1.
Aoun, E. G., et al.
(författare)
A relationship between the aldosterone-mineralocorticoid receptor pathway and alcohol drinking: preliminary translational findings across rats, monkeys and humans
2018
Ingår i: Molecular Psychiatry. - : NATURE PUBLISHING GROUP. - 1359-4184 .- 1476-5578. ; 23:6, s. 1466-1473
Tidskriftsartikel (refereegranskat) abstract
Aldosterone regulates electrolyte and fluid homeostasis through binding to the mineralocorticoid receptors (MRs). Previous work provides evidence for a role of aldosterone in alcohol use disorders (AUDs). We tested the hypothesis that high functional activity of the mineralocorticoid endocrine pathway contributes to vulnerability for AUDs. In Study 1, we investigated the relationship between plasma aldosterone levels, ethanol self-administration and the expression of CYP11B2 and MR (NR3C2) genes in the prefrontal cortex area (PFC) and central nucleus of the amygdala (CeA) in monkeys. Aldosterone significantly increased after 6- and 12-month ethanol self-administration. NR3C2 expression in the CeA was negatively correlated to average ethanol intake during the 12 months. In Study 2, we measured Nr3c2 mRNA levels in the PFC and CeA of dependent and nondependent rats and the correlates with ethanol drinking during acute withdrawal. Low Nr3c2 expression levels in the CeA were significantly associated with increased anxiety-like behavior and compulsive-like drinking in dependent rats. In Study 3, the relationship between plasma aldosterone levels, alcohol drinking and craving was investigated in alcohol-dependent patients. Non-abstinent patients had significantly higher aldosterone levels than abstinent patients. Aldosterone levels positively correlated with the number of drinks consumed, craving and anxiety scores. These findings support a relationship between ethanol drinking and the aldosterone/MR pathway in three different species.
2.
Augier, Eric, et al.
(författare)
The GABA(B) Positive Allosteric Modulator ADX71441 Attenuates Alcohol Self-Administration and Relapse to Alcohol Seeking in Rats
2017
Ingår i: Neuropsychopharmacology. - : NATURE PUBLISHING GROUP. - 0893-133X .- 1740-634X. ; 42:9, s. 1789-1799
Tidskriftsartikel (refereegranskat) abstract
GABAergic signaling is involved in modulating the reinforcing properties of alcohol, and GABA(B) receptors have been proposed as a potential target for clinical treatment of alcoholism. The orthosteric GABA(B) receptor agonist baclofen has been shown to suppress operant self-administration of alcohol in animals and alcohol use in alcohol-dependent patients, but its utility is limited by a narrow therapeutic index. We tested the effects of ADX71441, a novel GABA(B) receptor positive allosteric modulator, on alcohol-related behaviors in rats. We first assessed the effects of ADX71441 ( 1, 3, 10 and 30 mg/kg, I.P.) on both non-dependent and dependent male Wistar rats trained to self-administer 20% alcohol. We then determined the effects of ADX71441 on stress-induced as well as cue-induced relapse-like behavior. Finally, we sought to identify the brain regions through which ADX71441 may act to prevent relapse-like behavior by mapping the neuronal activation induced by stress-induced reinstatement of alcohol-seeking using c-Fos immunohistochemistry. ADX71441 dose-dependently decreased alcohol self-administration of both dependent and non-dependent animals, but its potency was higher in alcohol-dependent rats. Furthermore, both cue-and stress-induced alcohol seeking were blocked by the GABA(B) receptor positive allosteric modulator. Finally, pretreatment with 3 mg/kg of ADX71441 before stress-induced reinstatement significantly decreased c-Fos expression in a network of brain regions implicated in stress-induced relapse, comprising the nucleus accumbens shell, the dorsal raphe nucleus and the medial prefrontal cortex. Our findings support a causal role of GABAB receptors in alcohol reinforcement and relapse to alcohol seeking. These effects are observed in the absence of significant sedative side effects. Jointly, these observations indicate that GABAB receptor positive allosteric modulators merit being tested clinically for the treatment of alcoholism. Our data also point to a potential biomarker of target engagement for early clinical studies.
3.
Barbier, Estelle, et al.
(författare)
Dependence-induced increase of alcohol self-administration and compulsive drinking mediated by the histone methyltransferase PRDM2
2017
Ingår i: Molecular Psychiatry. - : NATURE PUBLISHING GROUP. - 1359-4184 .- 1476-5578. ; 22:12, s. 1746-1758
Tidskriftsartikel (refereegranskat) abstract
Epigenetic processes have been implicated in the pathophysiology of alcohol dependence, but the specific molecular mechanisms mediating dependence-induced neuroadaptations remain largely unknown. Here, we found that a history of alcohol dependence persistently decreased the expression of Prdm2, a histone methyltransferase that monomethylates histone 3 at the lysine 9 residue (H3K9me1), in the rat dorsomedial prefrontal cortex (dmPFC). Downregulation of Prdm2 was associated with decreased H3K9me1, supporting that changes in Prdm2 mRNA levels affected its activity. Chromatin immunoprecipitation followed by massively parallel DNA sequencing showed that genes involved in synaptic communication are epigenetically regulated by H3K9me1 in dependent rats. In non-dependent rats, viral-vector-mediated knockdown of Prdm2 in the dmPFC resulted in expression changes similar to those observed following a history of alcohol dependence. Prdm2 knockdown resulted in increased alcohol self-administration, increased aversion-resistant alcohol intake and enhanced stress-induced relapse to alcohol seeking, a phenocopy of postdependent rats. Collectively, these results identify a novel epigenetic mechanism that contributes to the development of alcohol-seeking behavior following a history of dependence.
4.
Barbier, Estelle, et al.
(författare)
Downregulation of Synaptotagmin 1 in the Prelimbic Cortex Drives Alcohol-Associated Behaviors in Rats
2021
Ingår i: Biological Psychiatry. - : Elsevier BV. - 0006-3223 .- 1873-2402. ; 89:4, s. 398-406
Tidskriftsartikel (refereegranskat) abstract
Background: Alcohol addiction is characterized by persistent neuroadaptations in brain structures involved in motivation, emotion, and decision making, including the medial prefrontal cortex, the nucleus accumbens, and the amygdala. We previously reported that induction of alcohol dependence was associated with long-term changes in the expression of genes involved in neurotransmitter release. Specifically, Syt1, which plays a key role in neurotransmitter release and neuronal functions, was downregulated. Here, we therefore examined the role of Syt1 in alcohol-associated behaviors in rats. Methods: We evaluated the effect of Syt1 downregulation using an adeno-associated virus (AAV) containing a short hairpin RNA against Syt1. Cre-dependent Syt1 was also used in combination with an rAAV2 retro-Cre virus to assess circuit-specific effects of Syt1 knockdown (KD). Results: Alcohol-induced downregulation of Syt1 is specific to the prelimbic cortex (PL), and KD of Syt1 in the PL resulted in escalated alcohol consumption, increased motivation to consume alcohol, and increased alcohol drinking despite negative consequences (“compulsivity”). Syt1 KD in the PL altered the excitation/inhibition balance in the basolateral amygdala, while the nucleus accumbens core was unaffected. Accordingly, a projection-specific Syt1 KD in the PL–basolateral amygdala projection was sufficient to increase compulsive alcohol drinking, while a KD of Syt1 restricted to PL–nucleus accumbens core projecting neurons had no effect on tested alcohol-related behaviors. Conclusions: Together, these data suggest that dysregulation of Syt1 is an important mechanism in long-term neuroadaptations observed after a history of alcohol dependence, and that Syt1 regulates alcohol-related behaviors in part by affecting a PL–basolateral amygdala brain circuit. © 2020 Society of Biological Psychiatry
5.
Barbier, Estelle, et al.
(författare)
mTORC and ProSAPiP1: How Alcohol Changes Synapses of Reward Circuitry
2017
Ingår i: Neuron. - : CELL PRESS. - 0896-6273 .- 1097-4199. ; 96:1
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt) abstract
Alcohol addiction is characterized by broad and persistent changes in brain function, but the underlying neural adaptations remain largely unknown. In this issue of Neuron, Laguesse et al. (2017) describe a neural mechanism through which long-term alcohol exposure induces structural and synaptic adaptations that promote excessive alcohol use.
6.
Barchiesi, Riccardo, 1989-, et al.
(författare)
An epigenetic mechanism for over-consolidation of fear memories
2022
Ingår i: Molecular Psychiatry. - : Springer Nature. - 1359-4184 .- 1476-5578. ; 27:12, s. 4893-4904
Tidskriftsartikel (refereegranskat) abstract
Excessive fear is a hallmark of anxiety disorders, a major cause of disease burden worldwide. Substantial evidence supports a role of prefrontal cortex-amygdala circuits in the regulation of fear and anxiety, but the molecular mechanisms that regulate their activity remain poorly understood. Here, we show that downregulation of the histone methyltransferase PRDM2 in the dorsomedial prefrontal cortex enhances fear expression by modulating fear memory consolidation. We further show that Prdm2 knock-down (KD) in neurons that project from the dorsomedial prefrontal cortex to the basolateral amygdala (dmPFC-BLA) promotes increased fear expression. Prdm2 KD in the dmPFC-BLA circuit also resulted in increased expression of genes involved in synaptogenesis, suggesting that Prdm2 KD modulates consolidation of conditioned fear by modifying synaptic strength at dmPFC-BLA projection targets. Consistent with an enhanced synaptic efficacy, we found that dmPFC Prdm2 KD increased glutamatergic release probability in the BLA and increased the activity of BLA neurons in response to fear-associated cues. Together, our findings provide a new molecular mechanism for excessive fear responses, wherein PRDM2 modulates the dmPFC -BLA circuit through specific transcriptomic changes.
7.
Bernardi, R. E., et al.
(författare)
A gene-by-sex interaction for nicotine reward: evidence from humanized mice and epidemiology
2016
Ingår i: Translational Psychiatry. - : NATURE PUBLISHING GROUP. - 2158-3188. ; 6:e861
Tidskriftsartikel (refereegranskat) abstract
It has been proposed that vulnerability to nicotine addiction is moderated by variation at the mu-opioid receptor locus (OPRM1), but results from human studies vary and prospective studies based on genotype are lacking. We have developed a humanized mouse model of the most common functional OPRM1 polymorphism rs1799971_A4G (A118G). Here we use this model system together with a cohort of German youth to examine the role of the OPRM1 A118G variation on nicotine reward. Nicotine reinforcement was examined in the humanized mouse model using i.v. self-administration. Male (n = 17) and female (n = 26) mice homozygous either for the major human A allele (AA) or the minor G allele (GG) underwent eight daily 2 h sessions of nicotine self-administration. Furthermore, male (n = 104) and female (n = 118) subjects homozygous for the A allele or carrying the G allele from the Mannheim Study of Children at Risk were evaluated for pleasurable and unpleasant experiences during their initial smoking experience. A significant sex-by-genotype effect was observed for nicotine self-administration. Male 118GG mice demonstrated higher nicotine intake than male 118AA mice, suggesting increased nicotine reinforcement. In contrast, there was no genotype effect in female mice. Human male G allele carriers reported increased pleasurable effects from their first smoking experience, as compared to male homozygous A, female G and female homozygous A allele carriers. The 118G allele appears to confer greater sensitivity to nicotine reinforcement in males, but not females.
8.
Björk, Karl, et al.
(författare)
Ethanol-induced activation of AKT and DARPP-32 in the mouse striatum mediated by opioid receptors
2010
Ingår i: Addiction Biology. - : Wiley-Blackwell. - 1355-6215 .- 1369-1600. ; 15:3, s. 299-303
Tidskriftsartikel (refereegranskat) abstract
The reinforcing properties of ethanol are in part attributed to interactions between opioid and dopaminergic signaling pathways, but intracellular mediators of such interactions are poorly understood. Here we report that an acute ethanol challenge induces a robust phosphorylation of two key signal transduction kinases, AKT and DARPP-32, in the striatum of mice. Ethanol-induced AKT phosphorylation was blocked by the opioid receptor antagonist naltrexone but unaffected by blockade of dopamine D2 receptors via sulpiride. In contrast, DARPP-32 phosphorylation was abolished by both antagonists. These data suggest that ethanol acts via two distinct but potentially synergistic striatal signaling cascades. One of these is D2-dependent, while the other is not. These findings illustrate that pharmacology of ethanol reward is likely more complex than that for other addictive drugs.
9.
Björk, Karl, et al.
(författare)
β-Arrestin 2 knockout mice exhibit sensitized dopamine release and increased reward in response to a low dose of alcohol
2013
Ingår i: Psychopharmacology. - : Springer. - 0033-3158 .- 1432-2072. ; 230:3, s. 439-449
Tidskriftsartikel (refereegranskat) abstract
RationaleThe rewarding effects of alcohol have been attributed to interactions between opioid and dopaminergic system within the mesolimbic reward pathway. We have previously shown that ablation of β-arrestin 2 (Arrb2), a crucial regulator of μ-opioid receptor function, attenuates alcohol-induced hyperlocomotion and c-fos activation in the nucleus accumbens.ObjectivesHere, we further investigated the role of Arrb2 in modulating alcohol-induced dopamine (DA) release and conditioned place preference (CPP). We also assessed the functional importance of Arrb2 for μ-opioid receptor surface expression and signaling following an acute alcohol challenge.MethodsAlcohol-evoked (0.375, 0.75, and 1.5 g/kg intraperitoneally) DA release was measured by in vivo microdialysis in the shell of nucleus accumbens. Reward was assessed by the CPP paradigm. Receptor function was assessed by μ-receptor binding and [35S]GTP-γ-S autoradiography.ResultsIn Arrb2 knockout mice accumbal DA levels reach maximum response at a lower dose compared to wild-type (wt) animals. In line with these results, Arrb2 knockout mice display increased CPP for alcohol as compared to wt mice. Finally, Arrb2 mutant mice display increased μ-opioid receptor signaling in the ventral and dorsal striatum and amygdala in response to a low dose of alcohol, indicating impaired desensitization mechanisms in these mice.ConclusionsOur results show that Arrb2 modulates the response to low doses of alcohol on various levels including μ-opioid receptor signaling, DA release, and reward. They also reveal a clear dissociation between the effects of Arrb2 on psychomotor and reward behaviors.
10.
Böhme, Rebecca, et al.
(författare)
Distinction of self-produced touch and social touch at cortical and spinal cord levels
2019
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 116:6, s. 2290-2299
Tidskriftsartikel (refereegranskat) abstract
Differentiation between self-produced tactile stimuli and touch by others is necessary for social interactions and for a coherent concept of "self." The mechanisms underlying this distinction are unknown. Here, we investigated the distinction between self-and other-produced light touch in healthy volunteers using three different approaches: fMRI, behavioral testing, and somatosensory-evoked potentials (SEPs) at spinal and cortical levels. Using fMRI, we found self-other differentiation in somatosensory and sociocognitive areas. Other-touch was related to activation in several areas, including somatosensory cortex, insula, superior temporal gyrus, supramarginal gyrus, striatum, amygdala, cerebellum, and prefrontal cortex. During self-touch, we instead found deactivation in insula, anterior cingulate cortex, superior temporal gyrus, amygdala, parahippocampal gyrus, and prefrontal areas. Deactivation extended into brain areas encoding low-level sensory representations, including thalamus and brainstem. These findings were replicated in a second cohort. During self-touch, the sensorimotor cortex was functionally connected to the insula, and the threshold for detection of an additional tactile stimulus was elevated. Differential encoding of self-vs. other-touch during fMRI correlated with the individual self-concept strength. In SEP, cortical amplitudes were reduced during self-touch, while latencies at cortical and spinal levels were faster for other-touch. We thus demonstrated a robust self-other distinction in brain areas related to somatosensory, social cognitive, and interoceptive processing. Signs of this distinction were evident at the spinal cord. Our results provide a framework for future studies in autism, schizophrenia, and emotionally unstable personality disorder, conditions where symptoms include social touch avoidance and poor self-vs.-other discrimination.
