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Interação funcional entre o sistema colinérgico e adrenérgico na manutenção da massa muscular e da placa motora / Functional interaction between Cholinergic and Adrenergic systems in the maintenance of muscle mass and motor endplateDanilo Lustrino Borges 28 August 2015 (has links)
Estudos anteriores de nosso laboratório demonstraram que a estimulação aguda dos receptores 2-adrenérgicos (2-AR) atenua a perda de massa muscular induzida pela desnervação motora (DEN) por meio de uma via dependente de AMPc/PKA. No entanto os mecanismos moleculares envolvidos na ativação crônica destes receptores ainda são pouco conhecidos. Por outro lado, a ativação desta via de sinalização também está envolvida no controle da estabilidade dos receptores nicotínicos (AChR) na junção neuromuscular (JNM), sugerindo que a densidade dos AChR possa estar sob controle neuro-humoral. Desta forma, aventou-se a possibilidade de que além dos efeitos protetores na massa muscular, a ativação dos receptores 2-AR pudesse mediar a estabilização dos AChR na placa motora. Para testar essa hipótese, camundongos foram submetidos à DEN através da secção do nervo ciático, um protocolo clássico de indução de atrofia muscular e desestabilização dos AChR, e tratados com salina ou clembuterol (CB), um 2-agonista seletivo, por até 14 dias. Após 3 dias de DEN, observou-se redução da massa muscular e aumento do conteúdo proteico e expressão do RNAm de genes relacionados à ativação do sistema Ubiquitina-Proteassoma (atrogina-1 e MuRF1) e do sistema autofágico/lisossomal (catepsina L e LC3). A DEN também promoveu aumento no turnover dos AChR, no número de vesículas endocíticas e na expressão do RNAm para a subunidade 1 dos AChR. Após 7 dias, a DEN reduziu a expressão dos genes relacionados à atrofia e aumentou a atividade da via do AMPc/PKA independentemente do tratamento com CB. Na tentativa de elucidar os sinais extracelulares que produziam esta resposta adaptativa, foi demonstrado que neurônios catecolaminérgicos trafegam ao longo do nervo ciático e sua ablação pela DEN reduziu o conteúdo de noradrenalina muscular. Baseados nestes resultados, foi postulado a existência de uma hipersenbilidade às catecolaminas em músculos desnervados cronicamente. O tratamento com CB por 3 dias aboliu o aumento da expressão dos atrogenes induzido pela DEN e este efeito foi associado ao maior conteúdo de AMPc e de substratos fosforilados pela PKA. Além disso, o CB diminuiu a hiperexpressão do RNAm para catepsina L e LC3 induzida pela DEN de 7 dias. Embora o CB não tenha alterado a meia-vida dos AChR em músculos inervados e desnervados, houve um total bloqueio do aumento do número de vesículas endocíticas contendo o AChR em músculos desnervados e tratados com CB. Corroborando estes dados, o CB aumentou a incorporação de AChR novos nas JNM e este efeito foi também associado à maior expressão do RNAm para a subunidade 1-AChR em músculos desnervados. Esta ação do CB no turnover dos AChR parece ser direta uma vez que neuroniôs catecolaminérgicos presentes no nervo ciático ativam receptores 2-ARe a produção de AMPc especificamente na JNM. Em estudos in vitro, foi demonstrado que a estimulação colinérgica produzida pelo carbacol (10-4M) diminuiu a velocidade de síntese de proteínas, aumentou a proteólise total e a atividade do sistema proteolítico Ca2+-dependente em músculos soleus de ratos por meio da ativação dos receptores nicotínicos. Este efeito catabólico do carbacol foi completamente bloqueado pela adição de CB (10-4M) ao meio de incubação. Os dados obtidos no presente estudo permitem sugerir que a estimulação crônica dos 2-AR no músculo esquelético induz um efeito anti-catabólico pela supressão dos sistemas proteolíticos proteassomal e lisossomal, provavelmente através da via de sinalização do AMPc/PKA. A inibição destes sistemas pode estar relacionada ao aumento do turnover dos AChR, uma vez que a velocidade de incorporação destes receptores na JNM foi aumentada pelo CB. Além disso, os achados que mostram a associação entre neurônios noradrenérgicos e colinérgicos no nervo ciático, que conjuntamente inervam as JNM, e a co-localização de receptores 2-AR e AChR na sinapse permitem sugerir a existência de uma interação funcional entre o sistema colinérgico e adrenérgico na manutenção da massa muscular e da placa motora. / Previous studies from our laboratory have shown that the acute stimulation of 2-adrenergic receptor (2-AR) attenuates the muscle loss induced by motor denervation (DEN) through a cAMP/PKA dependent pathway. However, the molecular mechanisms involved in the chronic activation of these receptors are poorly understood. Furthermore, the activation of this signaling pathway is also involved in controlling the stability of nicotinic receptors (AChR) at the neuromuscular junction (NMJ), suggesting that the density of AChR may be under neurohumoral control. Thus, we postulated that besides the protective effects on muscle mass the activation of 2-AR receptors could mediate the stabilization of AChR in the motor plate. To test this hypothesis, mice were submitted to DEN through of the sciatic nerve section, a classical protocol of induction muscle atrophy and destabilization of AChR, and were treated with saline or clenbuterol (CB), a selective 2-agonist for 14 days. DEN decreased the muscle mass and increased the protein content and mRNA expression of genes related to the activation of the ubiquitin-proteasome system (atrogin-1 and MuRF1) and autophagic/lysosomal system (cathepsin L and LC3). DEN also promoted an increase in the turnover of AChR, number of endocytic vesicles and the expression of mRNA for the 1 subunit of AChR. Interestingly, chronic DEN induced down-regulation of atrophy related-genes, and increased the activity of cAMP/PKA pathway independently of CB treatment. In an attempt to elucidate the extracellular signals that produced this adaptive response, it was demonstrated that catecholaminergic neurons travels along the sciatic nerve and its ablation by DEN reduces muscle norepinephrine content. Based on these results, it was postulated the existence of a muscle adrenergic hypersensitivity to circulating catecholamines induced by chronic DEN. CB treatment for 3 days completely abolished the higher expression of atrogenes and this effect was associated with increased Camp content and PKA phosphorylated substrates. Furthermore, CB decreased the DEN-induced hyperexpression of cathepsin L and LC3 mRNA at 7 days. Although CB has not altered the half-life of AChR in innervated and denervated muscles, it produced a total blockage of the increased number of endocytic vesicles containing the AChR in denervated muscles. Consistently, CB increased the incorporation of new AChR and this effect was associated with an increased expression of the 1-subunit AChR mRNA in denervated muscles. This action of CB on AChR turnover appears to be direct, since catecholaminergic neurons are present in the sciatic nerve stimulating 2-AR and cAMP production specifically in the NMJ. Furthermore, in vitro studies demonstrated that cholinergic stimulation produced by carbachol (10-4M) decreased the rate of protein synthesis and increased the proteolytic activity of Ca2+-dependent system in rat soleus muscle through activation of nicotinic receptors. This catabolic effect of carbachol was completely blocked by the addition of CB (10-4M) to the incubation medium. These data suggest that chronic stimulation of 2-AR in skeletal muscle induces an anti-catabolic effect by suppressing proteasomal and lysosomal proteolytic systems, probably through the cAMP/PKA signaling. The inhibition of these systems seems to be related to the increased AChR incorporation into NMJ induced by CB treatment. Moreover, the association between noradrenergic and cholinergic neurons in the sciatic nerve, both of which innervate the motor endplates, and the co-localization of AChR and 2-ARat the synapse suggest the existence of a functional interaction between cholinergic and adrenergic systems in the maintenance of muscle mass and motor endplate.
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Conception et synthèse de nouveaux agonistes de récepteurs métabotropiques du glutamate / Design and synthesis of metabotropic glutamate receptors agonistsCommare, Bruno 28 November 2014 (has links)
Le glutamate est le principal neurotransmetteur excitateur du système nerveux central. Il est responsable de la majorité des transmissions synaptiques. En revanche, cet acide aminé naturel est aussi impliqué dans de nombreuses neuropathologies notamment en cas de surconcentration au niveau des synapses. Les récepteurs métabotropiques du glutamate, capables de moduler la transmission synaptique, constituent des cibles thérapeutiques prometteuses. Ces récepteurs sont divisés en trois groupes et notre laboratoire s’est focalisé sur ceux du groupe III et particulièrement le sous-type 4 qui présente des caractéristiques intéressantes dans le traitement symptomatique de la douleur et de la maladie de Parkinson. Le manque d’outils pharmacologiques de ce récepteur nous a poussé à synthétiser de nouveaux agonistes orthostériques à partir du composé référence, le LSP4-2022. Cette molécule est issue de nombreuses optimisations chimiques du (S)-PCEP provenant lui d’un screening virtuel. Durant ces trois années de doctorat, nous avons pu peaufiner la relation structure-activité autour du LSP4-2022 en synthétisant des nouveaux analogues fluorés et hétérocycliques. En parallèle, une seconde étude nous a permis d’attribuer la configuration des deux diastéréomères constituants tous les composés testés à ce jour / Glutamate is the major excitatory neurotransmitter in the central nervous system. It is responsible of the majority of synaptic transmissions. In contrast, this natural amino acid is also involved in numerous neuropathologies and particularly in case of glutamate overconcentration in the synapse. Metabotropic glutamate receptors, that can modulate synaptic transmission, thus constitute promising therapeutic targets. These receptors are divided in three groups and our laboratory has been focused in group III and especially subtypes 4 which own interested properties in symptomatic treatment of pain and Parkinson Disease. The lack of pharmacological tools targeting this receptor prompts us to synthesize novel orthosteric agonist from the hit compound LSP4-2022. This molecule was obtained after several chemical optimizations from (S)-PCEP discovered from virtual screening. During my Ph.D., we could refine the structure-activity relationship of LSP4-2022 synthesizing new fluorinated and heterocyclic derivatives. Besides, a second study was carried out to identify the configuration of the two diastereomers which form tested compounds
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Trends and Patterns in Use of Medications for Opioid Use Disorder in a Commercially Insured Population in the U.S.Serratore, Catherine 01 January 2019 (has links)
Opioid use disorder (OUD) and opioid overdose are pervasive public health problems in the U.S. Medications for opioid use disorder (MOUD) have been shown effective to reduce OUD morbidity and mortality. Two distinct approaches to MOUD are currently used: agonist therapy (methadone or buprenorphine) or antagonist therapy (naltrexone). Limited information is available about the patterns of use, adherence to therapy, and characteristics of those who use agonist vs. antagonist therapy. The objective of this study is to assess recent trends in MOUD, adherence in use of MOUD, and the characteristics of those who use agonist vs. antagonist therapy in a nationally representative population of commercially insured patients in the U.S.
This retrospective descriptive study utilized data from Truven Marketscan Commercial Claims and Encounters database from years 2011 to 2016. All individuals aged 18 years and older who have a diagnosis of OUD and utilize MOUD at any point during the study period were included. Demographic characteristics of interest included age, gender, geographic region, and type of insurance coverage. Clinical characteristics of interest included diagnosis of OUD and type of MOUD used, including extended – release naltrexone for injection, oral naltrexone, buprenorphine in combination with naloxone, and buprenorphine alone. Descriptive analyses were employed to understand utilization patterns and trends over time and proportion of days covered was used to measure adherence. Frequency and percentage are presented for categorical variables. Adherence of MOUD will be estimated by measuring proportion of days covered. As this study uses de-identified commercial health claims data, it has been determined as not human subjects research by the University of Kentucky’s Office of Research Integrity.
Agonist therapy with buprenorphine or buprenorphine/naloxone was the most common treatment, representing 75.7% of those receiving treatment. Between 2011 and 2016, the percentage of individuals receiving treatment with partial agonist therapy decreased 16.5% to 9.2%, respectively. Meanwhile, the percentage of individuals receiving treatment with antagonist treatment increased from 0.1% in 2011 to 0.3% in 2016. In the analysis of proportion of days covered, all MOUD reported a decrease at both 180 and 365 days. In the commercial population, younger female patients were more likely to be treated with injectable naltrexone. Specifically, in the North Central geographic region, commercial adult patients were more likely to be treated with buprenorphine monotherapy.
Overall, this study found a decrease in use of agonist therapy from 2011 through 2016, with an increase in use of antagonist therapy in the same time period. However, the increase in use of antagonist therapy does not fully account for the decrease in use of agonist therapy, suggesting that since 2011 many patients with OUD still remain untreated. All MOUD types were analyzed and saw a decrease in proportion of days covered, as a measure of adherence, from 2011 to 2016 putting patients at an increased risk for relapse, further complications, emergency visits, and hospitalizations. More information is needed about characteristics of patients who not only seek out treatment for OUD, but also maintain their treatment overtime.
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Healthcare Access, Pregnancy Intention, and Contraceptive Practices Among Reproductive-Aged Women Receiving Opioid Agonist Therapy in Northeast TennesseeLeinaar, Edward, Johnson, Leigh, Yadav, Ruby, Rahman, Abir, Alamian, Arshmam 01 July 2019 (has links)
Objectives: Women with substance use disorders often experience unique challenges to obtaining contraception and adhering to user-dependent methods. As a result, this at-risk population of women tends to have higher than average rates of unintended pregnancy. The objective of this study was to describe contraceptive use, pregnancy intentions, and adequacy of access to reproductive healthcare among women receiving opioid agonist therapy in northeast Tennessee.
Methods: A cross-sectional survey was piloted among female patients aged 18 to 55 years from two opioid agonist therapy clinics. Descriptive analyses were conducted using logistic regression to evaluate the statistical significance of bivariate associations.
Results: Of 91 participants, 84% reported having health insurance, with 70% perceiving having adequate access to health care. More than half had a history of unwanted pregnancy (53%), among whom few (23.1%) reported the consistent use of contraception at time of conception. Although most desired to avoid pregnancy (90%), only 59% of women reported the current use of regular contraception. Most of those not using regular contraception believed that they were not at risk for pregnancy (54.3%).
Conclusions: Although most participants reported adequate access to health care and a desire to avoid pregnancy, few reported the consistent use of regular contraception. Furthermore, misperceptions regarding pregnancy risk were common among participants. Research is needed to identify barriers to contraceptive acceptance and causes of pregnancy risk misperceptions in this population of women at increased risk of unintended pregnancy.
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A feasibility study to test the potential efficacy of a rowing-related yoga program on male varsity competitive rowersKit, Alanna Katharine 07 May 2020 (has links)
The purpose of this present study was to assess the feasibility and determine the potential short-term efficacy of implementing a specific 9-week “Yoga for Rowers” (ROWGA) program on male varsity rowers during a competitive training season. Sixteen competitive male varsity rowers (20.6 ± 2.1 years) were recruited to participate, using a single group, pre-test-post-test, quasi-experimental research design. All participants performed two 60 min ROWGA sessions per week for 9 weeks during their fall competitive season. The primary objectives were to test the efficacy of a ROWGA program in a real-world context by evaluating: 1) the feasibility of implementing the program during the training and competitive season as measured by program adherence; 2) its potential effect on strength by evaluating hip muscle strength acting in the sagittal, frontal, and transverse planes as well as on hip muscle strength ratios between the agonist versus antagonist muscle groups; and 3) its potential effect on hip flexion range of motion (ROM). Two pre-test baseline measurements were performed on all participants over 1- week prior to initiating the ROWGA sessions while a single post-test was conducted following the ROWGA intervention. Intraclass correlation coefficients for ROM and strength were used to determine reliability of measurements by taking the two pre-intervention test scores. Outcome measures included hip flexion range of motion, peak isometric hip muscle forces normalized to body weight, including hip flexors, extensors, abductors, adductors, both internal and external rotators as well as peak isometric agonist-antagonist hip muscle strength ratios. Pre and post peak isometric hip strength measurements were calculated for agonist-antagonist muscle groups within each plane by dividing flexors by extensors, adductors by abductors, and internal by external rotators. Feasibility of the ROWGA program was determined from program attendance and adherence rates.
The adherence rate was considered high with 89% attending all sessions, after adjusting for compulsory competitions. Significant improvements in peak isometric strength were demonstrated for hip flexors, extensors, abductors, and adductors, and external rotators, while a significant reduction for hip flexion ROM was observed. No significant changes in isometric hip muscle strength agonist-antagonist ratios were demonstrated. The results from this research support the feasibility of the ROWGA program in terms of rower’s acceptance, adherence, and the ability to accommodate the time requirements within their schedule as well as potential strength benefits gained. This research could help provide a platform for future large-scale research related to injury prevention in rowing. / Graduate / 2021-04-06
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Examining sucrose subjective response among individuals with opioid use disorderOchalek, Taylor Anne 01 January 2020 (has links)
Aims: Opioid use disorder (OUD) is associated with significant morbidity and mortality, and opioid agonist treatment (OAT) with methadone or buprenorphine represents the most efficacious treatment. However, data suggest that chronic administration of opioids may be associated with significant weight gain, possibly by altering an organism’s perception of and preference for sweet foods. The primary aim of this laboratory study was to rigorously examine sucrose subjective response among adults receiving OAT and a comparison sample without OUD. As secondary outcomes, we also sought to compare the groups on additional baseline characteristics that may influence subjective sucrose response and weight gain during treatment.
Methods: Participants were 40 adults receiving treatment for OUD (OUD+) and a comparison sample of 40 adults without OUD (OUD-). All participants completed an initial screening visit that included questionnaires on eating behaviors, diet and nutrition, recent substance use, and measurement of body mass index. Eligible participants completed two, same-day outpatient laboratory sessions during which they sampled six experimenter-administered concentrations of sucrose solution (0, 0.1, 0.25, 0.5, 0.75, and 1.0M in distilled water) each three times under double-blind counterbalanced conditions. Following each exposure, participants rated the pleasantness and intensity of each sample using 100-point visual analog scales.
Results: OUD+ participants rated sucrose solutions as less pleasant than OUD- participants (p<0.001). However, this effect was limited to the three lowest sucrose concentrations (0, 0.1, 0.25M), and at higher concentrations there were no group differences. There were no between-group differences on ratings of intensity (p=0.35). Given these baseline group differences in placebo (0M) responding, sucrose response was also examined in terms of change from baseline. In this analysis, there was a significant group effect, with a higher magnitude of change in pleasantness ratings and a lower magnitude of change in intensity ratings from 0M in OUD+ vs. OUD- participants (p’s<0.05). With regard to baseline characteristics that may influence sucrose response and eating behavior more generally, the OUD+ group had a higher prevalence of obesity, food insecurity, unhealthy eating behaviors, high sugar consumption, and nutrition knowledge deficits compared to the OUD- group (p’s<0.05).
Conclusion: Data from preclinical and clinical research have suggested that opioid agonist medications may enhance subjective response to sweet flavors. In the present study, OUD+ participants exhibited a higher magnitude of change in pleasantness ratings from placebo compared to OUD- participants. However, this effect was largely driven by pronounced group differences in perceived pleasantness of essentially unsweet solutions. On the outcome of sucrose intensity, findings were more mixed with no consistent differences between OUD+ and OUD- participants. In contrast, group differences were far more pronounced in participants’ daily eating behaviors and nutrition knowledge, with OUD+ participants presenting with a consistently more severe profile. These data highlight the significant risk factors experienced by OUD+ individuals that extend beyond drug-related risks and may inform future scientific and clinical efforts to improve health outcomes in this vulnerable population.
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Pancreatitis: A Potential Complication of Liraglutide?Franks, Andrea S., Lee, Phillip H., George, Christa M. 01 November 2012 (has links)
OBJECTIVE: To review the evidence surrounding a potential association between liraglutide and pancreatitis. DATA SOURCES: A literature search was conducted in MEDLINE (1948-July 12, 2012) and EMBASE (1974-week 27, 2012) using the search terms pancreatitis, liraglutide, and glucagon-like peptide 1/adverse effects. Reference citations from identified publications were reviewed. The manufacturer was contacted and regulatory documents from the Food and Drug Administration website were reviewed for unpublished data related to cases of pancreatitis associated with liraglutide use. STUDY SELECTION AND DATA EXTRACTION: All identified sources that were published in English were considered for inclusion. DATA SYNTHESIS: Eleven cases of pancreatitis have been reported in patients taking liraglutide. Seven were from the LEAD (Liraglutide Effect and Action in Diabetes) studies, 1 was reported in the extension of a clinical trial, and 1 was in an unpublished obesity trial. Two were published postmarketing case reports. Nine of the cases reported were diagnosed as acute pancreatitis, while 2 were classified as chronic pancreatitis. The mean age of the patients was 57.5 years and mean body mass index was 33.92 kg/m2. Six of the 11 cases occurred in male patients. Nine of the patients were white and 1 was African American. In 7 of the cases, onset occurred at liraglutide doses at or above 1.8 mg daily. Common comorbidities included history of pancreatitis, cholelithiasis, and diabetes. One case was fatal. CONCLUSIONS: Pancreatitis is a potential complication with liraglutide therapy. Liraglutide should be used cautiously in patients at risk of pancreatitis (eg, alcohol abuse, history of pancreatitis, cholelithiasis).
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Neurodegeneration und Neuroprotektion bei der Parkinson-Krankheit: Untersuchungen von β-Carbolinen und dem Dopaminagonisten Lisurid in der dopaminergen mesencephalen Primärzellkultur des Mausstammes C57Bl/6Rauh, Juliane 18 March 2008 (has links)
β-Carboline sind heterozyklische Indolalkaloide, die ubiquitär in unserer Umwelt und Nahrung vorkommen, aber auch endogen aus Tryptophan gebildet werden können. Aufgrund der strukturellen Verwandtschaft bestimmter β-Carboline zu dem dopaminergen Neurotoxin MPP+ wird ein möglicher Beitrag zur Pathogenese der Parkinson-Krankheit diskutiert. MPP+ ist seit langem für seine selektive Toxizität gegenüber dopaminergen Neuronen und das Auslösen von Parkinsonsymptomen bekannt. Insbesondere 2,9-DiMe-BC wurde in erhöhter Konzentration in der lumbalen cerebrospinalen Flüssigkeit von Parkinsonpatienten detektiert, jedoch nicht in Kontrollprobanden. Eine Inhibierung von Komplex I der mitochondrialen Atmungskette und eine selektive Toxizität auf DA Neurone konnten nachgewiesen werden. Die genauen Mechanismen des Zelltodes bleiben jedoch ungeklärt. Im Rahmen dieser Arbeit wurden die Mechanismen des Zelltodes, ausgelöst durch 2,9-DiMe-BC, in dopaminergen Primärzellkulturen des Mesencephalons von C57Bl/6-Mäusen untersucht. Drei weitere BC 2-Me-BC, 9-Me-BC und 1,9-DiMe-BC standen für Untersuchungen zur Verfügung. In ersten Experimenten wies 9-Me-BC und 1,9-DiMe-BC keine Toxizität gegenüber DA Neuronen auf. Aufgrund der höheren Toxizität von 2,9-DiMe-BC verglichen mit 2-Me-BC wurden nachfolgende Experimente mit dem zweifach methylierten BC durchgeführt. Durch die Behandlung mit 2,9-DiMe-BC konnte ein höherer Verlust der DA Neurone gegenüber anderen neuralen Zellen festgestellt werden. Eine selektive Aufnahme über den Dopamintransporter und damit verbundene Schädigung der DA Neurone, wie bei MPP+, konnte nicht nachgewiesen werden. Für 2,9-DiMe-BC wurde eine LC50 der DA Neurone von 14,1 µM und für MPP+ von 4,4 µM bestimmt. 2,9-DiMe-BC verursachte in der Gesamtkultur eine erhöhte Entstehung von reaktiven Sauerstoffspezies und eine gesteigerte Laktatproduktion. In diesem Zusammenhang kann eine Hemmung von Komplex I der Atmungskette vermutet werden. Des Weiteren konnte eine Verringerung des mitochondrialen Membranpotentials und des ATP-Gehaltes gemessen werden. Eine Aktivierung des apoptotischen Zelltodes wurde mit einer erhöhten Aktivität von Caspase-3 nachgewiesen. Durch die Behandlung mit 2,9-DiMe-BC wurde in der Primärzellkultur jedoch auch in erhöhtem Maß Nekrose ausgelöst. Dabei wurde eine höhere Sensitivität von jüngeren Kulturen (8. DIV) gegenüber älteren (10. DIV) festgestellt. Genexpressionsanalysen konnten das Auslösen von oxidativem Stress und Apoptose durch 2,9-DiMe-BC bestätigen, da mehrere Gene dieser Prozesse hochreguliert wurden. Des Weiteren wurden Gene reguliert, die im Zusammenhang mit der Hitzeschock-Antwort, Entzündungsprozessen, DNA-Schädigung und Reparatur, Zellalterung und Proliferation stehen. Zusammenfassend lässt sich sagen, dass 2,9-DiMe-BC die Mitochondrienaktivität hemmt, sowohl nekrotische als auch apoptotische Prozesse in der dopaminergen mesencephalen Primärzellkultur auslöst und die Entstehung von oxidativem Stress eine zentrale Rolle spielt. Der zweite Teil dieser Arbeit beschäftigte sich mit der Untersuchung von unerwarteten neuroprotektiven Effekten von 9-Me-BC in der Primärzellkultur. Durch die Behandlung mit 9-Me-BC verringerte sich die LDH-Freisetzung und reduzierte sich die Anzahl der nekrotischen Zellen um 50 %. Nach 24 h konnte eine verminderte Caspase 3-Aktivität gemessen werden, die allerdings nach 48 h im Vergleich zur Kontrolle wieder zunahm. Hier wären längerfristige Untersuchungen zur Klärung dieser Frage anzuschließen. Des Weiteren erhöhte sich der intrazelluläre ATP-Gehalt. Möglicherweise fand eine energieabhängige Verschiebung von Nekrose zu Apoptose statt. Genexpressionsanalysen zeigten, dass verschiedene Gene von inflammatorischen und apoptotischen Signaltransduktionswegen herrunterreguliert wurden. Überraschenderweise erhöhte sich nach der Behandlung mit 9-Me-BC die Anzahl DA Neurone konzentrationsabhängig um bis zu 20 %. Diese Beobachtung ist neu und wurde über noch kein anderes BC berichtet. Der Effekt wurde durch die Inhibierung des DAT aufgehoben und lässt eine DAT-abhängige Aufnahme von 9-Me-BC vermuten. Die signifikante Erhöhung der Anzahl beschränkte sich nur auf DA Neurone, während sich der Gesamtanteil der Neurone nur geringfügig erhöhte und die übrigen Zellen unbeeinflusst blieben. Zusätzlich wurden ein erhöhter intrazellulärer DA-Gehalt und eine gesteigerte Aufnahme von [3H]DA um 20 % nachgewiesen. Die [3H]DA-Aufnahme und morphologische Untersuchungen zeigten funktionale und reife DA Neurone, es wurde aber auch die Theorie der Neuentstehung durch mögliche Differenzierungsprozesse untersucht. Interessanterweise wurde die Genexpression von einem breiten Spektrum neurotropher Faktoren (Shh, Wnt1, Wnt5a) und Transkriptionsfaktoren (En1, Nurr1, Pitx3), die für die Differenzierung und Entwicklung DA Neurone entscheidend sind, durch die Behandlung mit 9-Me-BC hochreguliert. Zusätzlich erhöhte sich die Expression der DA Markergene Aldh1a1, Dat und Th. Dabei war die Hochregulierung der Genexpression bei allen Faktoren bis auf Shh und Wnt1 von der Anwesenheit des BC abhängig. Ein weiterer Aspekt, der auf eine Differenzierung hindeuten könnte, war die verringerte Anzahl mitotischer BrdU-positiver Zellen. Das Erscheinen DA Neurone könnte also auf Differenzierung und Entwicklung von undifferenzierten Zellen oder Vorläuferzellen beruhen. Jedoch wäre auch eine Induktion der TH von vorher TH-negativen Zellen denkbar. Eine weitere Erklärung könnte das Vorherrschen eines dynamischen Gleichgewichts von Absterben und Neuentstehung DA Neurone innerhalb der Primärzellkultur sein und der Absterbeprozess durch protektive Effekte von 9-Me-BC unterbunden wurde. Zukünftige Experimente sollten zu einer weiteren Aufklärung, der diesem Phänomen zu Grunde liegendenen Mechanismen beitragen. Auch durch die Behandlung mit dem Harman 1,9-DiMe-BC erhöhte sich die Anzahl der DA Neurone konzentrationsabhängig, jedoch erwies sich im Vergleich zu 9-Me-BC nur eine Konzentration von 50 µM als signifikant. Innerhalb dieser Arbeit wurden auf Genexpressionsebene mit Hilfe von Microarrays und qRT-PCR mögliche neuroprotektive Effekte des Dopaminagonisten Lisurid im gleichen Zellkulturmodell untersucht. Lisurid gehört zur Substanzklasse der Ergotalkaloide und wird zur Behandlung der Parkinson-Krankheit eingesetzt. Bei Voruntersuchungen in der DA mesencephalen Primärzellkultur wies Lisurid eine protektive Wirkung für DA Neurone gegen Glutamattoxizität auf. Durch qRT-PCR konnten nur 50 % der ausgewählten Gene der Microarraydaten validiert werden. Nach 24 h Behandlung mit Lisurid wurde die Genexpression von dem Transportprotein Transthyretin (Ttr) hochreguliert, dessen erhöhte Biosynthese und Sekretion interessanterweise mit einer Verminderung der Aggregation des Amyloid-β-Proteins assoziiert wird. Die Genexpression der Aldoketoreduktase 1c20 (Ark1c20) wurde um 50 % herrunterreguliert. Die Bedeutung dieses Ergebnisses bedarf weiterer Abklärung, da eine gewebspezifische Expression bisher nur für die Leber gefunden wurde. Das Thyroidhormonrezeptorbindende Protein 3 (Thrap3), die Mitogen aktivierte Kinase Kinase Kinase 12 (Map3k12) und der G-Protein gekoppelte Rezeptor 27 (Gpr27) waren in ihrer Genexpression hochreguliert. Ein Einfluss von Lisurid auf Signaltransduktionswege konnte somit nachgewiesen werden. Des Weiteren wurde durch Lisurid die Expression der Transkriptionsfaktoren NeuroD1 und Tcf3 hochreguliert, die in Differenzierungsprozesse involviert sind. NeuroD1 gilt dabei als proneurales Gen und ist somit möglicherweise an Vorgängen der Neuroprotektion beteiligt. Keines der validierten differentiell exprimierten Gene des 24 h Experimentes war nach einem Behandlungszeitraum von 6 h reguliert. Die Änderungen der Genexpression nach Preinkubation mit Lisurid und anschließender Glutamatbehandlung und Behandlung mit Glutamat allein überschnitten sich weitestgehend. Demnach war vor allem die Glutamatbehandlung für die differentielle Genexpression verantwortlich. Eine zusätzliche Neusynthese von radikalfangenden Proteinen durch Preinkubation mit Lisurid konnte auf Genebene nicht gefunden werden. Es ist jedoch nicht auszuschließen, da eine Regulation auf post-transkriptioneller Ebene möglich ist.
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The Adenosine A(2A) Receptor Agonist CGS 21680 Alleviates Auditory Sensorimotor Gating Deficits and Increases in Accumbal CREB in Rats Neonatally Treated With QuinpiroleBrown, Russell W., Bhide, Pradeep G., Gill, W. Drew, Peeters, Loren D. 01 December 2020 (has links)
Rationale and objective: The adenosine A(2A) receptor forms a mutually inhibitory heteromer with the dopamine D2 receptor, and A(2A) agonists decrease D2 signaling. This study analyzed whether an adenosine A(2A) agonist would alleviate deficits in sensorimotor gating and increases in cyclic-AMP response element binding protein (CREB) in the nucleus accumbens (NAc) in the neonatal quinpirole model of schizophrenia (SZ). Methods: Male and female Sprague-Dawley rats were neonatally treated with saline (NS) or quinpirole HCl (NQ; 1 mg/kg) from postnatal days (P) 1–21. Animals were raised to P44 and behaviorally tested on auditory sensorimotor gating as measured through prepulse inhibition (PPI) from P44 to P48. Approximately 15 min before each session, animals were given an ip administration of saline or the adenosine A(2A) agonist CGS 21680 (0.03 or 0.09 mg/kg). One day after PPI was complete on P49, animals were administered a locomotor activity test in the open field after saline or CGS 21680 treatment, respectively. On P50, the nucleus accumbens (NAc) was evaluated for CREB protein. Results: NQ-treated rats demonstrated a deficit in PPI that was alleviated to control levels by either dose of CGS 21680. The 0.03 mg/kg dose of CGS 21680 increased startle amplitude in males. The 0.09 mg/kg dose of CGS 21680 resulted in an overall decrease in locomotor activity. NQ treatment significantly increased NAc CREB that was attenuated to control levels by either dose of CGS 21680. Conclusions: This study revealed that an adenosine A(2A) receptor agonist was effective to alleviate PPI deficits in the NQ model of SZ in both male and female rats.
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Understanding and treating herpes simplex virus Type 1 corneal infectionsGroleau, Marc 08 1900 (has links)
Le virus de l'herpès simplex de sérotype 1 (HSV-1) est la plus grande cause de l’aveuglement infectieuse dans les pays développés. Les infections cornéennes à HSV-1 ont plusieurs conséquences, comme la difficulté à éliminer l'infection virale et l'inflammation provoquant une plus grande opacité de la cornée. Une infection cornéenne a montré qu'il y a colocalisation des cellules souches et les cellules amplificatrices transitoires avec le virus, mais le HSV-1 était toujours abondant dans le limbe de l'œil. Pour combattre le virus, anciennes publications ont montré que LL37, une cathélicidine humaine, peut réduire la charge virale. Le GF19, un fragment de LL37 modifié pour favoriser la perméabilité, a été capable de réduire la charge virale in vitro et ex vivo, avec la possibilité d'avoir des effets thérapeutique et préventif. Pour combattre les conséquences inflammatoires, un agoniste cannabinoïde CB2r impliqué dans la modulation de la neuroinflammation, TA-A001, a été testé. Des souris ayant reçu des brûlures alcalines pour induire l’inflammation et ils ont montré de meilleurs résultats cliniques avec le TA-A001 qu'avec le véhicule du médicament seul ou un corticostéroïde, la prednisolone. En conclusion, il apparaît que l’HSV-1 infecte rapidement le limbe, que le GF19 a pu réduire la charge virale, et que le TA-A001 a pu réduire l'inflammation en ayant peu d'effets secondaires. Une combinaison des traitements antiviraux et immunosuppresseurs administrés à la cornée pourrait être examinée plus pour combattre contre les infections à HSV-1 dans les yeux. / Herpes Simplex Virus serotype 1 (HSV-1) is the most common cause of infectious blindness in developed countries. Little is known about the early events in HSV-1 ocular infections since clinical symptoms often appear a week after infection. There are two significant consequences of HSV-1 corneal infection: the viral impacts of the disease and the inflammatory impacts. In mouse corneas, after HSV-1 infection, viruses localized in the limbal area of the cornea. However, there was no/little immunohistochemical co-localization with the stem cells or transient amplifying cells. Previous work has shown that LL37, a human cathelicidin, can reduce the viral burden. GF19, a fragment of LL37 with a modification to promote permeability, reduced viral loads in vitro and in ex vivo corneas. To combat the inflammatory consequences of HSV-1 infection, a cannabinoid CB2r agonist implicated in neuroinflammation modulation, TA-A001, was tested. Mice given alkali burns to induce inflammation showed better clinical results with TA-A001 than with the drug’s vehicle alone or a corticosteroid, prednisolone. In conclusion, it appears that HSV-1 quickly infects the limbus, GF19 was able to reduce viral burden, and CB2 agonists such as TA-A001 could reduce inflammation with few side effects. A combination of the anti-viral and immunosuppressant treatments could be a potential HSV-1 treatment.
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