| 1. |
- Novak, Martin, et al.
(författare)
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Incentive Learning Underlying Cocaine-Seeking Requires mGluR5 Receptors Located on Dopamine D1 Receptor-Expressing Neurons
- 2010
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Ingår i: JOURNAL OF NEUROSCIENCE. - : Society for Neuroscience. - 0270-6474. ; 30:36, s. 11973-11982
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the psychobiological basis of relapse remains a challenge in developing therapies for drug addiction. Relapse in cocaine addiction often occurs following exposure to environmental stimuli previously associated with drug taking. The metabotropic glutamate receptor, mGluR5, is potentially important in this respect; it plays a central role in several forms of striatal synaptic plasticity proposed to underpin associative learning and memory processes that enable drug-paired stimuli to acquire incentive motivational properties and trigger relapse. Using cell type-specific RNA interference, we have generated a novel mouse line with a selective knock-down of mGluR5 in dopamine D1 receptor-expressing neurons. Although mutant mice self-administer cocaine, we show that reinstatement of cocaine-seeking induced by a cocaine-paired stimulus is impaired. By examining different aspects of associative learning in the mutant mice, we identify deficits in specific incentive learning processes that enable a reward-paired stimulus to directly reinforce behavior and to become attractive, thus eliciting approach toward it. Our findings show that glutamate signaling through mGluR5 located on dopamine D1 receptor-expressing neurons is necessary for incentive learning processes that contribute to cue-induced reinstatement of cocaine-seeking and which may underpin relapse in drug addiction.
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| 2. |
- Alkhori, Liza
(författare)
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Mechanisms of sensory neuron diversification during development and in the adult Drosophila : How to make a difference
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The nervous system contains a vast number of neurons and displays a great diversity in cell types and classes. Even though this has been known for a long time, the exact mechanism of cell specification is still poorly understood. How does a cell know what type of neuron to which it should be specified? It is important to understand cellular specification, not only for our general understanding of biological processes, but also to allow us to develop treatments for patients with destructive diseases, such as Alzheimer’s, Parkinson, cancer or stroke. To address how neuronal specification and thereby diversification is evolved, we have chosen to study a complex but defined set of neurons, the Drosophila olfactory system. Olfactory sensory neurons (OSNs) detect an enormous variety of small volatile molecules with extremely high specificity and sensitivity. The adult Drosophila olfactory system contains 34 OSN classes each defined by their expression of a specific odorant receptor (OR). In both insects and vertebrates, each OSN expresses only one OR. In mouse there are approximately 1200 and in Drosophila 60 different OR genes. Despite the range of mechanisms known to determine cell identity and that the olfactory system is remarkably conserved across the phyla, it is still unclear how an OSN chooses to express a particular OR from a large genomic repertoire. In this thesis, the specification and diversification of the final steps establishing an OSN identity is addressed. We find seven transcription factors that are continuously required in different combinations for the expression of all ORs. The TFs can in different gene context both activate and repress OR expression, making the regulation more economical and indicating that repression is crucial for correct gene expression. We further identified a repressor complex that is able to segregate OR expression between OSN classes and propose a mechanism on how one single co-repressor can specify a large number of neuron classes.Exploring the OSN we found the developmental Hh signalling pathway is expressed in the postmitotic neuron. We show several fundamental similarities between the canonical Drosophila Hh pathway and the cilia mediated Hh transduction in component function. Further investigation revealed a function of cilia mediated Hh signalling in sensory neuron modulator. The results generated here will create a greater in vivo understanding of how postmitotic processes generate neurons with different fates and contribute to the maintaining of neuron function.
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| 3. |
- Aziz, Abdul Maruf Asif
(författare)
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Neuropeptide Receptors as Treatment Targets in Alcohol Use Disorders
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Alcohol use disorder (AUD) is a complex disorder with multiple pathophysiological processes contributing to the initiation, progression and development of the disease state. AUD is a chronic relapsing disease with escalation of alcohol-intake over time in repeated cycles of tolerance, abstinence and relapse and hence, it is very difficult to treat. There are only a few currently available treatments with narrow efficacy and variable patient response. Thus it is important to find new, more effective medications to increase the number of patients who can benefit from pharmacological treatment of AUD.The research presented in this thesis work focuses on the critical involvement of central neuropeptides in alcohol-related behaviors. The overall aim was to evaluate the nociceptin/orphanin FQ (NOP) receptor, the neuropeptide Y (NPY) Y2 receptor and the melanin-concentrating hormone (MCH) receptor 1 as novel and potential pharmacological treatment targets for AUD by testing the NOP receptor agonist SR-8993, the NPY-Y2 receptor antagonist CYM-9840 and the MCH1 receptor antagonist GW803430 in established animal models.In the first study (Paper I), the novel and selective NOP agonist SR-8993 was assessed in rat models of motivation to obtain alcohol and relapse to alcohol seeking behavior using the operant self-administration (SA) paradigm. Firstly, treatment with SR-8993 (1 mg/kg) showed a mildly anxiolytic effect and reversed acute alcohol withdrawal-induced “hangover” anxiety in the elevated plus-maze (EPM). Next, it potently attenuated alcohol SA and motivation to obtain alcohol in the progressive ratio responding (PRR) and reduced both alcohol cue-induced and yohimbine stress-induced reinstatement of alcohol seeking, without affecting the pharmacology and metabolism of alcohol nor other control behaviors. To extend these findings, SR-8993 was evaluated in escalated alcohol-intake in rats. Treatment with SR-8993 significantly suppressed alcohol-intake and preference in rats that were trained to consume high amounts of alcohol in the two-bottle free choice intermittent access (IA) paradigm. SR-8993 also blocked operant SA of alcohol in rats that showed robust escalation in operant alcohol SA following chronic IA exposure to alcohol.In the second study (Paper II), SR-8993 was further evaluated in a model for escalated alcohol-intake induced by long-term IA exposure to alcohol. The effect of previous experience on operant alcohol SA on two-bottle free choice preference drinking was evaluated and sensitivity to treatment with SR-8993 was tested in rats selected for escalated and non-escalated alcohol seeking behavior. We found that rats exposed to the combined SA-IA paradigm showed greater sensitivity to SR-8993 treatment. In addition, acute escalation of alcohol SA after a three-week period of abstinence was completely abolished by pretreatment with SR-8993.In the third study (Paper III), the effects of the novel, small molecule NPY-Y2 antagonist CYM-9840 were tested in operant alcohol SA, PRR which is a model for motivation to work for alcohol and reinstatement of alcohol-seeking behavior. Treatment with CYM-9840 (10 mg/kg) potently attenuated alcohol SA, progressive ratio responding and stress-induced reinstatement using yohimbine as the stressor, while alcohol cue-induced reinstatement was unaffected. Moreover, a range of control behaviors including taste sensitivity, locomotor and pharmacological sensitivity to the sedative effects of alcohol remained unaffected by CYM-9840 pretreatment, indicating that its effects are specific to the rewarding and motivational aspects of alcohol-intake and related behaviors. CYM-9840 also reversed acute alcohol withdrawal-induced “hangover” anxiety measured in the EPM and reduced alcohol-intake in the 4 hour limited access two-bottle free choice preference drinking model.Finally, in the fourth study (Paper IV), the selective MCH1-R antagonist GW803430 was tested in rat models of escalated alcohol-intake. Pretreatment with GW803430 (effective at 10 & 30 mg/kg) dose-dependently reduced alcohol and food-intake in rats that consumed high amounts of alcohol during IA, while it only decreased food-intake in rats that consumed low amounts of alcohol during IA, likely due to a floor effect. Upon protracted abstinence following IA, GW803430 significantly reduced operant alcohol SA and this was associated with adaptations in MCH and MCH1-R gene-expression. In contrast, GW803430 did not affect escalated alcohol SA induced by chronic alcohol vapor exposure and this was accompanied by no change in MCH or MCH1-R gene expression. Overall, these results suggest that the MCH1-R antagonist affects alcohol-intake through regulation of both motivation for caloric-intake and the rewarding properties of alcohol.In conclusion, our results suggest critical roles for these central neuropeptides in the regulation of anxiety and of alcohol reward, making them potential pharmacological targets in the treatment of AUD.
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| 4. |
- Bagheri, Maryam
(författare)
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Neuroprotective Effect of Genistein : Studies in Rat Models of Parkinson’s and Alzheimer’s Disease
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Parkinson’s disease (PD) and Alzheimer’s disease (AD) are neurodegenerative disorders that mainly affect the elderly population. It is believed that oxidative stress is involved in development of both these diseases and that estrogen deficiency is a risk factor for development of AD. Genistein is a plant-derived compound that is similar in structure to estrogen and has anti-oxidative properties. The general objective of the present research was to evaluate the effects of genistein on neurodegeneration in rat models of PD and AD.Using a rat model of PD, we found that a single intraperitoneal dose of genistein 1 h before intrastriatal injection of 6-hydroxydopamine (6-OHDA) attenuated apomorphine-induced rotational behavior and protected the neurons of substantia nigra pars compacta against 6-OHDA toxicity.To produce an animal model of AD, we injected Aβ1–40 into the hippocampus of rats. Using groups of these Aβ1–40-lesioned animals, the involvement of estrogen receptors (ERs) was evaluated by intracerebroventricular injection of the estrogen receptor antagonist fulvestrant, and the role of oxidative stress was studied by measuring levels of malondialdehyde (MDA), nitrite, and superoxide dismutase (SOD) activity. The results showed that intrahippocampal injection of Aβ1–40 caused the following: lower spontaneous alternation score in Y-maze tasks, impaired retention and recall capability in the passive avoidance test, and fewer correct choices and more errors in a radial arm maze (RAM task), elevated levels of MDA and nitrite, and a signiHcant reduction in SOD activity in the brain tissue. Furthermore, hippocampus in theses rats exhibited Aβ1–40 immunoreactive aggregates close to the lateral blade of the dentate gyrus (DGlb), extensive neuronal degeneration in the DGlb, high intracellular iNOS+ and nNOS+ immunoreactivity, and extensive astrogliosis.Genistein pretreatment ameliorated the Aβ-induced impairment of short-term spatial memory, and this effect occurred via an estrogenic pathway and through attenuation of oxidative stress. Genistein also ameliorated the degeneration of neurons, inhibited the formation of Aβ1–40-positive aggregates, and alleviated Aβ1–40-induced astrogliosis in the hippocampus.
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| 5. |
- Bergström, Anna, et al.
(författare)
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Acetaminophen Attenuates Pulmonary Vascular Resistance and Pulmonary Arterial Pressure and Inhibits Cardiovascular Collapse in a Porcine Model of Endotoxemia
- 2023
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Ingår i: Shock. - : Shock Society. - 1073-2322 .- 1540-0514. ; 59:3, s. 442-448
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Tidskriftsartikel (refereegranskat)abstract
- Acetaminophen (paracetamol) is often used in critically ill patients with fever and pain; however, little is known about the effects of acetaminophen on cardiovascular function during systemic inflammation. Here, we investigated the effect of acetaminophen on changes in the systemic and pulmonary circulation induced by endotoxin (0.5 μg/kg/h) in anesthetized pigs. Endotoxin infusion led to a rapid increase in pulmonary artery (PA)-pressure and pulmonary vascular resistance index (PVRI). Acetaminophen delayed and attenuated this increase. Furthermore, acetaminophen reduced tachycardia and decreased stroke volume, accompanied by systemic inflammation, without affecting inflammatory parameters such as white blood cell count and TNF-α in blood. As a proof of concept, we injected a high dose of endotoxin (100 μg), which induced rapid cardiovascular collapse in pigs. Pigs treated with acetaminophen survived with no obvious hemodynamic instability during the 50 min observation period. In conclusion, acetaminophen attenuates the effects of endotoxin on pulmonary circulation in anesthetized pigs. This may play a role in severe systemic inflammation.
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| 6. |
- Bilbao, Ainhoa, et al.
(författare)
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Loss of the Ca2+/calmodulin-dependent protein kinase type IV in dopaminoceptive neurons enhances behavioral effects of cocaine
- 2008
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences; 1999. - 0027-8424 .- 1091-6490. ; 105:45, s. 17549-17554
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Tidskriftsartikel (refereegranskat)abstract
- The persistent nature of addiction has been associated with activity-induced plasticity of neurons within the striatum and nucleus accumbens (NAc). To identify the molecular processes leading to these adaptations, we performed Cre/loxP-mediated genetic ablations of two key regulators of gene expression in response to activity, the Ca2+/calmodulin-dependent protein kinase IV (CaMKIV) and its postulated main target, the cAMP-responsive element binding protein (CREB). We found that acute cocaine-induced gene expression in the striatum was largely unaffected by the loss of CaMKIV. On the behavioral level, mice lacking CaMKIV in dopaminoceptive neurons displayed increased sensitivity to cocaine as evidenced by augmented expression of locomotor sensitization and enhanced conditioned place preference and reinstatement after extinction. However, the loss of CREB in the forebrain had no effect on either of these behaviors, even though it robustly blunted acute cocaine-induced transcription. To test the relevance of these observations for addiction in humans, we performed an association study of CAMK4 and CREB promoter polymorphisms with cocaine addiction in a large sample of addicts. We found that a single nucleotide polymorphism in the CAMK4 promoter was significantly associated with cocaine addiction, whereas variations in the CREB promoter regions did not correlate with drug abuse. These findings reveal a critical role for CaMKIV in the development and persistence of cocaine-induced behaviors, through mechanisms dissociated from acute effects on gene expression and CREB-dependent transcription.
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| 7. |
- Björk Wilhelms, Daniel, et al.
(författare)
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Cyclooxygenase isoform exchange blocks inflammatory symptoms
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Cyclooxygenase‐2 (COX‐2) is the main source of inducible prostaglandin E2 production and mediates inflammatory symptoms including fever, loss of appetite and hyperalgesia. In contrast, COX‐1 is dispensable for most inflammatory symptoms. Global deletion of COX‐2 leads to a blockade of inflammation‐induced fever and appetite loss but also to high rates of fetal mortality. The latter is unfortunate since mice without COX‐2 are powerful tools in the study of inflammation and cardiovascular medicine. The differential functionality of the COX isoforms could be due to differences in regulatory regions of the genes, leading to different expression patterns, or to differences in the coding sequence, leading to distinct functional properties of the proteins. To study this in the context of inflammatory symptoms, we used mice in which the coding sequence of COX‐2 was replaced by the corresponding sequence of COX‐1. In these mice, COX‐1 mRNA was induced by inflammation but COX‐1 protein expression did not fully mimic inflammation‐induced COX‐2 expression. Just like mice globally lacking COX‐2, these mice showed a complete lack of fever and inflammation‐induced anorexia. However, as previously reported, they displayed close to normal survival rates. This shows that the COX activity generated from the hybrid gene was strong enough to allow survival but not strong enough to mediate inflammatory symptoms, making the line an interesting alternative to COX‐2 knockouts for the study of inflammation. Our results also show that the functional differences between COX‐1 and COX‐2 in the context of inflammatory symptoms is not only dependent on the features of the promoter regions. Instead they indicate that there are fundamental differences between the isoforms at translational or posttranslational levels, which make hybrid genes less functional.
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| 8. |
- Björk Wilhelms, Daniel
(författare)
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Fever : Role of brain endothelial prostaglandins
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fever and loss of appetite are two of the most fundamental manifestations of disease. These disease symptoms, which lead to deviations from normal body temperature and food intake patterns, are seen in a vast array of infectious and inflammatory conditions. It is known that peripheral signals from the immune system are essential triggers for these responses, which are orchestrated by neuronal circuits in the brain. Due to the blood‐brain barrier, peripheral inflammatory signals require a specific mode of transmission into the brain. Such mechanisms have been proposed, but interventional studies of these mechanisms have never rendered conclusive results. In this thesis, we present the first functional evidence of cyclooxygenase 2 (COX‐2) and microsomal prostaglandin E synthase type 1 (mPGES‐1) mediated prostaglandin E2 synthesis in the blood‐brain barrier endothelial cells as a signaling mechanism in the initiation of inflammatory fever. We also show that one of the world’s most widely used antipyretics, paracetamol, acts by inhibition of COX‐2. Combined with the finding that COX‐2 and mPGES‐1 in brain endothelial cells play a key role in inflammatory fever, this finding suggests that paracetamol inhibits fever by specifically blocking prostaglandin E2 synthesis in blood‐brain barrier endothelium. In another symptom of inflammation, anorexia, the cellular origin of peripheral signals triggering acute anorexia are largely unknown. We show that the expression of myeloid differentiation primary response gene 88 (Myd88) in myeloid cells is important for the initiation of acute inflammatory anorexia and the maintenance of cancer anorexia‐cachexia.Taken together, these findings provide a significant advancement of our understanding of the mechanisms triggering acute inflammatory fever and anorexia and also explain the antipyretic effect of paracetamol.
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| 9. |
- Blomqvist, Anders, 1949-, et al.
(författare)
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Neural Mechanisms of Inflammation-Induced Fever
- 2018
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Ingår i: The Neuroscientist. - : Sage Publications. - 1073-8584 .- 1089-4098. ; 24:4, s. 381-399
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Forskningsöversikt (refereegranskat)abstract
- Fever is a common symptom of infectious and inflammatory disease. It is well-established that prostaglandin E-2 is the final mediator of fever, which by binding to its EP3 receptor subtype in the preoptic hypothalamus initiates thermogenesis. Here, we review the different hypotheses on how the presence of peripherally released pyrogenic substances can be signaled to the brain to elicit fever. We conclude that there is unequivocal evidence for a humoral signaling pathway by which proinflammatory cytokines, through their binding to receptors on brain endothelial cells, evoke fever by eliciting prostaglandin E-2 synthesis in these cells. The evidence for a role for other signaling routes for fever, such as signaling via circumventricular organs and peripheral nerves, as well as transfer into the brain of peripherally synthesized prostaglandin E-2 are yet far from conclusive. We also review the efferent limb of the pyrogenic pathways. We conclude that it is well established that prostaglandin E-2 binding in the preoptic hypothalamus produces fever by disinhibition of presympathetic neurons in the brain stem, but there is yet little understanding of the mechanisms by which factors such as nutritional status and ambient temperature shape the response to the peripheral immune challenge.
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| 10. |
- Boettcher, Mareike, et al.
(författare)
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NF-kappa B signaling in tanycytes mediates inflammation-induced anorexia
- 2020
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Ingår i: Molecular Metabolism. - : ELSEVIER. - 2212-8778. ; 39
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Infections, cancer, and systemic inflammation elicit anorexia. Despite the medical significance of this phenomenon, the question of how peripheral inflammatory mediators affect the central regulation of food intake is incompletely understood. Therefore, we have investigated the sickness behavior induced by the prototypical inflammatory mediator IL-1 beta. Methods: IL-1 beta was injected intravenously. To interfere with IL-1 beta signaling, we deleted the essential modulator of NF-kappa B signaling (Nemo) in astrocytes and tanycytes. Results: Systemic IL-1 beta increased the activity of the transcription factor NF-kB in tanycytes of the mediobasal hypothalamus (MBH). By activating NF-kappa B signaling, IL-1 beta induced the expression of cyclooxygenase-2 (Cox-2) and stimulated the release of the anorexigenic prostaglandin E-2 (PGE(2)) from tanycytes. When we deleted Nemo in astrocytes and tanycytes, the IL-1 beta-induced anorexia was alleviated whereas the fever response and lethargy response were unchanged. Similar results were obtained after the selective deletion of Nemo exclusively in tanycytes. Conclusions: Tanycytes form the brain barrier that mediates the anorexic effect of systemic inflammation in the hypothalamus. (C) 2020 The Author(s). Published by Elsevier GmbH. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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