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BACKGROUND: Social status in humans, generally reflected by socioeconomic status, has been associated, when constrained, with heightened vulnerability to pathologies including psychiatric diseases. Social hierarchy in mice translates into individual and interdependent behavioral strategies of animals within a group. The rules leading to the emergence of a social organization are elusive, and detangling the contribution of social status from other factors, whether environmental or genetic, to normal and pathological behaviors remains challenging. METHODS: We investigated the mechanisms shaping the emergence of a social hierarchy in isogenic C57BL/6 mice raised in groups of 4 using conditional mutant mouse models and chemogenetic manipulation of dopamine midbrain neuronal activity. We further studied the evolution of behavioral traits and the vulnerability to psychopathological-like phenotypes according to the social status of the animals. RESULTS: Higher sociability predetermined higher social hierarchy in the colony. Upon hierarchy establishment, higher-ranked mice showed increased anxiety and better cognitive abilities in a working memory task. Strikingly, the higher-ranked mice displayed a reduced activity of dopaminergic neurons within the ventral tegmental area, paired with a decreased behavioral response to cocaine and a decreased vulnerability to depressive-like behaviors following repeated social defeats. The pharmacogenetic inhibition of this neuronal population and the genetic inactivation of glucocorticoid receptor signaling in dopamine-sensing brain areas that resulted in decreased dopaminergic activity promoted accession to higher social ranks. CONCLUSIONS: Dopamine activity and its modulation by the stress response shapes social organization in mice, potentially linking interindividual and social status differences in vulnerability to psychopathologies.
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Neurônios Dopaminérgicos , Transtornos Mentais , Humanos , Camundongos , Animais , Dopamina , Hierarquia Social , Camundongos Endogâmicos C57BL , Área Tegmentar VentralRESUMO
BACKGROUND AND AIMS: Pre-clinical studies suggest that the simultaneous blockade of the α1b and 5HT2A receptors may be effective in reducing alcohol consumption. This study aimed to assess the efficacy and safety of prazosin (α1b blocker) and cyproheptadine (5HT2A blocker) combination in decreasing total alcohol consumption (TAC) in alcohol use disorder (AUD). DESIGN, SETTING AND PARTICIPANTS: This was a double-blind, parallel group, placebo-controlled, Phase 2, randomized clinical trial conducted in 32 addiction treatment centres in France. A total of 108 men and 46 women with severe AUD took part. INTERVENTION: Participants were randomly assigned to one of the following 3-month treatments: (1) low-dose group (LDG) receiving 8 mg cyproheptadine and 5 mg prazosin extended-release (ER) formulation daily; (2) high-dose group (HDG) receiving 12 mg cyproheptadine and 10 mg prazosin ER daily; and (3) placebo group (PG) receiving placebo of cyproheptadine and prazosin ER. A total of 154 patients were randomized: 54 in the PG, 54 in the LDG and 46 in the HDG. MEASUREMENTS: The primary outcome was TAC change from baseline to month 3. FINDINGS: A significant main treatment effect in the change in TAC was found in the intent-to-treat population (P = 0.039). The HDG and LDG showed a benefit in the change in TAC from baseline to month 3 compared with PG: -23.6 g/day, P = 0.016, Cohen's d = -0.44; -18.4 g/day, P = 0.048 (Bonferroni correction P < 0.025), Cohen's d = -0.36. In a subgroup of very high-risk drinking-level participants (> 100 g/day of pure alcohol for men and > 60 g/day for women), the difference between the HDG and the PG in the primary outcome was -29.8 g/day (P = 0.031, Cohen's d = -0.51). The high and low doses were well-tolerated with a similar safety profile. CONCLUSIONS: A randomized controlled trial of treatment of severe alcohol use disorder with a cyproheptadine-prazosin combination for 3 months reduced drinking by more than 23 g per day compared with placebo. A higher dose combination was associated with a larger magnitude of drinking reduction than a lower dose combination while showing similar safety profile.
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Ciproeptadina , Quimioterapia Combinada , Prazosina , Humanos , Masculino , Método Duplo-Cego , Feminino , Ciproeptadina/uso terapêutico , Prazosina/uso terapêutico , Adulto , Pessoa de Meia-Idade , Resultado do Tratamento , Alcoolismo/tratamento farmacológico , Antagonistas de Receptores Adrenérgicos alfa 1/uso terapêutico , Antagonistas da Serotonina/uso terapêutico , França , Consumo de Bebidas Alcoólicas , Preparações de Ação Retardada , Relação Dose-Resposta a DrogaRESUMO
The European Union Tobacco Products Directive (EU TPD) mandates enhanced reporting obligations for tobacco manufacturers regarding 15 priority additives. Within the Joint Action on Tobacco Control (JATC), a review panel of independent experts was appointed for the scientific evaluation of the additive reports submitted by a consortium of 12 tobacco manufacturers. As required by the TPD, the reports were evaluated based on their comprehensiveness, methodology and conclusions. In addition, we evaluated the chemical, toxicological, addictive, inhalation facilitating and flavoring properties of the priority additives based on the submitted reports, supplemented by the panel's expert knowledge and some independent literature. The industry concluded that none of the additives is associated with concern. Due to significant methodological limitations, we question the scientific validity of these conclusions and conclude that they are not warranted. Our review demonstrates that many issues regarding toxicity, addictiveness and attractiveness of the additives have not been sufficiently addressed, and therefore concerns remain. For example, menthol facilitates inhalation by activation of the cooling receptor TRPM8. The addition of sorbitol and guar gum leads to a significant increase of aldehydes that may contribute to toxicity and addictiveness. Titanium dioxide particles (aerodynamic diameter <10 µm) are legally classified as carcinogenic when inhaled. For diacetyl no report was provided. Overall, the industry reports were not comprehensive, and the information presented provides an insufficient basis for the regulation of most additives. We, therefore, advise MS to consider alternative approaches such as the precautionary principle.
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The Tobacco Products Directive (TPD) defines enhanced reporting obligations applying to 15 priority additives added to cigarettes and roll-your-own tobacco. A consortium of 12 international tobacco companies submitted 14 reports that were reviewed by an independent scientific body within the Joint Action on Tobacco Control (JATC). The reports were evaluated in accordance with the TPD with regard to their comprehensiveness, methodology and conclusions. Here we present their significant identified methodological limitations. The toxicological and chemical evaluation in the industry reports was mainly based on comparative testing, which lacks discriminative power for products with high toxicity and variability, like cigarettes. The literature reviews were biased, the comparative chemical studies did not assess previously identified pyrolysis products, the toxicological evaluation did not include the assessment of inhalation toxicity, and pyrolysis products were not assessed in terms of toxicity, including their genotoxic and carcinogenic potential. For both chemistry and toxicity testing, the statistical approach applied to test the difference between test and additive-free control cigarettes resulted in a high chance of false negatives. The clinical study for inhalation facilitation and nicotine uptake had limitations concerning study design and statistical analysis, while addictiveness was not assessed. Finally, the methodology used to assess characterizing flavors was flawed. In conclusion, there are significant limitations in the methodology applied by the industry. Therefore, the provided reports are of insufficient quality and are clearly not suitable to decide whether a priority additive should be banned in tobacco products according to the TPD.
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Although nicotine is generally considered to be the main compound responsible for addictive properties of tobacco, experimental data indicate that nicotine does not exhibit all the characteristics of other substances of abuse. We recently showed that a pretreatment with mixed irreversible monoamine oxidases inhibitors (MAOIs), such as tranylcypromine, triggers a locomotor response to nicotine in mice and allows maintenance of behavioral sensitization to nicotine in rats. Moreover, we showed by microdialysis in mice that behavioral sensitization induced by compounds belonging to main groups of drugs of abuse, such as amphetamine, cocaine, morphine, or alcohol, was underlain by sensitization of noradrenergic and serotonergic neurons. Here, this neurochemical sensitization was tested after nicotine, tranylcypromine, or a mixture of both compounds. Data indicate that, whereas neither repeated nicotine nor repeated tranylcypromine alone has any effect by itself, a repeated treatment with a mixture of nicotine and tranylcypromine induces both behavioral sensitization and sensitization of noradrenergic and serotonergic neurons. The development of neurochemical and behavioral sensitizations is blocked by prazosin and SR46349B [(1Z,2E)-1-(2-fluoro-phenyl)-3-(4-hydroxyphenyl)-prop-2-en-one-O-(2-dimethylamino-ethyl)-oxime hemifumarate], two antagonists of alpha1b-adrenergic and 5-HT(2A) receptors, respectively, but not by SCH23390 [R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride], a D(1) receptor antagonist. Finally, we found that pretreatments with WAY 100635 [N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclo-hexane carboxamide trihydrochloride], a 5-HT(1A) receptor antagonist, can also induce a behavioral and neurochemical sensitization to repeated nicotine. Complementary experiments with 8-OHDPAT (8-hydroxy-dipropylamino-tetralin), a 5-HT(1A) receptor agonist, and analysis of 5-HT(1A) receptors expression in the dorsal raphe nucleus after a tranylcypromine injection indicate that MAOIs contained in tobacco desensitize 5-HT(1A) autoreceptors to trigger the strong addictive properties of tobacco.
Assuntos
Comportamento Animal/efeitos dos fármacos , Química Encefálica/efeitos dos fármacos , Monoaminoxidase/metabolismo , Nicotina/farmacologia , Agonistas Nicotínicos/farmacologia , Receptor 5-HT1A de Serotonina/metabolismo , 8-Hidroxi-2-(di-n-propilamino)tetralina/farmacologia , Animais , Autorreceptores/metabolismo , Combinação de Medicamentos , Fluorbenzenos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Inibidores da Monoaminoxidase/farmacologia , Fenóis/farmacologia , Piperazinas/farmacologia , Prazosina/farmacologia , Piridinas/farmacologia , Núcleos da Rafe/efeitos dos fármacos , Antagonistas da Serotonina/farmacologia , Agonistas do Receptor de Serotonina/farmacologia , Tranilcipromina/farmacologiaRESUMO
This article, corresponding to a part of the restitution of a financed international research project between France, Brazil, Canada, Italy and Belgium, aims to offer a modelisation and qualitative evaluation of mediation care settings based on an original methodological tool that involves identifying the typical games at the foundations of creativity, following a multidisciplinary perspective. Therapeutic mediations are settings or devices organized around a "pliable medium," often artistic, like painting, modeling, writing and theater, which are very widespread in institutional practices, both in France and abroad. The scientific objectives of this research consist in a multi-disciplinary exploration (anthropology, criminology, neuroscience, clinical psychology) of the process of creative symbolization understood as a process of transformation involving play. According to this orientation, play can be defined as a psychic process whereby a subjective experience can be explored with pleasure, and consequently symbolized and appropriated. Our fundamental and original hypothesis is that play is at the source of the creative process, conceived as a work of metabolization by the psyche of playful experiences during the different stages of life. The review of the understanding of play in psychoanalysis, anthropology, criminology and neuroscience emphasizes the richness of this model and the importance of reflecting on the typical games in the field of psychic care. A clinical example of treatment in a pictorial therapeutic mediation setting of a child with psychotic disorders makes it possible to identify a number of typical games as well as the modalities of interpretation of the therapists through play. These multidisciplinary studies lead to the presentation of a general table of typical games, and these first results highlight the richness of identifying typical games in clinical settings. Ultimately, the multidisciplinary approach shows the interest of the model of play in the evaluation of therapeutic mediation settings, with a convergence of the different disciplines emphasizing the pertinence of this model. The scientific impact of this research overlaps with its societal impact, through the development of innovative tools for evaluating therapeutic mediations, in order to take account of the evolution of the different forms of social expression of psychic suffering.
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The aim of the present study was to strengthen our hypothesis of a common physiological basis for post-traumatic stress disorder (PTSD) and substance use disorders. This paper investigates the possibility that rats exposed to a PTSD model exhibit noradrenergic and behavioral sensitization, as observed following repeated drugs of abuse injections. First, rats received a single prolonged stress (SPS), combining three consecutive stressors. They were then tested, 2 weeks after the trauma for PTSD-like symptoms to discriminate between vulnerable and resilient rats. When microdialysis was performed in the prelimbic cortex (Experiment 1), larger increases of noradrenaline (NA) release in response to amphetamine were observed in vulnerable rats when compared to control and resilient animals. Experiment 2 showed that trauma-vulnerable rats exhibited increases in locomotor activity relative to controls, in response to an exposure to trauma-associated cues. These data demonstrate that a single trauma exposure induces in vulnerable animals both, a noradrenergic sensitization evidenced within the prelimbic cortex and behavioral sensitization obtained after a physiologic activation of the noradrenergic system. However, Experiment 3 showed that when NA system was activated by amphetamine (1 mg/kg), a decrease in behavioral sensitization was obtained in vulnerable rats. We proposed that this decreased locomotor activity results from an additional stress-induced increased reactivity of mesocortical dopaminergic neurons, known to counteract the consequences of cortical noradrenergic release in rats. These results support our hypothesis that noradrenergic sensitization represents a common physiological basis, involved both in PTSD and drug addiction and suggest new common therapeutic approaches for these pathologies.
Assuntos
Sistema Límbico/metabolismo , Norepinefrina/metabolismo , Transtornos de Estresse Pós-Traumáticos/metabolismo , Transtornos Relacionados ao Uso de Substâncias/metabolismo , Anfetamina/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Modelos Animais de Doenças , Sistema Límbico/efeitos dos fármacos , Atividade Motora/efeitos dos fármacos , Ratos , Ratos Sprague-DawleyRESUMO
A challenge in drug dependence is to delineate long-term neurochemical modifications induced by drugs of abuse. Repeated d-amphetamine was recently shown to disrupt a mutual regulatory link between noradrenergic and serotonergic neurons, thus inducing long-term increased responses to d-amphetamine and para-chloroamphetamine, respectively. We show here that such a sensitization of noradrenergic and serotonergic neurons also occurs following repeated treatment with cocaine, morphine, or alcohol, three compounds belonging to main groups of addictive substances. In all cases, this sensitization is prevented by alpha 1b-adrenergic and 5-HT2A receptors blockade, indicating the critical role of these receptors on long-term effects of drugs of abuse. However, repeated treatments with two non-addictive antidepressants, venlafaxine, and clorimipramine, which nevertheless inhibit noradrenergic and serotonergic reuptake, do not induce noradrenergic and serotonergic neurons sensitization. Similarly, this sensitization does not occur following repeated treatments with a specific inhibitor of dopamine (DA) reuptake, GBR12783. Moreover, we show that the effects of SCH23390, a D1 receptor antagonist known to inhibit development of d-amphetamine behavioral sensitization, are due to its 5-HT2C receptor agonist property. SCH23390 blocks amphetamine-induced release of norepinephrine and RS102221, a 5-HT2C antagonist, can reverse this inhibition as well as inhibition of noradrenergic sensitization and development of behavioral sensitization induced by repeated d-amphetamine. We propose that noradrenergic/serotonergic uncoupling is a common neurochemical consequence of repeated consumption of drugs of abuse, unrelated with DA release. Our data also suggest that compounds able to restore the link between noradrenergic and serotonergic modulatory systems could represent important therapeutic targets for investigation.
Assuntos
Atividade Motora/fisiologia , Neurônios/fisiologia , Serotonina/metabolismo , Transtornos Relacionados ao Uso de Substâncias/patologia , Transtornos Relacionados ao Uso de Substâncias/fisiopatologia , Animais , Comportamento Animal/efeitos dos fármacos , Química Encefálica/efeitos dos fármacos , Cocaína/efeitos adversos , Modelos Animais de Doenças , Dopamina/metabolismo , Dopaminérgicos/administração & dosagem , Esquema de Medicação , Interações Medicamentosas , Etanol/efeitos adversos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Morfina/efeitos adversos , Atividade Motora/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Norepinefrina/metabolismo , Serotoninérgicos/farmacologia , Transtornos Relacionados ao Uso de Substâncias/etiologia , Transtornos Relacionados ao Uso de Substâncias/metabolismo , p-Cloroanfetamina/efeitos adversosRESUMO
A challenge in drug dependence is to delineate long-term behavioral and neurochemical modifications induced by drugs of abuse. In rodents, drugs of abuse induce locomotor hyperactivity, and repeating injections enhance this response. This effect, called behavioral sensitization, persists many months after the last administration, thus mimicking long-term sensitivity to drugs observed in human addicts. Although addictive properties of drugs of abuse are generally considered to be mediated by an increased release of dopamine in the ventral striatum, recent pharmacological and genetic experiments indicate an implication of alpha1b-adrenergic receptors in behavioral and rewarding responses to psychostimulants and opiates. Later on, it was shown that not only noradrenergic but also serotonergic systems, through 5-HT(2A) receptors, were controlling behavioral effects of drugs of abuse. More recently, experiments performed in animals knockout for alpha1b-adrenergic or 5-HT(2A) receptors indicated that noradrenergic and serotonergic neurons, besides their activating effects, inhibit each other by means of the stimulation of alpha1b-adrenergic and 5-HT(2A) receptors and that this mutual inhibition vanishes in wild type mice with repeated injections of psychostimulants, opiates or alcohol. Uncoupling induced by repeated treatments with drugs of abuse installs a stable sensitization of noradrenergic and serotonergic neurons, thus explaining an increased reactivity of dopaminergic neurons and behavioral sensitization. We propose that noradrenergic/serotonergic uncoupling is a common stable neurochemical consequence of repeated drugs of abuse which may also occur during chronic stressful situations and facilitate the onset of mental illness. Drug consumption would facilitate an artificial re-coupling of these neurons, thus bringing a temporary relief.
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Comportamento/efeitos dos fármacos , Drogas Ilícitas/farmacologia , Receptor 5-HT2A de Serotonina/fisiologia , Receptores Adrenérgicos alfa 1/fisiologia , Transtornos Relacionados ao Uso de Substâncias/etiologia , Animais , Estimulantes do Sistema Nervoso Central/farmacologia , Cicloexanóis/farmacologia , Dextroanfetamina/farmacologia , Dopamina/fisiologia , Humanos , Morfina/farmacologia , Atividade Motora/efeitos dos fármacos , Entorpecentes/farmacologia , Nicotiana , Cloridrato de Venlafaxina , p-Cloroanfetamina/farmacologiaRESUMO
Central serotonin systems have long been associated with the control of feeding behavior and the modulation of behavioral effects of psychostimulants. 5-HT2C receptors are present in hypothalamic centers such as the arcuate nucleus (ARC), controlling homeostatic regulation of food intake, as well as in the ventral tegmental area (VTA), a region involved in motivation aspects in multiple behaviors, including feeding. In the present study, we investigated whether the 5-HT2C receptors control amphetamine-evoked locomotor activity and regulate food consumption. Localized microinjections into the VTA or the ARC were used to assess the effects of a highly selective 5-HT2C receptor agonist, AR231630, on the locomotor stimulant effect of amphetamine as well as on food intake. AR231630 injected into the VTA, but not into the ARC, dose-dependently reduced locomotor activity elicited by amphetamine. Unexpectedly, intra-ARC injection of AR231630 did not reduce food intake even at the dose of 10⯵g, whereas intra-VTA injection of the same dose of AR231630 did. In addition, we showed that pretreatment with the selective 5-HT2C receptor antagonist SB242084 infused into the VTA partially prevented hypophagia induced by peripheral administration of AR231630. We can conclude that 5-HT2C receptor in the VTA, but not in the ARC, participates in both homeostatic and hedonic food intake and brain reward function.
Assuntos
Núcleo Arqueado do Hipotálamo/metabolismo , Comportamento Alimentar/fisiologia , Atividade Motora/fisiologia , Piperazinas/farmacologia , Receptor 5-HT2C de Serotonina/metabolismo , Recompensa , Área Tegmentar Ventral/metabolismo , Aminopiridinas/farmacologia , Anfetamina/farmacologia , Animais , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Estimulantes do Sistema Nervoso Central/farmacologia , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Privação de Alimentos , Indóis/farmacologia , Masculino , Motivação/efeitos dos fármacos , Motivação/fisiologia , Atividade Motora/efeitos dos fármacos , Ratos Sprague-Dawley , Agonistas do Receptor 5-HT2 de Serotonina/farmacologia , Antagonistas do Receptor 5-HT2 de Serotonina/farmacologia , Área Tegmentar Ventral/efeitos dos fármacosRESUMO
RATIONALE: Although locomotor response to d-amphetamine is considered as mediated by an increased release of dopamine in the ventral striatum, blockade of either alpha1b-adrenergic or 5-HT2A receptors almost completely inhibits d-amphetamine-induced locomotor response in mice. In agreement with this finding, mice lacking alpha1b-adrenergic receptors hardly respond to d-amphetamine. However, we show here that, paradoxically, mice lacking 5-HT2A receptors (5-HT2A-R KO) exhibit a twofold higher locomotor response to d-amphetamine than wild-type (WT) littermates. OBJECTIVES: To explore why there is a discrepancy between pharmacological and genetic 5-HT2A receptor blockade. MATERIALS AND METHODS: Locomotor response and behavioral sensitization to d-amphetamine were measured in presence of prazosin and/or SR46349B, alpha1b-adrenergic, and 5-HT2A receptor antagonists, respectively. RESULTS: Repeating amphetamine injections still increases 5-HT2A-R KO mice locomotor response to d-amphetamine at a level similar to that of sensitized WT mice. SR46349B (1 mg/kg) has, as expected, no effect in 5-HT2A-R KO mice. One milligrams per kilogram of prazosin completely blocks d-amphetamine-induced locomotor response in 5-HT2A-R KO naïve animals but 3 mg/kg is necessary in sensitized 5-HT2A-R KO mice. CONCLUSIONS: Because naïve 5-HT2A-R KO mice exhibit an increased cortical noradrenergic response to d-amphetamine, our data suggest that repeated d-amphetamine modifies noradrenergic transmission in 5-HT2A-R KO mice. Stimulation of specific 5-HT2A receptors would inhibit noradrenergic neurons. Dramatic decrease in SR46349B efficiency in sensitized WT mice indicates that a disruption of the regulating role of 5-HT2A receptors on noradrenergic transmission occurs during sensitization and thus represents the physiological basis of behavioral sensitization to d-amphetamine.
Assuntos
Comportamento Animal/efeitos dos fármacos , Dextroanfetamina/farmacologia , Receptor 5-HT2A de Serotonina/fisiologia , Antagonistas de Receptores Adrenérgicos alfa 1 , Animais , Comportamento Animal/fisiologia , Estimulantes do Sistema Nervoso Central/farmacologia , Relação Dose-Resposta a Droga , Fluorbenzenos/farmacologia , Antagonistas dos Receptores H2 da Histamina/farmacologia , Camundongos , Camundongos Knockout , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Fenóis/farmacologia , Prazosina/farmacologia , Receptor 5-HT2A de Serotonina/deficiência , Receptor 5-HT2A de Serotonina/genéticaRESUMO
BACKGROUND AND PURPOSE: It has recently been suggested that 5-HT3 receptor blockade enhances the efficacy of selective 5-HT (serotonin) reuptake inhibitor (SSRI) antidepressants and may reverse stress-induced deficits in rodents. EXPERIMENTAL APPROACH: To further explore this hypothesis, we used mice lacking the 5-HT3 receptor (Htr3a KO) and their wild-type (WT) controls to assess their response in behavioural paradigms relevant to anxiety and depression. Mice were studied under basal, antidepressant treatments and chronic social defeat stress (CSDS) conditions. KEY RESULTS: In basal conditions, Htr3a KO mice displayed anxiolytic- and antidepressant-like behaviours in the elevated plus maze, the social interaction and the forced swim tests (FST), but behaved as WT mice in response to acute citalopram in the FST. However, the effects of fluoxetine were blunted in Htr3a KO mice in these same tests. In an in vitro electrophysiological paradigm, a low-dose citalopram treatment triggered 5-HT1A receptor desensitization only in the dorsal raphe nucleus of Htr3a KO, although a high dose desensitized 5-HT1A autoreceptor function equally in Htr3a KO and WT mice, suggesting that citalopram may become effective at lower doses when 5-HT3 receptors are inactivated. In addition, Htr3a deletion blocked CSDS-induced modification in the cortical expression of two genes involved in oxidative stress, CaMKIIa and SOD1. CONCLUSIONS AND IMPLICATIONS: Taken together, these data show that Htr3a deletion promotes SSRI efficacy and prevents the occurrence of stress-induced deleterious effects, suggesting that the 5-HT3 receptor may represent an interesting target for the treatment of stress-related disorders.
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Antidepressivos/farmacologia , Citalopram/farmacologia , Receptores 5-HT3 de Serotonina/metabolismo , Comportamento Social , Estresse Psicológico/tratamento farmacológico , Animais , Antidepressivos/administração & dosagem , Citalopram/administração & dosagem , Relação Dose-Resposta a Droga , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estresse Oxidativo/efeitos dos fármacos , Receptores 5-HT3 de Serotonina/deficiênciaRESUMO
Although nicotine is generally considered to be the main compound responsible for the addictive properties of tobacco, experimental data indicate that nicotine does not exhibit all the characteristics of other abused substances, such as psychostimulants and opiates. For example, nicotine is only a weak locomotor enhancer in rats and generally fails to induce a locomotor response in mice. This observation contradicts the general consensus that all drugs of abuse release dopamine in the nucleus accumbens, a subcortical structure, and thus increase locomotor activity in rodents. Because tobacco smoke contains monoamine oxidase inhibitors (MAOIs) and decreases MAO activity in smokers, we have combined MAOIs with nicotine to determine whether it is possible to obtain a locomotor response to nicotine in C57Bl6 mice. Among 15 individual or combined MAOIs, including harmane, norharmane, moclobemide, selegiline, pargyline, clorgyline, tranylcypromine and phenelzine, only irreversible inhibitors of both MAO-A and -B (tranylcypromine, phenelzine, and clorgyline+selegiline) allowed a locomotor response to nicotine. The locomotor stimulant interaction of tranylcypromine and nicotine was absent in beta2-nicotinic acetylcholine receptor subunit knockout mice. Finally, it was found that, whereas naïve rats did not readily self-administer nicotine (10 microg/kg/injection), a robust self-administration of nicotine occurred when animals were pretreated with tranylcypromine (3 mg/kg). Our data suggest that MAOIs contained in tobacco and tobacco smoke act in synergy with nicotine to enhance its rewarding effects.
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Inibidores da Monoaminoxidase/farmacologia , Atividade Motora/efeitos dos fármacos , Nicotina/farmacologia , Recompensa , Animais , Relação Dose-Resposta a Droga , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Atividade Motora/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores Nicotínicos/deficiência , Receptores Nicotínicos/fisiologia , AutoadministraçãoRESUMO
Alcohol-dependence is a chronic disease with a dramatic and expensive social impact. Previous studies have indicated that the blockade of two monoaminergic receptors, α1b-adrenergic and 5-HT2A, could inhibit the development of behavioral sensitization to drugs of abuse, a hallmark of drug-seeking and drug-taking behaviors in rodents. Here, in order to develop a potential therapeutic treatment of alcohol dependence in humans, we have blocked these two monoaminergic receptors by a combination of antagonists already approved by Health Agencies. We show that the association of ifenprodil (1 mg/kg) and cyproheptadine (1 mg/kg) (α1-adrenergic and 5-HT2 receptor antagonists marketed as Vadilex ® and Periactine ® in France, respectively) blocks behavioral sensitization to amphetamine in C57Bl6 mice and to alcohol in DBA2 mice. Moreover, this combination of antagonists inhibits alcohol intake in mice habituated to alcohol (10% v/v) and reverses their alcohol preference. Finally, in order to verify that the effect of ifenprodil was not due to its anti-NMDA receptors property, we have shown that a combination of prazosin (0.5 mg/kg, an α1b-adrenergic antagonist, Mini-Press ® in France) and cyproheptadine (1 mg/kg) could also reverse alcohol preference. Altogether these findings strongly suggest that combined prazosin and cyproheptadine could be efficient as a therapy to treat alcoholism in humans. Finally, because α1b-adrenergic and 5-HT2A receptors blockade also inhibits behavioral sensitization to psychostimulants, opioids and tobacco, it cannot be excluded that this combination will exhibit some efficacy in the treatment of addiction to other abused drugs.
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Antagonistas de Receptores Adrenérgicos alfa 1/farmacologia , Comportamento Animal/efeitos dos fármacos , Receptor 5-HT2A de Serotonina/metabolismo , Antagonistas do Receptor 5-HT2 de Serotonina/farmacologia , Antagonistas de Receptores Adrenérgicos alfa 1/uso terapêutico , Alcoolismo/tratamento farmacológico , Alcoolismo/metabolismo , Alcoolismo/patologia , Anfetamina/farmacologia , Animais , Ciproeptadina/farmacologia , Ciproeptadina/uso terapêutico , Etanol/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Piperidinas/farmacologia , Piperidinas/uso terapêutico , Prazosina/farmacologia , Prazosina/uso terapêutico , Receptor 5-HT2A de Serotonina/química , Antagonistas do Receptor 5-HT2 de Serotonina/uso terapêuticoRESUMO
It was found recently that locomotor and rewarding effects of psychostimulants and opiates were dramatically decreased or suppressed in mice lacking alpha1b-adrenergic receptors [alpha1b-adrenergic receptor knock-outs (alpha1bAR-KOs)] (Drouin et al., 2002). Here we show that blunted locomotor responses induced by 3 and 6 mg/kg d-amphetamine in alpha1bAR-KO mice [-84 and -74%, respectively, when compared with wild-type (WT) mice] are correlated with an absence of d-amphetamine-induced increase in extracellular dopamine (DA) levels in the nucleus accumbens of alpha1bAR-KO mice. Moreover, basal extracellular DA levels in the nucleus accumbens are lower in alpha1bAR-KO than in WT littermates (-28%; p < 0.001). In rats however, prazosin, an alpha1-adrenergic antagonist, decreases d-amphetamine-induced locomotor hyperactivity without affecting extracellular DA levels in the nucleus accumbens, a finding related to the presence of an important nonfunctional release of DA (Darracq et al., 1998). We show here that local d-amphetamine releases nonfunctional DA with the same affinity but a more than threefold lower amplitude in C57BL6/J mice than in Sprague Dawley rats. Altogether, this suggests that a trans-synaptic mechanism amplifies functional DA into nonfunctional DA release. Our data confirm the presence of a powerful coupling between noradrenergic and dopaminergic neurons through the stimulation of alpha1b-adrenergic receptors and indicate that nonfunctional DA release is critical in the interpretation of changes in extracellular DA levels. These results suggest that alpha1b-adrenergic receptors may be important therapeutic pharmacological targets not only in addiction but also in psychosis because most neuroleptics possess anti-alpha1-adrenergic properties.
Assuntos
Dextroanfetamina/farmacologia , Dopamina/metabolismo , Espaço Extracelular/metabolismo , Núcleo Accumbens/efeitos dos fármacos , Receptores Adrenérgicos alfa 1/deficiência , Animais , Comportamento Animal/efeitos dos fármacos , Dopamina/análise , Relação Dose-Resposta a Droga , Espaço Extracelular/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microdiálise , Atividade Motora/efeitos dos fármacos , Núcleo Accumbens/citologia , Núcleo Accumbens/metabolismo , Perfusão , Ratos , Ratos Sprague-Dawley , Receptores Adrenérgicos alfa 1/genética , Especificidade da EspécieRESUMO
Drugs of abuse, such as psychostimulants and opiates, are generally considered as exerting their locomotor and rewarding effects through an increased dopaminergic transmission in the nucleus accumbens. Noradrenergic transmission may also be implicated because most psychostimulants increase norepinephrine (NE) release, and numerous studies have indicated interactions between noradrenergic and dopaminergic neurons through alpha1-adrenergic receptors. However, analysis of the effects of psychostimulants after either destruction of noradrenergic neurons or pharmacological blockade of alpha1-adrenergic receptors led to conflicting results. Here we show that the locomotor hyperactivities induced by d-amphetamine (1-3 mg/kg), cocaine (5-20 mg/kg), or morphine (5-10 mg/kg) in mice lacking the alpha1b subtype of adrenergic receptors were dramatically decreased when compared with wild-type littermates. Moreover, behavioral sensitizations induced by d-amphetamine (1-2 mg/kg), cocaine (5-15 mg/kg), or morphine (7.5 mg/kg) were also decreased in knock-out mice when compared with wild-type. Ruling out a neurological deficit in knock-out mice, both strains reacted similarly to novelty, to intraperitoneal saline, or to the administration of scopolamine (1 mg/kg), an anti-muscarinic agent. Finally, rewarding properties could not be observed in knock-out mice in an oral preference test (cocaine and morphine) and conditioned place preference (morphine) paradigm. Because catecholamine tissue levels, autoradiography of D1 and D2 dopaminergic receptors, and of dopamine reuptake sites and locomotor response to a D1 agonist showed that basal dopaminergic transmission was similar in knock-out and wild-type mice, our data indicate a critical role of alpha1b-adrenergic receptors and noradrenergic transmission in the vulnerability to addiction.
Assuntos
Estimulantes do Sistema Nervoso Central/farmacologia , Atividade Motora/efeitos dos fármacos , Entorpecentes/farmacologia , Receptores Adrenérgicos alfa 1/fisiologia , Recompensa , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Antagonistas Adrenérgicos alfa/metabolismo , Antagonistas Adrenérgicos alfa/farmacocinética , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Comportamento de Escolha/efeitos dos fármacos , Cocaína/farmacologia , Cruzamentos Genéticos , Dextroanfetamina/farmacologia , Dopamina/metabolismo , Agonistas de Dopamina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos , Camundongos Knockout , Morfina/farmacologia , Atividade Motora/fisiologia , Antagonistas Muscarínicos/farmacologia , Norepinefrina/metabolismo , Prazosina/farmacologia , Receptores Adrenérgicos alfa 1/deficiência , Receptores Adrenérgicos alfa 1/genética , Receptores de Dopamina D1/agonistas , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Transtornos Relacionados ao Uso de Substâncias/etiologia , Transtornos Relacionados ao Uso de Substâncias/metabolismo , Transmissão Sináptica/fisiologiaRESUMO
Drugs of abuse, such as D-amphetamine or nicotine, are generally considered as acting through an increased release of dopamine in a subcortical structure, the nucleus accumbens, thus inducing locomotor hyperactivity in rats. Following repeated treatments, the same drugs induce a progressive increase in locomotor response called behavioral sensitization. This process has been suggested to play a role in the acquisition and maintenance of addictive behaviors. Here we show that whereas behavioral sensitization to D-amphetamine (0.5 and 0.75 mg/kg) stays constant following three consecutive periods of withdrawal (15, 30 and 30 days), the same experimental conditions completely abolish behavioral sensitization to 0.3 and 0.5 mg/kg nicotine. Indeed, following these periods of withdrawal, locomotor responses to nicotine are identical to those obtained at the first nicotine injection or after repeated saline injections. However, when a monoamine oxidases inhibitor (MAOI), tranylcypromine (3 mg/kg) or pargyline (30 mg/kg), is co-injected with nicotine, behavioral sensitization is maintained despite submission of the animals to the same withdrawal experimental design. Since tobacco smoke is known to contain many compounds including MAOIs, our data suggest that addictive properties of tobacco may not be limited to nicotine. We propose that MAOIs potentiate effects of nicotine on monoamines release.
Assuntos
Comportamento Animal/efeitos dos fármacos , Inibidores da Monoaminoxidase/farmacologia , Nicotina/farmacologia , Agonistas Nicotínicos/farmacologia , Animais , Estimulantes do Sistema Nervoso Central/farmacologia , Dextroanfetamina/farmacologia , Interações Medicamentosas , Masculino , Atividade Motora/efeitos dos fármacos , Pargilina/farmacologia , Ratos , Ratos Sprague-Dawley , Tranilcipromina/farmacologiaRESUMO
Recent neurobiological data have indicated that almost all drugs of abuse (amphetamine, cocaine, morphine, heroin, cannabis...) increase dopamine release in a sub-cortical structure, the nucleus accumbens. This nucleus is part of different cerebral structures, named "reward system" which constantly defines physical and mental states of an individual. Development of addiction would be due to the modification, by drugs of abuse, of the kinetic and the amplitude of dopamine release. Such a dysregulation would induce the addict to artificially memorize any event linked to the product consumption.
Assuntos
Dopamina/fisiologia , Transtornos Relacionados ao Uso de Substâncias/etiologia , Estimulantes do Sistema Nervoso Central/farmacologia , Humanos , Entorpecentes/farmacologiaRESUMO
RATIONALE: The aim of this paper is to provide evidence for the hypothesis that posttraumatic stress disorder (PTSD) and drug addiction rely on common processes. OBJECTIVE: Our objective is to show that a noradrenergic-dependent behavioral sensitization occurs after the development of PTSD, in a way similar to that recently demonstrated after repeated drug injections. METHODS: Rats classified into high and low responders to novelty (HR/LR) were subjected to a single prolonged stress (SPS). Cross-sensitization was evaluated after d-amphetamine injection (1.0 mg/kg) in a locomotor activity test given either 4, 15, or 90 days later. To determine the involvement of the noradrenergic system, rats were injected with the α2-receptor agonist, clonidine (20 µg/kg), during the SPS. Subsequently, their auditory startle response (ASR) and cross-sensitization were assessed. RESULTS: SPS affected both the hypothalamic-pituitary-adrenal axis and the ASR, replicating some PTSD-like symptoms. Behavioral sensitization was found after 15, 21, and 90 days after the SPS in LR rats, and a behavioral desensitization in HR rats after 15 days. Clonidine delivered during the SPS prevented the behavioral sensitization in LR rats, as well as the effects on ASR in HR and LR rats. CONCLUSIONS: Exposure to SPS is shown to affect behavior and induce a behavioral sensitization to d-amphetamine that is modulated by individual differences. Both of these effects depend on the noradrenergic system. Altogether, the present results (1) replicate findings obtained after repeated drug exposure and (2) strengthen our hypothesis of a common physiological basis between PTSD and drug addiction.
Assuntos
Dextroanfetamina/farmacologia , Norepinefrina/metabolismo , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Transtornos Relacionados ao Uso de Substâncias/fisiopatologia , Animais , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Clonidina/farmacologia , Sistema Hipotálamo-Hipofisário/metabolismo , Masculino , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Sistema Hipófise-Suprarrenal/metabolismo , Ratos , Ratos Sprague-Dawley , Reflexo de Sobressalto/efeitos dos fármacos , Reflexo de Sobressalto/fisiologia , Fatores de TempoRESUMO
Repeated traumatic events induce long-lasting behavioral changes that are key to organism adaptation and that affect cognitive, emotional, and social behaviors. Rodents subjected to repeated instances of aggression develop enduring social aversion and increased anxiety. Such repeated aggressions trigger a stress response, resulting in glucocorticoid release and activation of the ascending dopamine (DA) system. We bred mice with selective inactivation of the gene encoding the glucocorticoid receptor (GR) along the DA pathway, and exposed them to repeated aggressions. GR in dopaminoceptive but not DA-releasing neurons specifically promoted social aversion as well as dopaminergic neurochemical and electrophysiological neuroadaptations. Anxiety and fear memories remained unaffected. Acute inhibition of the activity of DA-releasing neurons fully restored social interaction in socially defeated wild-type mice. Our data suggest a GR-dependent neuronal dichotomy for the regulation of emotional and social behaviors, and clearly implicate GR as a link between stress resiliency and dopaminergic tone.