RESUMO
The ventral pallidum (VP) receives its primary inputs from the nucleus accumbens (NAC) and the basolateral amygdala (BLA). We demonstrated recently that in the VP, the D2 DA receptor (D2R) agonist quinpirole dose-dependently facilitates memory consolidation in inhibitory avoidance and spatial learning. In the VP, D2R can be found both on NAC and BLA terminals. According to our hypothesis, quinpirole microinjected into the VP can facilitate memory consolidation via modulation of synaptic plasticity on NAC and/or BLA terminals. The effect of intra-VP quinpirole on BLA-VP and NAC shell-VP synapses was investigated via a high frequency stimulation (HFS) protocol. Quinpirole was administered in three doses into the VP of male Sprague-Dawley rats after HFS; controls received vehicle. To examine whether an interaction between the NAC shell and the BLA at the level of the VP was involved, tetrodotoxin (TTX) was microinjected into one of the nuclei while stimulating the other nucleus. Our results showed that quinpirole dose-dependently modulates BLA-VP and NAC shell-VP synapses, similar to those observed in inhibitory avoidance and spatial learning, respectively. The lower dose inhibits BLA inputs, while the larger doses facilitates NAC shell inputs. The experiments with TTX demonstrates that the two nuclei do not influence each others' evoked responses in the VP. Power spectral density analysis demonstrated that independent from the synaptic facilitation, intra-VP quinpirole increases the amplitude of gamma frequency band after NAC HFS, and BLA tonically suppresses the NAC's HFS-induced gamma facilitation. In contrast, HFS of the BLA results in a delayed, transient increase in the amplitude of the gamma frequency band correlating with the LTP of the P1 component of the VP response to BLA stimulation. Furthermore, our results demonstrate that the BLA plays a prominent role in the generation of the delta oscillations: HFS of the BLA leads to a gradually increasing delta frequency band facilitation over time, while BLA inhibition blocks the NAC's HFS induced strong delta facilitation. These findings demonstrate that there is a complex interaction between the NAC shell region and the VP, as well as the BLA and the VP, and support the important role of VP D2Rs in the regulation of limbic information flow.
Assuntos
Prosencéfalo Basal , Agonistas de Dopamina , Relação Dose-Resposta a Droga , Microinjeções , Quimpirol , Ratos Sprague-Dawley , Receptores de Dopamina D2 , Animais , Quimpirol/farmacologia , Masculino , Prosencéfalo Basal/efeitos dos fármacos , Prosencéfalo Basal/fisiologia , Receptores de Dopamina D2/agonistas , Receptores de Dopamina D2/efeitos dos fármacos , Ratos , Agonistas de Dopamina/farmacologia , Agonistas de Dopamina/administração & dosagem , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/fisiologia , Sistema Límbico/efeitos dos fármacos , Sistema Límbico/fisiologia , Estimulação Elétrica , Complexo Nuclear Basolateral da Amígdala/efeitos dos fármacos , Complexo Nuclear Basolateral da Amígdala/fisiologiaRESUMO
RATIONALE: Antipsychotic medications that are used to treat psychosis are often limited in their efficacy by high rates of severe side effects. Treatment success in schizophrenia is further complicated by high rates of comorbid nicotine use. Dopamine D2 heteroreceptor complexes have recently emerged as targets for the development of more efficacious pharmaceutical treatments for schizophrenia. OBJECTIVE: The current study sought to explore the use of the positive allosteric modulator of the mGlu5 receptor 3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) as a treatment to reduce symptoms related to psychosis and comorbid nicotine use. METHODS: Neonatal treatment of animals with the dopamine D2-like receptor agonist quinpirole (NQ) from postnatal day (P)1-21 produces a lifelong increase in D2 receptor sensitivity, showing relevance to psychosis and comorbid tobacco use disorder. Following an 8-day conditioning paradigm, brain tissue in the mesolimbic pathway was analyzed for several plasticity markers, including brain derived neurotrophic factor (BDNF), phosphorylated p70 ribosomal S6 kinase (phospho-p70S6K), and cadherin-13 (Cdh13). RESULTS: Pretreatment with CDPPB was effective to block enhanced nicotine conditioned place preference observed in NQ-treated animals. Pretreatment was additionally effective to block the nicotine-induced increase in BDNF and sex-dependent increases in cadherin-13 in the ventral tegmental area (VTA), as well as increased phospho-p70S6K in the nucleus accumbens (NAcc) shell found in NQ-treated animals. CONCLUSION: In conjunction with prior work, the current study suggests positive allosteric modulation of the mGlu5 receptor, an emerging target for schizophrenia therapeutics, may be effective for the treatment of comorbid nicotine abuse in psychosis.
Assuntos
Benzamidas , Nicotina , Receptor de Glutamato Metabotrópico 5 , Recompensa , Animais , Nicotina/farmacologia , Masculino , Benzamidas/farmacologia , Benzamidas/uso terapêutico , Receptor de Glutamato Metabotrópico 5/metabolismo , Ratos , Plasticidade Neuronal/efeitos dos fármacos , Fumar Cigarros , Feminino , Quimpirol/farmacologia , Pirazóis/farmacologia , Ratos Sprague-Dawley , Transtornos Psicóticos/tratamento farmacológico , Transtornos Psicóticos/metabolismo , Regulação Alostérica/efeitos dos fármacos , Sistema Límbico/metabolismo , Sistema Límbico/efeitos dos fármacos , Animais Recém-Nascidos , Núcleo Accumbens/metabolismo , Núcleo Accumbens/efeitos dos fármacosRESUMO
Cotinine is the major metabolite of nicotine and has recently been shown to be self-administered intravenously by rats. However, mechanisms underlying cotinine self-administration remained unknown. Mesolimbic dopamine system projecting from the ventral tegmental area (VTA) to nucleus accumbens (NAC) is closely implicated in drug reinforcement, including nicotine. The objective of the current study was to determine potential involvement of mesolimbic dopamine system in cotinine self-administration. An intracranial self-administration experiment demonstrates that cotinine at 0.88 and 1.76 ng/100 nl/infusion was self-infused into the VTA by rats. Rats produced more infusions of cotinine than vehicle and responded more on active than inactive lever during acquisition, reduced responding when cotinine was replaced by vehicle, and resumed responding during re-exposure to cotinine. Microinjection of cotinine at 1.76 ng/100 nl/infusion into the VTA increased extracellular dopamine levels within the NAC. Subcutaneous injection of cotinine at 1 mg/kg also increased extracellular dopamine levels within the NAC. Administration of the D1-like receptor antagonist SCH 23390 attenuated intravenous cotinine self-administration. On the other hand, bupropion, a catecholamine uptake inhibitor, did not significantly alter intravenous cotinine self-administration. These results suggest that activation of mesolimbic dopamine system may represent one cellular mechanism underlying cotinine self-administration. This shared mechanism between cotinine and nicotine suggests that cotinine may play a role in nicotine reinforcement.
Assuntos
Cotinina/administração & dosagem , Dopamina/fisiologia , Sistema Límbico/fisiologia , Autoadministração , Animais , Benzazepinas/antagonistas & inibidores , Encéfalo/metabolismo , Bupropiona , Inibidores da Captação de Dopamina , Sistema Límbico/efeitos dos fármacos , Masculino , Microinjeções , Núcleo Accumbens/efeitos dos fármacos , Ratos , Reforço Psicológico , Área Tegmentar Ventral/efeitos dos fármacosRESUMO
Psychological stress and occlusal alterations are contributing etiologic factors for temporomandibular and muscular disorders in the orofacial area. The neural modulation recruited for this relationship, however, is not elucidated. The aim of this study was to investigate potential central mechanisms involved in the exodontia-induced occlusal instability associated with unpredictable chronic stress (UCS). Male adult Wistar rats were submitted to occlusal instability (unilateral molar teeth extraction) and/or to a UCS protocol and treated with diazepam or vehicle. The anxiety-like behavior was evaluated by elevated plus maze (EPM) and open field (OF) tests. Limbic structures such as the central nucleus of the amygdala (CeA), paraventricular nucleus of the hypothalamus (PVN), dorsal periaqueductal gray matter (dPAG) and nucleus accumbens core (NAc) were analyzed for expression of FosB/ΔFosB (immediate early genes) by immunohistochemistry. Exodontia and/or UCS decreased the time spent in the open arms at the EPM and the distance travelled at the OF, and increased the immobility time at the OF, suggesting anxiety-like behavior. In addition, exodontia induction resulted in an upregulation of FosB/ΔFosB in the CeA, PVN and dPAG, while UCS and exodontia + UCS upregulate FosB/ΔFosB immunoreactivity in the CeA, PVN, dPAG and NAc. Treatment with diazepam decreased the expression of FosB/ΔFosB in all analyzed structures of animals subject to UCS and exodontia + UCS, while promoted a reduction in the FosB/ΔFosB expression in the CeA, PVN and dPAG in animals subject to exodontia. Our findings showed an anxiogenic effect of exodontia and UCS, which is correlated with intranuclear neuron activation of limbic structures in a spatially dependent manner and that is prevented by the administration of diazepam.
Assuntos
Sistema Límbico/metabolismo , Neurônios/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Estresse Psicológico/metabolismo , Extração Dentária , Animais , Ansiolíticos/farmacologia , Diazepam/farmacologia , Imuno-Histoquímica , Sistema Límbico/efeitos dos fármacos , Masculino , Neurônios/efeitos dos fármacos , Ratos , Ratos Wistar , Regulação para CimaRESUMO
Antipsychotic treatment can produce a dopamine-supersensitive state, potentiating the response to dopamine receptor stimulation. In both schizophrenia patients and rats, this is linked to tolerance to ongoing antipsychotic treatment. In rodents, dopamine supersensitivity is often confirmed by an exaggerated psychomotor response to d-amphetamine after discontinuation of antipsychotic exposure. Here we examined in rats the dopaminergic mechanisms mediating this enhanced behavioural response, as this could uncover pathophysiological processes underlying the expression of antipsychotic-evoked dopamine supersensitivity. Rats received 0.5 mg/kg/day haloperidol via osmotic minipump for 2 weeks, before treatment was discontinued. After cessation of antipsychotic treatment, rats showed a supersensitive psychomotor response to the D2 agonist quinpirole, but not to the D1 partial agonist SKF38393 or the dopamine reuptake blocker GBR12783. Furthermore, acute D1 receptor blockade (using SCH39166) decreased the exaggerated psychomotor response to d-amphetamine in haloperidol-pretreated rats, whereas acute D2 receptor blockade (using sulpiride) enhanced it. Thus, after discontinuation of antipsychotic treatment, D1- and D2-mediated transmission differentially modulate the expression of a supersensitive response to d-amphetamine. This supersensitive behavioural response was accompanied by enhanced GSK3ß activity and suppressed ERK1/2 activity in the nucleus accumbens (but not caudate-putamen), suggesting increased mesolimbic D2 transmission. Finally, after discontinuing haloperidol treatment, neither increasing ventral midbrain dopamine impulse flow nor infusing d-amphetamine into the cerebral ventricles triggered the expression of already established dopamine supersensitivity, suggesting that peripheral effects are required. Thus, while dopamine receptor-mediated signalling regulates the expression of antipsychotic-evoked dopamine supersensitivity, a simple increase in central dopamine neurotransmission is insufficient to trigger this supersensitivity.
Assuntos
Antipsicóticos/efeitos adversos , Dopamina/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Córtex Cerebral/efeitos dos fármacos , Dextroanfetamina/farmacologia , Dopamina/farmacologia , Agonistas de Dopamina/farmacologia , Antagonistas de Dopamina/farmacologia , Inibidores da Captação de Dopamina/farmacologia , Haloperidol/farmacologia , Sistema Límbico/efeitos dos fármacos , Masculino , Atividade Motora/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Receptores de Dopamina D1/agonistas , Receptores de Dopamina D1/antagonistas & inibidores , Receptores de Dopamina D1/efeitos dos fármacos , Receptores de Dopamina D2/efeitos dos fármacosRESUMO
The incidence of chronic pain is high in the general population and it is closely related to anxiety disorders, which promote negative effects on the quality of life. The cannabinoid system has essential participation in the pain sensitivity circuit. In this perspective, cannabidiol (CBD) is considered a promising strategy for treating neuropathic pain. Our study aimed to evaluate the effects of sub-chronic systemic treatment with CBD (0.3, 3, 10, or 30 mg/kg, i.p.) in male in rats submitted to chronic constriction injury of the sciatic nerve (CCI) or not (SHAM) and assessed in nociceptive tests (von Frey, acetone, and hot plate, three days CBD's treatment) and in the open field test (OFT, two days CBD's treatment). We performed a screening immunoreactivity of CB1 and TRPV1 receptors in cortical and limbic regions tissues, which were collected after 1.5 h of behavioral tests on the 24th experimental day. This study presents a dose-response curve to understand better the effects of low doses (3 mg/kg) on CBD's antiallodynic and anxiolytic effects. Also, low doses of CBD were able to (1) reverse mechanical and thermal allodynia (cold) and hyperalgesia, (2) reverse anxious behaviors (reduction of the % of grooming and freezing time, and increase of the % of center time in the OFT) induced by chronic pain. The peripheral neuropathy promoted the increase in the expression of CB1 and TRPV1 receptors in the anterior cingulate cortex (ACC), anterior insular cortex (AIC), basolateral amygdala (BLA), dorsal hippocampus (DH), and ventral hippocampus (VH). CBD potentiated this effect in the ACC, AIC, BLA, DH, and VH regions. These results provide substantial evidence of the role of the ACC-AIC-BLA corticolimbic circuit, and BLA-VH for pain regulation. These results can be clinically relevant since they contribute to the evidence of CBD's beneficial effects on treating chronic pain and associated comorbidities such as anxiety.
Assuntos
Ansiedade/tratamento farmacológico , Canabidiol/uso terapêutico , Hiperalgesia/tratamento farmacológico , Neuralgia/tratamento farmacológico , Receptor CB1 de Canabinoide/efeitos dos fármacos , Canais de Cátion TRPV/efeitos dos fármacos , Animais , Ansiedade/psicologia , Córtex Cerebral/metabolismo , Hipocampo/metabolismo , Temperatura Alta , Sistema Límbico/efeitos dos fármacos , Masculino , Rede Nervosa/efeitos dos fármacos , Neuralgia/metabolismo , Neuralgia/psicologia , Medição da Dor/efeitos dos fármacos , Estimulação Física , Ratos , Ratos Wistar , Ciática/tratamento farmacológicoRESUMO
Adolescent drinking is risky because neural circuits in the frontal lobes are undergoing maturational processes important for cognitive function and behavioral control in adulthood. Previous studies have shown that myelinated axons in the medial prefrontal cortex (mPFC) are particularly sensitive to alcohol drinking, especially in males. Pro-inflammatory mediators like toll-like receptor 4 (TLR4) and interleukin-1 beta (IL1b) have been implicated in alcohol induced-inflammation and demyelination; thus, herein we test the hypothesis that voluntary alcohol drinking early in adolescence elicits a pro-inflammatory state that is more pronounced in the brain of males compared to females. Adolescent male and female Wistar rats self-administered sweetened alcohol or sweetened water from postnatal days 28-42 and separate sets of brains were processed for 1) immunolabeling for ionized calcium-binding adapter molecule 1 to analyze microglial cell morphology, or 2) qPCR analysis of gene expression of pro-inflammatory mediators. Binge drinking alcohol activated microglia in the mPFC and hippocampus of both males and females, suggesting that voluntary alcohol exposure initiates an inflammatory response. Il1b mRNA was upregulated in the mPFC of both sexes. Conversely, Tlr4 mRNA levels were elevated after drinking only in males, which could explain more robust effects of alcohol on myelin in this region in developing males compared to females. Il1b mRNA changes were not observed in the hippocampus, but alcohol elevated Tlr4 mRNA in both sexes, highlighting regional specificity in inflammatory responses to alcohol. Overall, these findings give insight into potential mechanisms by which low-to-moderate voluntary alcohol intake impacts the developing brain. This article is part of the special Issue on 'Vulnerabilities to Substance Abuse'.
Assuntos
Consumo de Bebidas Alcoólicas/genética , Consumo de Bebidas Alcoólicas/patologia , Interleucina-1beta/genética , Sistema Límbico/metabolismo , Receptor 4 Toll-Like/genética , Consumo de Bebidas Alcoólicas/psicologia , Animais , Consumo Excessivo de Bebidas Alcoólicas/genética , Consumo Excessivo de Bebidas Alcoólicas/psicologia , Condicionamento Operante , Feminino , Regulação da Expressão Gênica , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Interleucina-1beta/efeitos dos fármacos , Sistema Límbico/efeitos dos fármacos , Masculino , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Ratos , Ratos Wistar , Autoadministração , Caracteres Sexuais , Receptor 4 Toll-Like/efeitos dos fármacosRESUMO
Importance: Altered functional connectivity (FC) is a common finding in resting-state functional magnetic resonance imaging (rs-fMRI) studies of people with psychosis, yet how FC disturbances evolve in the early stages of illness, and how antipsychotic treatment influences these disturbances, remains unknown. Objective: To investigate longitudinal FC changes in antipsychotic-naive and antipsychotic-treated patients with first-episode psychosis (FEP). Design, Setting, and Participants: This secondary analysis of a triple-blind, randomized clinical trial was conducted over a 5-year recruitment period between April 2008 and December 2016 with 59 antipsychotic-naive patients with FEP receiving either a second-generation antipsychotic or a placebo pill over a treatment period of 6 months. Participants were required to have low suicidality and aggression, to have a duration of untreated psychosis of less than 6 months, and to be living in stable accommodations with social support. Both FEP groups received intensive psychosocial therapy. A healthy control group was also recruited. Participants completed rs-fMRI scans at baseline, 3 months, and 12 months. Data were analyzed from May 2019 to August 2020. Interventions: Resting-state functional MRI was used to probe brain FC. Patients received either a second-generation antipsychotic or a matched placebo tablet. Both patient groups received a manualized psychosocial intervention. Main Outcomes and Measures: The primary outcomes of this analysis were to investigate (1) FC differences between patients and controls at baseline; (2) FC changes in medicated and unmedicated patients between baseline and 3 months; and (3) associations between longitudinal FC changes and clinical outcomes. An additional aim was to investigate long-term FC changes at 12 months after baseline. These outcomes were not preregistered. Results: Data were analyzed for 59 patients (antipsychotic medication plus psychosocial treatment: 28 [47.5%]; mean [SD] age, 19.5 [3.0] years; 15 men [53.6%]; placebo plus psychosocial treatment: 31 [52.5%]; mean [SD] age, 18.8 [2.7]; 16 men [51.6%]) and 27 control individuals (mean [SD] age, 21.9 [1.9] years). At baseline, patients showed widespread functional dysconnectivity compared with controls, with reductions predominantly affecting interactions between the default mode network, limbic systems, and the rest of the brain. From baseline to 3 months, patients receiving placebo showed increased FC principally within the same systems; some of these changes correlated with improved clinical outcomes (canonical correlation analysis R = 0.901; familywise error-corrected P = .005). Antipsychotic exposure was associated with increased FC primarily between the thalamus and the rest of the brain. Conclusions and Relevance: In this secondary analysis of a clinical trial, antipsychotic-naive patients with FEP showed widespread functional dysconnectivity at baseline, followed by an early normalization of default mode network and cortical limbic dysfunction in patients receiving placebo and psychosocial intervention. Antipsychotic exposure was associated with FC changes concentrated on thalamocortical networks. Trial Registration: ACTRN12607000608460.
Assuntos
Antipsicóticos/farmacologia , Encéfalo , Conectoma , Rede de Modo Padrão , Rede Nervosa , Transtornos Psicóticos , Adolescente , Adulto , Agressão/fisiologia , Antipsicóticos/administração & dosagem , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Encéfalo/fisiopatologia , Rede de Modo Padrão/diagnóstico por imagem , Rede de Modo Padrão/efeitos dos fármacos , Rede de Modo Padrão/fisiopatologia , Método Duplo-Cego , Feminino , Humanos , Sistema Límbico/diagnóstico por imagem , Sistema Límbico/efeitos dos fármacos , Sistema Límbico/fisiopatologia , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/efeitos dos fármacos , Rede Nervosa/fisiopatologia , Avaliação de Resultados em Cuidados de Saúde , Transtornos Psicóticos/diagnóstico por imagem , Transtornos Psicóticos/tratamento farmacológico , Transtornos Psicóticos/fisiopatologia , Risco , Comportamento Autodestrutivo/fisiopatologia , Adulto JovemRESUMO
BACKGROUND: Altered monoamine (i.e., serotonin, dopamine, and norepinephrine) activity following episodes of alcohol abuse plays key roles not only in the motivation to ingest ethanol, but also physiological dysfunction related to its misuse. Although monoamine activity is essential for physiological processes that require coordinated communication across the gut-brain axis (GBA), relatively little is known about how alcohol misuse may affect monoamine levels across the GBA. Therefore, we evaluated monoamine activity across the mouse gut and brain following episodes of binge-patterned ethanol drinking. METHODS: Monoamine and select metabolite neurochemical concentrations were analyzed by ultra-high-performance liquid chromatography in gut and brain regions of female and male C57BL/6J mice following "Drinking in the Dark" (DID), a binge-patterned ethanol ingestion paradigm. RESULTS: First, we found that alcohol access had an overall small effect on gut monoamine-related neurochemical concentrations, primarily influencing dopamine activity. Second, neurochemical patterns between the small intestine and the striatum were correlated, adding to recent evidence of modulatory activity between these areas. Third, although alcohol access robustly influenced activity in brain areas in the mesolimbic dopamine system, binge exposure also influenced monoaminergic activity in the hypothalamic region. Finally, sex differences were observed in the concentrations of neurochemicals within the gut, which was particularly pronounced in the small intestine. CONCLUSION: Together, these data provide insights into the influence of alcohol abuse and biological sex on monoamine-related neurochemical changes across the GBA, which could have important implications for GBA function and dysfunction.
Assuntos
Consumo Excessivo de Bebidas Alcoólicas/metabolismo , Eixo Encéfalo-Intestino/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Depressores do Sistema Nervoso Central/farmacologia , Dopamina/metabolismo , Etanol/farmacologia , Intestino Delgado/efeitos dos fármacos , Norepinefrina/metabolismo , Serotonina/metabolismo , Animais , Encéfalo/metabolismo , Ceco/efeitos dos fármacos , Ceco/metabolismo , Cromatografia Líquida de Alta Pressão , Feminino , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Intestino Delgado/metabolismo , Sistema Límbico/efeitos dos fármacos , Sistema Límbico/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Neostriado/efeitos dos fármacos , Neostriado/metabolismo , Fatores SexuaisRESUMO
Cannabis use among pregnant women is increasing worldwide along with permissive sociocultural attitudes toward it. Prenatal cannabis exposure (PCE), however, is associated with adverse outcome among offspring, ranging from reduced birth weight to child psychopathology. We have previously shown that male rat offspring prenatally exposed to Δ9-tetrahydrocannabinol (THC), a rat model of PCE, exhibit extensive molecular, cellular, and synaptic changes in dopamine neurons of the ventral tegmental area (VTA), resulting in a susceptible mesolimbic dopamine system associated with a psychotic-like endophenotype. This phenotype only reveals itself upon a single exposure to THC in males but not females. Here, we characterized the impact of PCE on female behaviors and mesolimbic dopamine system function by combining in vivo single-unit extracellular recordings in anesthetized animals and ex vivo patch clamp recordings, along with neurochemical and behavioral analyses. We find that PCE female offspring do not show any spontaneous or THC-induced behavioral disease-relevant phenotypes. The THC-induced increase in dopamine levels in nucleus accumbens was reduced in PCE female offspring, even when VTA dopamine activity in vivo and ex vivo did not differ compared to control. These findings indicate that PCE impacts mesolimbic dopamine function and its related behavioral domains in a sex-dependent manner and warrant further investigations to decipher the mechanisms determining this sex-related protective effect from intrauterine THC exposure.
Assuntos
Comportamento Animal/efeitos dos fármacos , Dopamina/metabolismo , Dronabinol/toxicidade , Sistema Límbico/efeitos dos fármacos , Efeitos Tardios da Exposição Pré-Natal/patologia , Área Tegmentar Ventral/efeitos dos fármacos , Animais , Feminino , Alucinógenos/toxicidade , Sistema Límbico/patologia , Gravidez , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Ratos , Ratos Sprague-Dawley , Área Tegmentar Ventral/patologiaRESUMO
Fear extinction is defined as decline in conditioned fear responses that occurs with repeated and non-reinforced exposure to a feared conditioned stimulus. Experimental evidence suggests that the extinction of fear memory requires the integration of the medial prefrontal cortex (mPFC); nevertheless, the role of its sub-regions in regulating the expression and extinction of auditory fear has been rarely addressed in literature. The present study examined the roles of the infra-limbic (IL) and pre-limbic (PL) regions of the mPFC in the expression and extinction of auditory fear by temporally deactivating these regions using lidocaine (10 µg/0.5 µl) before training male Wistar rats in auditory fear-conditioning tasks. The results showed increased freezing levels and impaired extinction through deactivating the IL rather than the PL cortex. Given the role of the dopaminergic pathways in regulating fear memory, this study also investigated the role of D2 receptors located in the IL cortex in fear extinction. Fear extinction was improved in an inverted U-shape pattern through the intra-IL infusion of 15.125, 31.25, 62.5, 125, 250 and 500 ng/0.5 µl of the D2 receptor antagonist sulpiride. In other words, the moderate doses, i.e. 31.25, 62.5, 125, 250 ng/0.5 µl, enhanced auditory fear extinction, whereas the lowest and highest doses, i.e. 15.125 and 500 ng/0.5 µl, were ineffective. These findings demonstrated the key roles of the IL cortex and its dopamine D2 receptors in regulating auditory fear in rats.
Assuntos
Antagonistas dos Receptores de Dopamina D2/administração & dosagem , Extinção Psicológica/efeitos dos fármacos , Medo/efeitos dos fármacos , Lidocaína/administração & dosagem , Sistema Límbico/metabolismo , Córtex Pré-Frontal/metabolismo , Receptores de Dopamina D2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sulpirida/administração & dosagem , Animais , Condicionamento Clássico/efeitos dos fármacos , Sistema Límbico/efeitos dos fármacos , Masculino , Córtex Pré-Frontal/efeitos dos fármacos , Ratos , Ratos WistarRESUMO
Ketamine produces a rapid antidepressant response in over 50% of adults with treatment-resistant depression. A long infusion of ketamine may provide durable remission of depressive symptoms, but the safety, efficacy, and neurobiological correlates are unknown. In this open-label, proof-of-principle study, adults with treatment-resistant depression (N = 23) underwent a 96-h infusion of intravenous ketamine (0.15 mg/kg/h titrated toward 0.6 mg/kg/h). Clonidine was co-administered to reduce psychotomimetic effects. We measured clinical response for 8 weeks post-infusion. Resting-state functional magnetic resonance imaging was used to assess functional connectivity in patients pre- and 2 weeks post-infusion and in matched non-depressed controls (N = 27). We hypothesized that responders to therapy would demonstrate response-dependent connectivity changes while all subjects would show treatment-dependent connectivity changes. Most participants completed infusion (21/23; mean final dose 0.54 mg/kg/h, SD 0.13). The infusion was well tolerated with minimal cognitive and psychotomimetic side effects. Depressive symptoms were markedly reduced (MADRS 29 ± 4 at baseline to 9 ± 8 one day post-infusion), which was sustained at 2 weeks (13 ± 8) and 8 weeks (15 ± 8). Imaging demonstrated a response-dependent decrease in hyperconnectivity of the subgenual anterior cingulate cortex to the default mode network, and a treatment-dependent decrease in hyperconnectivity within the limbic system (hippocampus, amygdala, medial thalamus, nucleus accumbens). In exploratory analyses, connectivity was increased between the limbic system and frontal areas, and smaller right hippocampus volume at baseline predicted larger MADRS change. A single prolonged infusion of ketamine provides a tolerated, rapid, and sustained response in treatment-resistant depression and normalizes depression-related hyperconnectivity in the limbic system and frontal lobe. ClinicalTrials.gov : Treatment Resistant Depression (Pilot), NCT01179009.
Assuntos
Antidepressivos/uso terapêutico , Transtorno Depressivo Resistente a Tratamento/tratamento farmacológico , Ketamina/uso terapêutico , Sistema Límbico/efeitos dos fármacos , Adolescente , Adulto , Idoso , Antidepressivos/administração & dosagem , Clonidina/uso terapêutico , Transtorno Depressivo Resistente a Tratamento/diagnóstico por imagem , Transtorno Depressivo Resistente a Tratamento/psicologia , Feminino , Giro do Cíngulo/efeitos dos fármacos , Alucinógenos/efeitos adversos , Humanos , Infusões Intravenosas , Ketamina/administração & dosagem , Ketamina/antagonistas & inibidores , Sistema Límbico/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/efeitos dos fármacos , Escalas de Graduação Psiquiátrica , Simpatolíticos/uso terapêutico , Resultado do Tratamento , Adulto JovemRESUMO
Post-traumatic stress disorder (PTSD) is characterized by hypervigilance, increased reactivity to unpredictable versus predictable threat signals, deficits in fear extinction, and an inability to discriminate between threat and safety. First-line pharmacotherapies for psychiatric disorders have limited therapeutic efficacy in PTSD. However, recent studies have advanced our understanding of the roles of several limbic neuropeptides in the regulation of defensive behaviors and in the neural processes that are disrupted in PTSD. For example, preclinical studies have shown that blockers of tachykinin pathways, such as the Tac2 pathway, attenuate fear memory consolidation in mice and thus might have unique potential as early post-trauma interventions to prevent PTSD development. Targeting this pathway might also be beneficial in regulating other symptoms of PTSD, including trauma-induced aggressive behavior. In addition, preclinical and clinical studies have shown the important role of angiotensin receptors in fear extinction and the promise of using angiotensin II receptor blockade to reduce PTSD symptom severity. Additional preclinical studies have demonstrated that the oxytocin receptors foster accurate fear discrimination by facilitating fear responses to predictable versus unpredictable threats. Complementary human imaging studies demonstrate unique neural targets of intranasal oxytocin and compare its efficacy with well-established anxiolytic treatments. Finally, promising data from human subjects have demonstrated that a selective vasopressin 1A receptor antagonist reduces anxiety induced by unpredictable threats. This review highlights these novel promising targets for the treatment of unique core elements of PTSD pathophysiology.
Assuntos
Ansiedade/metabolismo , Emoções/fisiologia , Sistema Límbico/metabolismo , Neuropeptídeos/metabolismo , Transtornos de Estresse Pós-Traumáticos/metabolismo , Animais , Ansiedade/tratamento farmacológico , Ansiedade/psicologia , Emoções/efeitos dos fármacos , Extinção Psicológica/efeitos dos fármacos , Extinção Psicológica/fisiologia , Humanos , Sistema Límbico/efeitos dos fármacos , Rede Nervosa/efeitos dos fármacos , Rede Nervosa/metabolismo , Neuropeptídeos/farmacologia , Neuropeptídeos/uso terapêutico , Receptores de Taquicininas/antagonistas & inibidores , Receptores de Taquicininas/metabolismo , Transtornos de Estresse Pós-Traumáticos/tratamento farmacológico , Transtornos de Estresse Pós-Traumáticos/psicologia , Taquicininas/antagonistas & inibidores , Taquicininas/metabolismoRESUMO
Accumulating evidence has linked pathological changes associated with chronic alcohol exposure to neuroimmune signaling mediated by microglia. Prior characterization of the microglial structure-function relationship demonstrates that alterations in activity states occur concomitantly with reorganization of cellular architecture. Accordingly, gaining a better understanding of microglial morphological changes associated with ethanol exposure will provide valuable insight into how neuroimmune signaling may contribute to ethanol-induced reshaping of neuronal function. Here we have used Iba1-staining combined with high-resolution confocal imaging and 3D reconstruction to examine microglial structure in the prelimbic (PL) cortex and nucleus accumbens (NAc) in male Long-Evans rats. Rats were either sacrificed at peak withdrawal following 15 days of exposure to chronic intermittent ethanol (CIE) or 24 hr after two consecutive injections of the immune activator lipopolysaccharide (LPS), each separated by 24 hr. LPS exposure resulted in dramatic structural reorganization of microglia in the PL cortex, including increased soma volume, overall cellular volume, and branching complexity. In comparison, CIE exposure was associated with a subtle increase in somatic volume and differential effects on microglia processes, which were largely absent in the NAc. These data reveal that microglial activation following a neuroimmune challenge with LPS or exposure to chronic alcohol exhibits distinct morphometric profiles and brain region-dependent specificity.
Assuntos
Etanol/farmacologia , Sistema Límbico/patologia , Lipopolissacarídeos/farmacologia , Microglia/patologia , Núcleo Accumbens/patologia , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Etanol/sangue , Sistema Límbico/efeitos dos fármacos , Masculino , Proteínas dos Microfilamentos/metabolismo , Microglia/efeitos dos fármacos , Núcleo Accumbens/efeitos dos fármacos , Ratos , Ratos Long-Evans , Síndrome de Abstinência a Substâncias/patologiaRESUMO
Psychostimulant use disorder is a major public health issue, and despite the scope of the problem there are currently no Food and Drug Administration (FDA)-approved treatments. There would be tremendous utility in development of a treatment that could help patients both achieve and maintain abstinence. Previous work from our group has identified granulocyte-colony stimulating factor (G-CSF) as a neuroactive cytokine that alters behavioral response to cocaine, increases synaptic dopamine release, and enhances cognitive flexibility. Here, we investigate the role of G-CSF in affecting extinction and reinstatement of cocaine-seeking and perform detailed characterization of its proteomic effects in multiple limbic substructures. Male Sprague Dawley rats were injected with PBS or G-CSF during (1) extinction or (2) abstinence from cocaine self-administration, and drug seeking behavior was measured. Quantitative assessment of changes in the proteomic landscape in the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC) were performed via data-independent acquisition (DIA) mass spectrometry analysis. Administration of G-CSF during extinction accelerated the rate of extinction, and administration during abstinence attenuated cue-induced cocaine-seeking. Analysis of global protein expression demonstrated that G-CSF regulated proteins primarily in mPFC that are critical to glutamate signaling and synapse maintenance. Taken together, these findings support G-CSF as a viable translational research target with the potential to reduce drug craving or seeking behaviors. Importantly, recombinant G-CSF exists as an FDA-approved medication which may facilitate rapid clinical translation. Additionally, using cutting-edge multiregion discovery proteomics analyses, these studies identify a novel mechanism underlying G-CSF effects on behavioral plasticity.SIGNIFICANCE STATEMENT Pharmacological treatments for psychostimulant use disorder are desperately needed, especially given the disease's chronic, relapsing nature. However, there are currently no Food and Drug Administration (FDA)-approved pharmacotherapies. Emerging evidence suggests that targeting the immune system may be a viable translational research strategy; preclinical studies have found that the neuroactive cytokine granulocyte-colony stimulating factor (G-CSF) alters cocaine reward and reinforcement and can enhance cognitive flexibility. Given this basis of evidence we studied the effects of G-CSF treatment on extinction and reinstatement of cocaine seeking. We find that administration of G-CSF accelerates extinction and reduces cue-induced drug seeking after cocaine self-administration. In addition, G-CSF leads to downregulation of synaptic glutamatergic proteins in medial prefrontal cortex (mPFC), suggesting that G-CSF influences drug seeking via glutamatergic mechanisms.
Assuntos
Transtornos Relacionados ao Uso de Cocaína/tratamento farmacológico , Comportamento de Procura de Droga/efeitos dos fármacos , Glutamatos/fisiologia , Fator Estimulador de Colônias de Granulócitos/farmacologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Animais , Transtornos Relacionados ao Uso de Cocaína/psicologia , Fissura/efeitos dos fármacos , Sinais (Psicologia) , Extinção Psicológica/efeitos dos fármacos , Sistema Límbico/efeitos dos fármacos , Masculino , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Proteômica , Ratos , Ratos Sprague-Dawley , Síndrome de Abstinência a Substâncias/tratamento farmacológico , Síndrome de Abstinência a Substâncias/psicologiaRESUMO
BACKGROUND: Psychological stress is a risk factor for irritable bowel syndrome, a functional gastrointestinal pain disorder featuring abnormal brain-gut connectivity. The guanylate cyclase-C (GC-C) agonist linaclotide has been shown to relieve abdominal pain in IBS-C and exhibits antinociceptive effects in rodent models of post-inflammatory visceral hypersensitivity. However, the role GC-C signaling plays in psychological stress-induced visceral hypersensitivity is unknown. Here, we test the hypothesis that GC-C agonism reverses stress-induced colonic hypersensitivity via inhibition of nociceptive afferent signaling resulting in normalization of stress-altered corticotropin-releasing factor (CRF) expression in brain regions involved in pain perception and modulation. METHODS: Adult female rats were exposed to water avoidance stress or sham stress for 10 days, and the effects of linaclotide on stress-induced changes in colonic sensitivity, corticolimbic phospho-extracellular signal-regulated kinase (pERK), and CRF expression were measured using a combination of behavioral assessments, immunohistochemistry, and qRT-PCR. KEY RESULTS: Stressed rats exhibited colonic hypersensitivity and elevated corticolimbic pERK on day 11, which was inhibited by linaclotide. qRT-PCR analysis revealed dysregulated CRF expression in the medial prefrontal cortex, paraventricular nucleus of the hypothalamus, and central nucleus of the amygdala on day 28. Dysregulated CRF expression was not affected by linaclotide treatment. CONCLUSIONS AND INFERENCES: Our results demonstrate that exposure to repeated stress induces chronic colonic hypersensitivity in conjunction with altered corticolimbic activation and CRF expression. GC-C agonism attenuated stress-induced colonic hypersensitivity and ERK phosphorylation, but had no effect on CRF expression, suggesting the analgesic effects of linaclotide occur independent of stress-driven CRF gene expression in corticolimbic circuitry.
Assuntos
Encéfalo/efeitos dos fármacos , Colo/efeitos dos fármacos , Hormônio Liberador da Corticotropina/genética , Agonistas da Guanilil Ciclase C/farmacologia , Nociceptividade/efeitos dos fármacos , Peptídeos/farmacologia , Receptores de Enterotoxina/metabolismo , Estresse Psicológico/metabolismo , Animais , Encéfalo/metabolismo , Núcleo Central da Amígdala/efeitos dos fármacos , Núcleo Central da Amígdala/metabolismo , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Colo/metabolismo , Hormônio Liberador da Corticotropina/efeitos dos fármacos , Hormônio Liberador da Corticotropina/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Sistema Límbico/efeitos dos fármacos , Sistema Límbico/metabolismo , Limiar da Dor , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/metabolismo , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Ratos , Estresse Psicológico/fisiopatologiaRESUMO
The basal ganglia (BG) are involved in cognitive/motivational functions in addition to movement control. Thus, BG segregated circuits, the sensorimotor (SM) and medial prefrontal (mPF) circuits, process different functional domains, such as motor and cognitive/motivational behaviours, respectively. With a high presence in the BG, the CB1 cannabinoid receptor modulates BG circuits. Furthermore, dopamine (DA), one of the principal neurotransmitters in the BG, also plays a key role in circuit functionality. Taking into account the interaction between DA and the endocannabinoid system at the BG level, we investigated the functioning of BG circuits and their modulation by the CB1 receptor under DA-depleted conditions. We performed single-unit extracellular recordings of substantia nigra pars reticulata (SNr) neurons with simultaneous cortical stimulation in sham and 6-hydroxydopamine (6-OHDA)-lesioned rats, together with immunohistochemical assays. We showed that DA loss alters cortico-nigral information processing in both circuits, with a predominant transmission through the hyperdirect pathway in the SM circuit and an increased transmission through the direct pathway in the mPF circuit. Moreover, although DA denervation does not change CB1 receptor density, it impairs its functionality, leading to a lack of modulation. These data highlight an abnormal transfer of information through the associative/limbic domains after DA denervation that may be related to the non-motor symptoms manifested by Parkinson's disease patients.
Assuntos
Gânglios da Base/metabolismo , Dopamina/metabolismo , Sistema Límbico/metabolismo , Córtex Motor/metabolismo , Neurônios/metabolismo , Parte Reticular da Substância Negra/metabolismo , Receptor CB1 de Canabinoide/metabolismo , Potenciais de Ação/fisiologia , Animais , Gânglios da Base/efeitos dos fármacos , Modelos Animais de Doenças , Eletrodos , Imuno-Histoquímica , Sistema Límbico/efeitos dos fármacos , Masculino , Córtex Motor/efeitos dos fármacos , Vias Neurais/efeitos dos fármacos , Vias Neurais/metabolismo , Neurônios/efeitos dos fármacos , Oxidopamina/toxicidade , Doença de Parkinson/metabolismo , Parte Reticular da Substância Negra/citologia , Parte Reticular da Substância Negra/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Ratos , Receptor CB1 de Canabinoide/fisiologia , Simpatectomia Química , Simpatolíticos/toxicidadeRESUMO
Aging is a complex process that can lead to neurodegeneration and, consequently, several pathologies, including dementia. Physiological aging leads to changes in several body organs, including those of the central nervous system (CNS). Morphological changes in the CNS and particularly the brain result in motor and cognitive deficits affecting learning and memory and the circadian cycle. Characterizing neural modifications is critical to designing new therapies to target aging and associated pathologies. In this review, we compared aging to the changes occurring within the brain and particularly the limbic system. Then, we focused on key natural compounds, apamin, cerebrolysin, Curcuma longa, resveratrol, and N-PEP-12, which have shown neurotrophic effects particularly in the limbic system. Finally, we drew our conclusions delineating future perspectives for the development of novel natural therapeutics to ameliorate aging-related processes.
Assuntos
Envelhecimento/efeitos dos fármacos , Sistema Límbico/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Nootrópicos/farmacologia , Envelhecimento/metabolismo , Aminoácidos/farmacologia , Animais , Apamina/farmacologia , Curcuma , Sistema Límbico/metabolismo , Plasticidade Neuronal/efeitos dos fármacos , Neurônios/metabolismo , Extratos Vegetais/farmacologia , Ratos , Resveratrol/farmacologiaRESUMO
Antidepressant fluoxetine (Flx) is the first therapeutic choice for the treatment of major depression (MD), however neuroanatomical spots of its action remain unclear. Immunohistochemical detection of c-Fos protein expression has been used for mapping activated neuronal circuits upon various stressors and drugs. We investigated the effect of 3 weeks of Flx treatment (15 mg/kg/day) on changes in neuronal activity, by mapping the number of c-Fos+ cells, in several brain subregions in adult male rats of control and following 3 weeks of chronic social isolation (CSIS), an animal model of depression. The aim was to identify brain subregions activated by vehicle or Flx treatment in both controls or simultaneously applied with CSIS. Flx prevented depressive- and anxiety-like behaviors in CSIS rats. In controls, Flx increased the number of c-Fos+ cells in the anterior/posterior piriform cortex (aPirCx, pPirCx), retrosplenial cortex dysgranular (RSD) and granular, c region (RSGc), dorsal hippocampal subregions (CA1d, CA2, CA3d, DGd), lateral habenula (LHB), paraventricular thalamic nucleus, posterior part (PVP) and lateral/basolateral complex of amygdala (LA/BL). CSIS-induced neuronal activation was observed in brain subregions implicated in mood and other mental disorders such as aPirCx, pPirCx, caudate putamen (CPu), acumbens nucleus shell (AcbSh), RSD, RSGc, DGd, PVP and LA/BL. Flx increased neuronal activation in both controls and CSIS rats in the CA1d, CA2, CA3d, PVP, LA/BL, while in striatum increased neuronal activation was observed only in CSIS. Our data identify activated CSIS-related brain subregions and/or Flx treatment, in which Flx increased c-Fos protein expression in CSIS rats.