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Effect of morphine on the resistance of the heart to ischemia
Mošovská, Linda ; Neckář, Jan (advisor) ; Žurmanová, Jitka (referee)
2. Abstract Opioids are considered as dangerous and addictive substances, mainly due to synthetic opioids such as heroin. It was discovered, that these substances can play an important role in myocardial ischemia because they can limit the damage of the heart tissue that occurs during a heart attack. Since that heart attack is the most common cardiovascular disease, the protective effect is significant. Cardioprotective effect is mainly mediated through δ opioid receptors, but the few studies have shown cardioprotective effect mediated through κ opioid receptors. The protective effect occurs by activation of opioid receptors by their agonists (eg. morphine or TAN-67), either before ischemia (opioid preconditioning) or before reperfusion (opioid postconditioning). The signaling pathway of cardioprotection include mitochondrial KATP channel, Gi/o proteins, protein kinase C, tyrosine kinases and reactive oxygen species.
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Effect of chronic morphine treatment of rats on myocardial signaling systems regulated by trimeric G-proteins
Škrabalová, Jitka ; Novotný, Jiří (advisor) ; Rudajev, Vladimír (referee)
It has recently been discovered that the effect of morphine can significantly reduce the tissue damage that occurs during myocardial ischemia. The molecular mechanisms by which morphine acts on the heart are still little understood. The aim of this thesis was to monitor the effect of chronic 27-day and 10-day administration of low (1 mg/kg/day) and high (10 mg/kg/ day) doses of morphine on the expression of selected G-protein-coupled receptors (GPCR) and on the expression and activity of adenylyl cyclase (AC). Chronic (27 days) morphine treatment reduced the expression of к-opioids receptors, but 10-day morphine exposure did not influence the expression of these receptors. Assessment of β1- and β2-AR by immunoblot technique did not show any significant change in the expression, but the more accurate determination of β-AR expression using the saturation binding studies revealed that 27-day treatment with high doses of morphine appreciable increased the total number of these receptors. Administration of high doses of morphine led to marked up-regulation of adenylyl cyclase (AC) isoforms V/VI, and the amount of AC decreased proportionally with the time of discontinuation of morphine administration. Low doses of morphine up- regulated AC only during 27-day administration. Chronic morphine exposure did...
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Studies on the molecular mechanisms of cardioprotective effects of morphine
Škrabalová, Jitka ; Novotný, Jiří (advisor) ; Nováková, Olga (referee) ; Hlaváčková, Markéta (referee)
Acute and chronic morphine administration can significantly reduce ischemia- reperfusion injury of the rat heart. However, the molecular mechanisms mediating the protective effect of morphine are not yet fully elucidated. Concurrently, there is a lack of information about the effects of the long-term action of morphine on heart tissue. Therefore, in the first part of the project, we studied the effect of long-term administration of high doses of morphine (10 mg/kg/day, 10 days) on rat heart tissue. In the second part of the project, we investigated the effect of 1 mM morphine on viability and redox state of rat cardiomyoblast cell line H9c2 that was influenced by oxidative stress elicited by exposure to 300 μM tert-butyl hydroperoxide (t-BHP). Our experiments have shown that long-term morphine administration affected neither the amount nor the affinity of myocardial β-adrenergic receptors (β-AR), but almost doubled the number of the dominant isoforms of myocardial adenylyl cyclase (AC) V/VI and led to supersensitization of AC. At the same time, proteomic analyses revealed that long-term morphine administration was associated with significant changes in the left ventricular proteome. In particular, there was an increase in the expression of heat shock proteins (HSP). Increased expression of HSP27...
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A study of molecular interactions of the μ-opioid receptor: the effect of biased ligands
Marková, Vendula ; Novotný, Jiří (advisor) ; Rudajev, Vladimír (referee)
G protein-coupled receptors (GPCRs) are the largest group of membrane-bound receptors. Transmission of signals into the cell interior is mediated through the interactions of these receptors with other signaling molecules. Nowadays, a great attention is devoted to biased ligands which are able to alter the conformation of the receptor in a specific way and thus distinctly affect its function. This diploma thesis was focused on a study of µ-opioid receptor (MOR), which is important in nociception. The aim of this study was to find out, how the activation of MOR by specific biased ligands (morphine, endomorphin-2 and DAMGO) affects the function and the interactions of MOR with potential molecular partners (for example G proteins or β-arrestin) A method of siRNA interference was used to knock down the following selected signaling molecules: Gαi1, Gαi2, Gαi3, Gαz and β-arrestin2. The effect of biased ligands on lateral mobility of MOR in the plasma membrane and on activity of adenylyl cyclase (AC) was examined under these conditions. We observed a possible involvement of Gαz subunit in the lateral mobility of MOR after the effect of morphine and endomorphin-2. The lateral mobility of MOR was significantly increased in cells lacking Gαi2 or Gαi3 or β-arrestin2. In this case the MOR was in inactive state....
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Role of glutamatergic transmission in mechanisms of addiction to morphine.
Moutelíková, Karolína ; Hejnová, Lucie (advisor) ; Červená, Kateřina (referee)
Drugs are used by mankind since ancient times. One group of these substances are opioids. Opioids have antinociceptive effects and can induce euphoria and relaxation as well. A chronic usage of opioids can lead to a development of drug addiction and phenomens like tolerance and sensitization. One of the most used opioids in medicine is morphine. Morphine is isolated from opium of poppy (Papaver somniferum). Direct effect of morphine is mediated via activation of μ- opioid receptors and their signal cascade. It was implicated that the usage of morphine affects other neurotransmmiter systems in the brain and these neurotransmmiter systems play a signifikant role in the development of addiction and other phenomena. One of these systems is an important excitatory brain system - glutamergic system. This bacherol thesis focuses on interrelationship between opioid and glutamatergic systems during addiction.There were described changes in a composition of glutame ionotropic receptors and changes in their expression as well as in expression of metabotropic glutamate receptors. These changes differ in various parts of the brain and in diverse stages of addiction on morphine too. In spite of all diferences, the results of studies indicate that glutamatergic receptors play a significant role in the development...
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Clinical importance and mechanisms of action of morphine and methadone
Slušná, Michaela ; Novotný, Jiří (advisor) ; Hejnová, Lucie (referee)
This bachelor thesis deals with gathering the information regarding the clinical importance of opioid drugs, particularly morphine and methadone, and their mechanism of action. Awareness of health professionals and the general public on opioid is inadequate. This evokes unnecessary anxiety of uninformed patients by the treatment of this kind of drugs. This thesis contains information that should know each worker in the health sector. It deals with pharmacodynamics, which is important for understanding the effects of drugs, both biochemical and physiological as well as pharmacokinetics, which describes how the body compensates for the delivered drug. Usage of morphine and methadone is currently irreplaceable. Morphine is a strong analgesic effective control of pain of different origin. Methadone is used for the substitutive treatment of people addicted to opioids. The side effects occurring during the treatment with opioids are acceptable with regard to severe pain, which is attenuated by opioids.
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Neonatal opioid withdrawal syndrome
Chernova, Alika ; Novotný, Jiří (advisor) ; Brejchová, Jana (referee)
abstinenční syndrom (NAS) je důsledkem užívání opiátů během těhotenství. Závažnost projevů NAS zaleží nejen na typu používané opioidní látky, ale i na gestačním věku a dalších používaných látkách, jako jsou tabák anebo antibiotika. μ různým příznaky NAS a změnami délky pobytu v nemocnici a farmakologické léčby. ráce zahrnuje popis molekulárních principů vzniku rizik užívání těchto látek v období gravidity metody léčby vzniklého neonatálního syndromu Klíčová slova: Neonatální abstinenční syndrom, těhotenství, z
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The effect of morphine withdrawal on the catecholaminergic and serotonergic neurotransmitter system in rat brain
Nováková, Daniela ; Novotný, Jiří (advisor) ; Drastichová, Zdeňka (referee)
The aim of this diploma thesis is to study the effect of morphine withdrawal on catecholaminergic and serotonergic neurotransmitter system in rat brain. Theoretical part of this thesis summarizes basic information known about principles of neurotransmission with focus on the catecholaminergic and serotonergic system, metabolism of its components, their signaling, relevant receptors, their distribution, and especially their effect on morphine dependence and subsequent withdrawal. It also summarizes briefly principles of opioid signaling and outlines the findings yet known about neurochemical analysis of the transmitter systems mentioned above. Experimental part of this thesis is focused on the optimization of the method of high performance liquid chromatography with fluorescence detection and its subsequent use to determine basic components of catecholaminergic and serotonergic neurotransmitter system in samples of different part of brain of rats affected by intraperitoneal administration of morphine sulphate, and its subsequent withdrawal and correspondings unaffected control rats. The expression of selected catecholaminergic receptors in identical samples is also detected. This thesis succesfully implements gradient into the originally isocratic method of high performance liquid chromatography...
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Studies on the molecular mechanisms of cardioprotective effects of morphine
Škrabalová, Jitka
Acute and chronic morphine administration can significantly reduce ischemia- reperfusion injury of the rat heart. However, the molecular mechanisms mediating the protective effect of morphine are not yet fully elucidated. Concurrently, there is a lack of information about the effects of the long-term action of morphine on heart tissue. Therefore, in the first part of the project, we studied the effect of long-term administration of high doses of morphine (10 mg/kg/day, 10 days) on rat heart tissue. In the second part of the project, we investigated the effect of 1 mM morphine on viability and redox state of rat cardiomyoblast cell line H9c2 that was influenced by oxidative stress elicited by exposure to 300 μM tert-butyl hydroperoxide (t-BHP). Our experiments have shown that long-term morphine administration affected neither the amount nor the affinity of myocardial β-adrenergic receptors (β-AR), but almost doubled the number of the dominant isoforms of myocardial adenylyl cyclase (AC) V/VI and led to supersensitization of AC. At the same time, proteomic analyses revealed that long-term morphine administration was associated with significant changes in the left ventricular proteome. In particular, there was an increase in the expression of heat shock proteins (HSP). Increased expression of HSP27...
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Changes of membrane-bound and soluble proteins of frontal rat brain cortex induced by morphine
Ujčíková, Hana
The aim of this Ph.D. thesis was to analyze the morphine-induced changes of frontal brain cortex protein composition in rats exposed to increasing doses of morphine (10-50 mg/kg) for prolonged period of time (10 days). The first part of this work was oriented to the analysis of the phenomenon of hypersensitization/superactivation of adenylyl cyclase (AC), which is regarded as one of the crucial molecular mechanisms causing drastic pathological consequences of drug addiction. The increase of AC activity represents a "compensatory" response and is functionally related to the desensitization of G protein response to prolonged morphine exposure of target cells. The clear desensitization of µ-OR- and δ-OR-stimulated G protein response by morphine was demonstrated in our laboratory by analysis of the dose-response curves of DAMGO and DADLE-stimulated, high-affinity [35 S] GTPγS binding in plasma membranes isolated from frontal brain cortex of rats exposed to morphine according to the same protocol as that used in my Ph.D. thesis (10-50 mg/kg, 10 days). The κ-OR-stimulated [35 S] GTPγS binding was unchanged. It has been determined the amount of all AC isoforms (AC I-IX) in plasma membranes (PM) isolated from control and morphine-treated rats which were sacrificed 24 hours since the last dose of morphine....
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