFICANCE STATEMENT The impact of flavors on vaping is a hotly debated topic; however, few investigations have examined this in a model that is relevant to vaping. Although a full understanding of the exact mechanism remains undetermined, our observations reveal that chemical flavorants in the absence of nicotine alter brain circuits relevant to vaping-related behavior. The fact that the flavorants investigated here exist in multiple flavor categories of vaping products highlights the fact that a multitude of flavored vaping products may pose a risk toward vaping-dependent behaviors even without the impact of nicotine. Furthermore, as the neurobiological changes have an impact on neurons of the reward system, there exists the possibility that nonmenthol flavorants may enhance nicotine reward and reinforcement.
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Receptores Nicotínicos , Produtos do Tabaco , Vaping , Masculino , Feminino , Camundongos , Animais , Nicotina/farmacologia , Neurobiologia , Reforço PsicológicoRESUMO
The brain µ-opioid receptor (MOR) is critical for the analgesic, rewarding, and addictive effects of opioid drugs. However, in rat models of opioid-related behaviors, the circuit mechanisms of MOR-expressing cells are less known because of a lack of genetic tools to selectively manipulate them. We introduce a CRISPR-based Oprm1-Cre knock-in transgenic rat that provides cell type-specific genetic access to MOR-expressing cells. After performing anatomic and behavioral validation experiments, we used the Oprm1-Cre knock-in rats to study the involvement of NAc MOR-expressing cells in heroin self-administration in male and female rats. Using RNAscope, autoradiography, and FISH chain reaction (HCR-FISH), we found no differences in Oprm1 expression in NAc, dorsal striatum, and dorsal hippocampus, or MOR receptor density (except dorsal striatum) or function between Oprm1-Cre knock-in rats and wildtype littermates. HCR-FISH assay showed that iCre is highly coexpressed with Oprm1 (95%-98%). There were no genotype differences in pain responses, morphine analgesia and tolerance, heroin self-administration, and relapse-related behaviors. We used the Cre-dependent vector AAV1-EF1a-Flex-taCasp3-TEVP to lesion NAc MOR-expressing cells. We found that the lesions decreased acquisition of heroin self-administration in male Oprm1-Cre rats and had a stronger inhibitory effect on the effort to self-administer heroin in female Oprm1-Cre rats. The validation of an Oprm1-Cre knock-in rat enables new strategies for understanding the role of MOR-expressing cells in rat models of opioid addiction, pain-related behaviors, and other opioid-mediated functions. Our initial mechanistic study indicates that lesioning NAc MOR-expressing cells had different effects on heroin self-administration in male and female rats.SIGNIFICANCE STATEMENT The brain µ-opioid receptor (MOR) is critical for the analgesic, rewarding, and addictive effects of opioid drugs. However, in rat models of opioid-related behaviors, the circuit mechanisms of MOR-expressing cells are less known because of a lack of genetic tools to selectively manipulate them. We introduce a CRISPR-based Oprm1-Cre knock-in transgenic rat that provides cell type-specific genetic access to brain MOR-expressing cells. After performing anatomical and behavioral validation experiments, we used the Oprm1-Cre knock-in rats to show that lesioning NAc MOR-expressing cells had different effects on heroin self-administration in males and females. The new Oprm1-Cre rats can be used to study the role of brain MOR-expressing cells in animal models of opioid addiction, pain-related behaviors, and other opioid-mediated functions.
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Dependência de Heroína , Heroína , Ratos , Masculino , Feminino , Animais , Heroína/farmacologia , Analgésicos Opioides/farmacologia , Núcleo Accumbens , Receptores Opioides/metabolismo , Ratos Transgênicos , Receptores Opioides mu/genética , Receptores Opioides mu/metabolismo , Dor/metabolismoRESUMO
The prevalence of opioid use disorder and overdose continues to harm the U.S. population and is further exacerbated by the use of the synthetic opioid, fentanyl, and its analogs. Gender differences in the effects of fentanyl are not well understood. The present article reviews evidence for gender and sex differences in the physiological and behavioral effects of fentanyl in humans and animals. Biological sex seems to be a foundational driver in addiction vulnerability and affects mechanisms related to opioid use including fentanyl. Fentanyl has distinct pharmacodynamics and enhanced efficacy relative to other opioids that highlights the need to investigate how females may be uniquely altered by its use. Behavioral and physiological responses to fentanyl are found to differ by sex and gender in many cases, including outputs like affective symptoms, analgesia, tolerance, and withdrawal emphasizing the need for further research about the role of biological sex on fentanyl use.
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Overdose de Drogas , Transtornos Relacionados ao Uso de Opioides , Animais , Feminino , Humanos , Masculino , Fentanila/farmacologia , Analgésicos Opioides/farmacologia , Fatores Sexuais , Overdose de Drogas/epidemiologiaRESUMO
In an animal model of compulsive drug use, a subset of rats continues to self-administer cocaine despite footshock consequences and is considered punishment resistant. We recently found that punishment resistance is associated with habits that persist under conditions that typically encourage a transition to goal-directed control. Given that random ratio (RR) and random interval (RI) schedules of reinforcement influence whether responding is goal-directed or habitual, we investigated the influence of these schedules on punishment resistance for cocaine or food. Male and female Sprague Dawley rats were trained to self-administer either intravenous cocaine or food pellets on a seeking-taking chained schedule of reinforcement, with the seeking lever requiring completion of either an RR20 or RI60 schedule. Rats were then given four days of punishment testing with footshock administered at the completion of seeking on a random one-third of trials. For cocaine-trained rats, the RI60 schedule led to greater punishment resistance (i.e., more trials completed) than the RR20 schedule in males and females. For food-trained rats, the RI60 schedule led to greater punishment resistance (i.e., higher reward rates) than the RR20 schedule in female rats, although male rats showed punishment resistance on both RR20 and RI60 schedules. For both cocaine and food, we found that seeking responses were suppressed to a greater degree than reward rate with the RI60 schedule, whereas response rate and reward rate were equally suppressed with the RR20 schedule. This dissociation between punishment effects on reward rate and response rate with the RI60 schedule can be explained by the nonlinear relation between these variables on RI schedules, but it does not account for the enhanced resistance to punishment. Overall, the results show greater punishment resistance with the RI60 schedule as compared to the RR20 schedule, indicating that schedules of reinforcement are an influencing factor on resistance to negative consequences.
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Cocaína , Punição , Ratos Sprague-Dawley , Esquema de Reforço , Autoadministração , Animais , Masculino , Feminino , Cocaína/administração & dosagem , Cocaína/farmacologia , Ratos , Condicionamento Operante/efeitos dos fármacos , Reforço Psicológico , Comportamento de Procura de Droga/efeitos dos fármacos , Comportamento de Procura de Droga/fisiologiaRESUMO
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.
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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
INTRODUCTION: Cigarette smoking remains the leading preventable cause of disease and death. Nicotine is the primary reinforcing ingredient in cigarettes sustaining addiction. Cotinine is the major metabolite of nicotine that produces a myriad of neurobehavioral effects. Previous studies showed that cotinine supported self-administration in rats and rats with a history of cotinine self-administration exhibited relapse-like drug-seeking behavior, suggesting that cotinine may also be reinforcing. To date, whether cotinine may contribute to nicotine reinforcement remains unknown. Nicotine metabolism is mainly catalyzed by hepatic CYP2B1/2 enzymes in rats and methoxsalen is a potent CYP2B1/2 inhibitor. METHODS: The study examined nicotine metabolism, self-administration, and locomotor activity. The hypothesis is that methoxsalen inhibits nicotine self-administration and cotinine replacement attenuates the inhibitory effects of methoxsalen in male rats. RESULTS: Methoxsalen decreased plasma cotinine levels following a subcutaneous nicotine injection. Repeated daily methoxsalen treatments reduced the acquisition of nicotine self-administration, leading to fewer nicotine infusions, lower nicotine intake, and lower plasma cotinine levels. However, methoxsalen did not alter the maintenance of nicotine self-administration despite a significant reduction of plasma cotinine levels. Cotinine replacement by mixing cotinine with nicotine for self-administration dose-dependently increased plasma cotinine levels and enhanced the acquisition of self-administration. Neither basal nor nicotine-induced locomotor activity was altered by methoxsalen. CONCLUSIONS: These results indicate that methoxsalen inhibition of cotinine formation impaired the acquisition of nicotine self-administration, and cotinine replacement attenuated the inhibitory effects of methoxsalen on the acquisition of self-administration, suggesting that cotinine may contribute to the initial development of nicotine reinforcement. IMPLICATIONS: Smoking cessation medications targeting nicotine's effects are only moderately effective, making it imperative to better understand the mechanisms of nicotine misuse. Methoxsalen inhibited nicotine metabolism to cotinine and impaired the acquisition of nicotine self-administration. Cotinine replacement restored plasma cotinine and attenuated the methoxsalen inhibition of nicotine self-administration in rats. These results suggest that (1) the inhibition of nicotine metabolism may be a viable strategy in reducing the development of nicotine reinforcement, (2) methoxsalen may be translationally valuable, and (3) cotinine may be a potential pharmacological target for therapeutic development given its important role in the initial development of nicotine reinforcement.
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INTRODUCTION: The distinctions in the biological impacts of distinct forms of nicotine have become a prominent subject of current research. However, relatively little research has been done on the addictive effects of different forms of nicotine. METHODS: The aerosol self-administration device was briefly characterized by determining aerosol concentration, particle size, and distributional diffusion of the aerosol. And the aerosol self-administration model was constructed at 1, 5, and 10 mg/mL of nicotine to select the appropriate nicotine concentration. Subsequently, the model was used to explore the differences in aerosol self-administration behavior of freebase nicotine and nicotine salts and the behavioral differences after withdrawal. RESULTS: We successfully constructed mouse aerosol self-administration models at 1, 5, and 10 mg/mL nicotine concentrations. In the study of the difference in addictive behaviors between freebase nicotine and nicotine salts, mice with freebase nicotine and different nicotine salts showed varying degrees of drug-seeking behavior, with nicotine benzoate showing the strongest reinforcement. During the withdrawal phase, nicotine salts mice showed more robust anxiety-like behaviors. CONCLUSIONS: These results confirm the successful development and stability of the nicotine aerosol self-administration model. Furthermore, they demonstrated that nicotine salts enhance drug-seeking behavior to a greater extent than freebase nicotine, with nicotine benzoate exhibiting the most significant effects. IMPLICATIONS: In this study, an aerosol self-administered model of mice was constructed, which can be used not only for comparing the effects of freebase nicotine and nicotine salts on the behavior, but also for other addictive drugs, such as fentanyl and cannabis. In addition, this study shows that nicotine salts may be more addictive compared to freebase nicotine, which is a reference for the future use of nicotine salts in tobacco products such as e-cigarettes.
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INTRODUCTION: The prevalence of asthma in adults >65 years old is approximately 12-14%, and 10% have severe asthma. A higher mortality rate is observed in subjects with asthma >65 years old and especially >80 years old. OBJECTIVE: To analyze the effectiveness and safety of at least three doses of benralizumab in a subgroup of elderly subjects (>65 years old) with uncontrolled severe eosinophilic asthma in real-life conditions. METHODS: This was a retrospective multicenter study (AUTOBENRA study) conducted in 9 hospitals that included 72 patients aged >18 years old with uncontrolled severe asthma based on the Spanish Asthma Guidelines who were treated with at least three doses of benralizumab, self-administered at home since before April 30, 2021. The recruitment period ended on October 1, 2021. Written consent was obtained before the study commencement. In this subanalysis, we compared the results between patients >65 years old and patients <65 years old. RESULTS: A total of 72 subjects with severe asthma were screened, and 54 were included (MD: 57.3 ± 10 years old). There were 12 subjects aged >65 years old [MD: 69.8 ± 4.3 years old (minimum: 65 years old; maximum: 83 years old)]. Subjects >65 years old experienced statistically significant improvement in lung function, ACT and mini-AQLQ with benralizumab. Additionally, 9 patients (75%) experienced no asthma exacerbation (p = 0.0047), half (3/6) were able to stop OCS (p = 0.08), and no adverse effects with benralizumab were reported during the 20 months of follow-up. CONCLUSIONS: In patients aged >65 years old, benralizumab was an effective and safe therapy for severe eosinophilic asthma in our study, with no significant differences from the younger subgroup. This is especially important since they are a group with numerous comorbidities, medications and worse quality of life.
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Antiasmáticos , Asma , Eosinofilia Pulmonar , Humanos , Adulto , Idoso , Idoso de 80 Anos ou mais , Adolescente , Pessoa de Meia-Idade , Asma/tratamento farmacológico , Asma/induzido quimicamente , Antiasmáticos/efeitos adversos , Qualidade de Vida , Anticorpos Monoclonais Humanizados/efeitos adversos , Eosinofilia Pulmonar/tratamento farmacológico , Progressão da Doença , EosinófilosRESUMO
Neuronal ensembles in the medial prefrontal cortex mediate cocaine self-administration via projections to the nucleus accumbens. We have recently shown that neuronal ensembles in the prelimbic cortex form rapidly to mediate cocaine self-administration. However, the role of neuronal ensembles within the nucleus accumbens in initial cocaine-seeking behaviour remains unknown. Here, we sought to expand the current literature by testing the necessity of the cocaine self-administration ensemble in the nucleus accumbens core (NAcCore) 1 day after male and female rats acquire cocaine self-administration by using the Daun02 inactivation procedure. We found that disrupting the NAcCore ensembles after a no-cocaine reward-seeking test increased subsequent cocaine seeking, while disrupting NAcCore ensembles following a cocaine self-administration session decreased subsequent cocaine seeking. We then characterized neuronal cell type in the NAcCore using RNAscope in situ hybridization. In the no-cocaine session, we saw reduced dopamine D1 type neuronal activation, while in the cocaine self-administration session, we found preferential dopamine D1 type neuronal activity in the NAcCore.
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Cocaína , Comportamento de Procura de Droga , Neurônios , Núcleo Accumbens , Autoadministração , Animais , Núcleo Accumbens/efeitos dos fármacos , Cocaína/farmacologia , Masculino , Feminino , Ratos , Comportamento de Procura de Droga/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Recompensa , Inibidores da Captação de Dopamina/farmacologia , Reforço Psicológico , Receptores de Dopamina D1 , Transtornos Relacionados ao Uso de Cocaína/fisiopatologia , Ratos Sprague-Dawley , Córtex Pré-Frontal/efeitos dos fármacosRESUMO
Synthetic opioids such as fentanyl contribute to the vast majority of opioid-related overdose deaths, but fentanyl use remains broadly understudied. Like other substances with misuse potential, opioids cause lasting molecular adaptations to brain reward circuits, including neurons in the ventral tegmental area (VTA). The VTA contains numerous cell types that play diverse roles in opioid use and relapse; however, it is unknown how fentanyl experience alters the transcriptional landscape in specific subtypes. Here, we performed single nuclei RNA sequencing to study transcriptional programs in fentanyl-experienced mice. Male and female C57/BL6 mice self-administered intravenous fentanyl (1.5 µg/kg/infusion) or saline for 10 days. After 24 h abstinence, VTA nuclei were isolated and prepared for sequencing on the 10× platform. We identified different patterns of gene expression across cell types. In dopamine neurons, we found enrichment of genes involved in growth hormone signalling. In dopamine-glutamate-GABA combinatorial neurons, and some GABA neurons, we found enrichment of genes involved in Pi3k-Akt signalling. In glutamate neurons, we found enrichment of genes involved in cholinergic signalling. We identified transcriptional regulators for the differentially expressed genes in each neuron cluster, including downregulated transcriptional repressor Bcl6, and upregulated transcription factor Tcf4. We also compared the fentanyl-induced gene expression changes identified in mouse VTA with a published rat dataset in bulk VTA, and found overlap in genes related to GABAergic signalling and extracellular matrix interaction. Together, we provide a comprehensive picture of how fentanyl self-administration alters the transcriptional landscape of the mouse VTA that serves as the foundation for future mechanistic studies.
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Analgésicos Opioides , Fentanila , Camundongos Endogâmicos C57BL , Área Tegmentar Ventral , Animais , Área Tegmentar Ventral/efeitos dos fármacos , Área Tegmentar Ventral/metabolismo , Camundongos , Fentanila/farmacologia , Masculino , Feminino , Analgésicos Opioides/farmacologia , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Autoadministração , Neurônios GABAérgicos/efeitos dos fármacos , Neurônios GABAérgicos/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Transtornos Relacionados ao Uso de Opioides/genéticaRESUMO
The increasing rates of drug misuse highlight the urgency of identifying improved therapeutics for treatment. Most drug-seeking behaviours that can be modelled in rodents utilize the repeated intravenous self-administration (SA) of drugs. Recent studies examining the mesolimbic pathway suggest that Kv7/KCNQ channels may contribute to the transition from recreational to chronic drug use. However, to date, all such studies used noncontingent, experimenter-delivered drug model systems, and the extent to which this effect generalizes to rats trained to self-administer drugs is not known. Here, we tested the ability of retigabine (ezogabine), a Kv7 channel opener, to regulate instrumental behaviour in male Sprague Dawley rats. We first validated the ability of retigabine to target experimenter-delivered cocaine in a conditioned place preference (CPP) assay and found that retigabine reduced the acquisition of place preference. Next, we trained rats for cocaine-SA under a fixed-ratio or progressive-ratio reinforcement schedule and found that retigabine pretreatment attenuated the SA of low to moderate doses of cocaine. This was not observed in parallel experiments, with rats self-administering sucrose, a natural reward. Compared with sucrose-SA, cocaine-SA was associated with reductions in the expression of the Kv7.5 subunit in the nucleus accumbens, without alterations in Kv7.2 and Kv7.3. Therefore, these studies reveal a reward-specific reduction in SA behaviour and support the notion that Kv7 is a potential therapeutic target for human psychiatric diseases with dysfunctional reward circuitry.
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Carbamatos , Cocaína , Fenilenodiaminas , Ratos Sprague-Dawley , Autoadministração , Sacarose , Animais , Fenilenodiaminas/farmacologia , Fenilenodiaminas/administração & dosagem , Carbamatos/farmacologia , Carbamatos/administração & dosagem , Cocaína/farmacologia , Cocaína/administração & dosagem , Masculino , Ratos , Sacarose/administração & dosagem , Sacarose/farmacologia , Comportamento de Procura de Droga/efeitos dos fármacos , Canais de Potássio KCNQ/efeitos dos fármacos , Condicionamento Operante/efeitos dos fármacos , Inibidores da Captação de Dopamina/farmacologia , Inibidores da Captação de Dopamina/administração & dosagemRESUMO
Approximately 50 million Americans suffer from chronic pain, and nearly a quarter of chronic pain patients have reported misusing opioid prescriptions. Repeated drug seeking is associated with reactivation of an ensemble of neurons sparsely scattered throughout the dorsomedial prefrontal cortex (dmPFC). Prior research has demonstrated that chronic pain increases intrinsic excitability of dmPFC neurons, which may increase the likelihood of reactivation during drug seeking. We tested the hypothesis that chronic pain would increase oxycodone-seeking behaviour and that the pain state would differentially increase intrinsic excitability in dmPFC drug-seeking ensemble neurons. TetTag mice self-administered intravenous oxycodone. After 7 days of forced abstinence, a drug-seeking session was performed, and the ensemble was tagged. Mice received spared nerve injury (SNI) to induce chronic pain during the period between the first and second seeking session. Following the second seeking session, we performed electrophysiology on individual neurons within the dmPFC to assess intrinsic excitability of the drug-seeking ensemble and non-ensemble neurons. SNI had no impact on sucrose seeking or intrinsic excitability of dmPFC neurons from these mice. In females, SNI increased oxycodone seeking and intrinsic excitability of non-ensemble neurons. In males, SNI had no impact on oxycodone seeking or neuron excitability. Data from females are consistent with clinical reports that chronic pain can promote drug craving and relapse and support the hypothesis that chronic pain itself may lead to neuroadaptations which promote opioid seeking.
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Analgésicos Opioides , Comportamento de Procura de Droga , Neuralgia , Neurônios , Oxicodona , Córtex Pré-Frontal , Animais , Oxicodona/farmacologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/fisiopatologia , Comportamento de Procura de Droga/efeitos dos fármacos , Camundongos , Neuralgia/fisiopatologia , Neurônios/efeitos dos fármacos , Masculino , Feminino , Analgésicos Opioides/farmacologia , Autoadministração , Dor Crônica/fisiopatologia , Fatores SexuaisRESUMO
Addictive properties of propofol have been demonstrated in both humans and animals. The nucleus accumbens (NAc) shell (NAsh) in the brain, along with the interactions between N-methyl-D-aspartate receptor (NMDAR) and the dopamine D1 receptor (D1R), as well as their downstream ERK/CREB signalling pathway in the NAc, are integral in regulating reward-seeking behaviour. Nevertheless, it remains unclear whether NMDARs and the NMDAR-D1R/ERK/CREB signalling pathway in the NAsh are involved in mediating propofol addiction. To investigate it, we conducted experiments with adult male Sprague-Dawley rats to establish a model of propofol self-administration behaviour. Subsequently, we microinjected D-AP5 (a competitive antagonist of NMDARs, 1.0-4.0 µg/0.3 µL/site) or vehicle into bilateral NAsh in rats that had previously self-administered propofol to examine the impact of NMDARs within the NAsh on propofol self-administration behaviour. Additionally, we examined the protein expressions of NR2A and NR2B subunits, and the D1R/ERK/CREB signalling pathways within the NAc. The results revealed that propofol administration behaviour was enhanced by D-AP5 pretreatment in NAsh, accompanied by elevated expressions of phosphorylation of NR2A (Tyr1246) and NR2B (Tyr1472) subunits. There were statistically significant increases in the expressions of D1Rs, as well as in the phosphorylated ERK1/2 (p-ERK1/2) and CREB (p-CREB). This evidence substantiates a pivotal role of NMDARs in the NAsh, with a particular emphasis on the NR2A and NR2B subunits, in mediating propofol self-administration behaviour. Furthermore, it suggests that this central reward processing mechanism may operate through the NMDAR-D1R/ERK/CREB signal transduction pathway.
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Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico , Núcleo Accumbens , Propofol , Ratos Sprague-Dawley , Receptores de Dopamina D1 , Receptores de N-Metil-D-Aspartato , Autoadministração , Transdução de Sinais , Animais , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Propofol/farmacologia , Receptores de N-Metil-D-Aspartato/metabolismo , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Masculino , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D1/efeitos dos fármacos , Ratos , Transdução de Sinais/efeitos dos fármacos , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacosRESUMO
The endocannabinoid system interacts with the reward system to modulate responsiveness to natural reinforcers, as well as drugs of abuse. Previous preclinical studies suggested that direct blockade of CB1 cannabinoid receptors (CB1R) could be leveraged as a potential pharmacological approach to treat substance use disorder, but this strategy failed during clinical trials due to severe psychiatric side effects. Alternative strategies have emerged to circumvent the side effects of direct CB1 binding through the development of allosteric modulators. We hypothesized that negative allosteric modulation of CB1R signalling would reduce the reinforcing properties of morphine and decrease behaviours associated with opioid misuse. By employing intravenous self-administration in mice, we studied the effects of GAT358, a functionally-biased CB1R negative allosteric modulator (NAM), on morphine intake, relapse-like behaviour and motivation to work for morphine infusions. GAT358 reduced morphine infusion intake during the maintenance phase of morphine self-administration under a fixed ratio 1 schedule of reinforcement. GAT358 also decreased morphine-seeking behaviour after forced abstinence. Moreover, GAT358 dose dependently decreased the motivation to obtain morphine infusions under a progressive ratio schedule of reinforcement. Strikingly, GAT358 did not affect the motivation to work for food rewards in an identical progressive ratio task, suggesting that the effect of GAT358 in decreasing opioid self-administration was reward specific. Furthermore, GAT58 did not produce motor ataxia in the rotarod test. Our results suggest that CB1R NAMs reduced the reinforcing properties of morphine and could represent a viable therapeutic route to safely decrease misuse of opioids.
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Morfina , Receptor CB1 de Canabinoide , Autoadministração , Animais , Morfina/farmacologia , Morfina/administração & dosagem , Receptor CB1 de Canabinoide/efeitos dos fármacos , Camundongos , Regulação Alostérica/efeitos dos fármacos , Masculino , Comportamento de Procura de Droga/efeitos dos fármacos , Recidiva , Reforço Psicológico , Motivação/efeitos dos fármacos , Analgésicos Opioides/farmacologia , Analgésicos Opioides/administração & dosagem , Administração Intravenosa , Condicionamento Operante/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacosRESUMO
Microglia are widely known for their role in immune surveillance and for their ability to refine neurocircuitry during development, but a growing body of evidence suggests that microglia may also play a complementary role to neurons in regulating the behavioral aspects of substance use disorders. While many of these efforts have focused on changes in microglial gene expression associated with drug-taking, epigenetic regulation of these changes has yet to be fully understood. This review provides recent evidence supporting the role of microglia in various aspects of substance use disorder, with particular focus on changes to the microglial transcriptome and the potential epigenetic mechanisms driving these changes. Further, this review discusses the latest technical advances in low-input chromatin profiling and highlights the current challenges for studying these novel molecular mechanisms in microglia.
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Microglia , Transtornos Relacionados ao Uso de Substâncias , Humanos , Microglia/metabolismo , Epigênese Genética , Cromatina/metabolismo , Transtornos Relacionados ao Uso de Substâncias/genética , Transtornos Relacionados ao Uso de Substâncias/metabolismo , TranscriptomaRESUMO
Enduring patterns of epigenomic and transcriptional plasticity within the mesolimbic dopamine system contribute importantly to persistent behavioral adaptations that characterize substance use disorders (SUD). While drug addiction has long been thought of as a disorder of dopamine (DA) neurotransmission, therapeutic interventions targeting receptor mediated DA-signaling have not yet resulted in efficacious treatments. Our laboratory recently identified a non-canonical, neurotransmission-independent signaling moiety for DA in brain, termed dopaminylation, whereby DA itself acts as a donor source for the establishment of post-translational modifications (PTM) on substrate proteins (e.g., histone H3 at glutamine 5; H3Q5dop). In our previous studies, we demonstrated that H3Q5dop plays a critical role in the regulation of neuronal transcription and, when perturbed within monoaminergic neurons of the ventral tegmental area (VTA), critically contributes to pathological states, including relapse vulnerability to both psychostimulants (e.g., cocaine) and opiates (e.g., heroin). Importantly, H3Q5dop is also observed throughout the mesolimbic DA reward pathway (e.g., in nucleus accumbens/NAc and medial prefrontal cortex/mPFC, which receive DA input from VTA). As such, we investigated whether H3Q5dop may similarly be altered in its expression in response to drugs of abuse in these non-dopamine-producing regions. In rats undergoing extended abstinence from cocaine self-administration (SA), we observed both acute and prolonged accumulation of H3Q5dop in NAc, but not mPFC. Attenuation of H3Q5dop in NAc during drug abstinence reduced cocaine-seeking and affected cocaine-induced gene expression programs associated with altered dopamine signaling and neuronal function. These findings thus establish H3Q5dop in NAc, but not mPFC, as an important mediator of cocaine-induced behavioral and transcriptional plasticity during extended cocaine abstinence.
Assuntos
Cocaína , Ratos , Animais , Cocaína/farmacologia , Núcleo Accumbens/metabolismo , Histonas/metabolismo , Ratos Sprague-Dawley , Área Tegmentar Ventral/metabolismo , Dopamina/metabolismo , Córtex Pré-Frontal/metabolismoRESUMO
OBJECTIVES: In response to the Omicron surge in early 2022, the HTA Philippines evaluated the acceptability of Filipinos in using self-administered antigen tests (SAAgTs) as part of COVID-19 HTAs in the Philippines. METHODS: Scoping review from literature databases was initially conducted to identify preset codes in the use of SAAgT. Preset codes were used to establish the questions for focus group discussions (FGDs). Semi-structured questionnaires were created through Delphi technique. FGDs with four stakeholder groups (i.e., nine healthcare workers [HCWs], seven representatives of at-risk groups, six economic frontliners, and seven representatives of micro-small-medium-sized enterprises) were conducted. RESULTS: Discomfort in being a target of stigma and being prescribed an "illness identity" when suspected or confirmed COVID-19-positive, along with lack of confidence to perform self-test, caused hesitancy in self-testing among participants. The need for subsidies for test kits from the government or employers was emphasized to increase its accessibility. Having a designated access point and reporting system for SAAgT was highlighted to avoid nepotism (padrino system attributed to debt of gratitude), inequitable distribution, and lapses in reporting. A participatory approach to education was perceived as crucial to reduce any misconceptions associated with the use of SAAgT. CONCLUSIONS: All FGD groups expressed favorable reviews on the implementation of SAAgT because it can potentially reduce the burden of health facility-administered tests. These findings were considered by the HTA Council in the recommendation of SAAgT as part of the overarching national strategies for the diagnosis and screening of COVID-19.
Assuntos
COVID-19 , Humanos , COVID-19/diagnóstico , COVID-19/epidemiologia , Filipinas , Grupos Focais , Teste para COVID-19RESUMO
BACKGROUND: Medication self-management (MSM) is defined as a person's ability to cope with medication treatment for a chronic condition, along with the associated physical and psychosocial effects that the medication causes in their daily lives. For many patients, it is important to be able to self-manage their medication successfully, as they will often be expected to do after discharge. AIM: The aim of this study was to describe the willingness and attitudes of patients with schizophrenia spectrum or bipolar disorders regarding MSM during hospital admission. A secondary aim was to identify various factors associated with patient willingness to participate in MSM and to describe their assumptions concerning needs and necessary conditions, as well as their attitudes towards their medication. METHODS: A multicentre, quantitative cross-sectional observational design was used to study the willingness and attitudes of psychiatric patients regarding MSM during hospitalisation. The study adhered to guidelines for Strengthening the Reporting of Observational Studies in Epidemiology (STROBE). RESULTS: In this study, 84 patients, of which 43 were patients with schizophrenia spectrum disorders and 41 were patients with bipolar disorders, participated. A majority of the patients (81%) were willing to participate in MSM during their hospitalisation. Analysis revealed patients are more willing to MSM if they are younger (r = -.417, p < .001) and a decreasing number of medicines (r = -.373, p = .003). Patients' willingness was positively associated with the extent of support by significant others during and after hospitalisation (Pearson's r = .298, p = .011). Patients were convinced that they would take their medication more correctly if MSM were to be allowed during hospitalisation (65%). CONCLUSION: Most of the patients were willing to self-manage their medication during hospitalisation, however, under specific conditions such as being motivated to take their medication correctly and to understand the benefits of their medication. RELEVANCE TO CLINICAL PRACTICE: From a policy point of view, our study provided useful insights into how patients look at MSM to enable the development of future strategies. Since patients are willing to self-manage their medication during hospitalisation, this may facilitate its implementation. PATIENT CONTRIBUTION: Patients were recruited for this study. Participation was voluntary, and signed informed consent was obtained from all participants prior to the questionnaire.
Assuntos
Transtorno Bipolar , Esquizofrenia , Autogestão , Humanos , Transtorno Bipolar/tratamento farmacológico , Esquizofrenia/tratamento farmacológico , Estudos Transversais , HospitalizaçãoRESUMO
OBJECTIVES: Self-administration consists in the administration of medications by the patient himself during his hospitalization. The order of October 10, 2022 (Arrêté du 10 octobre 2022 modifiant l'arrêté du 6 avril 2011) modified the April 6, 2011 regulation to allow and regulate self-administration practices in hospital units. This evolution opens new perspectives for patient autonomy. The objective of this study is, firstly, to evaluate the rate of medication errors from patients under self-administration and secondly, to evaluate the satisfaction of patients and caregivers. MATERIAL AND METHODS: Eligible patients were recruited from a locomotor and polyvalent rehabilitation unit. After verification of eligibility, explanation given to the patient about the hospital self-administration of medication procedure and signature of the compliance agreement, patients started self-administration. Medication errors were reported during seven days. Evaluations of patient and staff satisfaction were also carried out. RESULTS: Of the 83 patients admitted to the care service, 32 were able to experiment self-administered medication procedure during their hospitalization. To assess the safety of this practice, 1235 drug intakes were analyzed. Ninety-four administration errors were noted: 98% of them concerned analgesic drugs. All of these errors were omissions and none of them were rated as serious. The 20 patients questioned were all satisfied with self-administration. The 14 carers interviewed were satisfied with this change in practice. CONCLUSION: The medication self-administration process set up in the rehabilitation unit did not lead to serious medication errors. Patients and caregivers reported being satisfied with this new hospital practice.