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Potential role of opioids in neuroprotection
Gebauer, Martin ; Novotný, Jiří (advisor) ; Rudajev, Vladimír (referee)
The opioids have been used by mankind for more than two millennia, but effect and mechanism of their action on the cells has been unveiling in the last few decades. The mechanism itself is often still unknown, but its effect is observed only. There are several groups of opioid receptors which are able to bind opioids. These groups are characterized by their differe nt affinity to opioids, in some cases by their different effects on cells and by their representation in the various areas in the CNS. Thus, the effects induces by these opioid are very different in many cases. This thesis summarizes the current knowledge about coronary heart disease and the potential of opioids for the prevention and their effect during ischemia, also summarizes the effects of morphine on the CNS. During ischemia δ-opioid receptors play a major role, because they inhibit or block the proapoptotic effects of ischemia on many levels. These receptors are also involved in inducing and maintaining the animal hibernation and protect animal's body against very harmful effects of hibernation, e.g lack of oxygen and nutrients. Morphine is opioid which has been used as anesthetic for longest time. It is well-known opioid and it has the most known derivates. This thesis also summarizes most significant effects of morphine on...
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The effect of morphine on the distribution of signaling molecules of the opioid system in lipid rafts prepared from rat heart
Ladislav, Marek ; Novotný, Jiří (advisor) ; Rudajev, Vladimír (referee)
Morphine is an opioid agonist, which can exert cardioprotective effects under certain conditions. Lipid rafts are considered important platforms for membrane organization of signaling proteins and, therefore, these structures could play a role in the effects of morphine, which acts through the opioid receptors. The aim of this thesis was to investigate the distribution of the main components of the opioid receptor and Gi/o-mediated signaling pathway in lipid rafts isolated from rat myocardium, which was affected by various doses of morphine. Because we used different isolation techniques with different solubilization agents (Triton X-100, CHAPS, cholate and sodium carbonate) for preparation of lipid rafts, it was of interest to characterize more closely these preparations. Another aim of this study was to investigate how different methods of isolating these structures affect activity of the key target enzyme of the opioid signaling pathway, i.e. adenylyl cyclase. The presence of signaling molecules of the Gi/o/AC pathway of the opioid system in membrane rafts was confirmed and the distribution of selected proteins was dependent on the type of extractant. We also observed the effect of morphine on the localization of proteins in lipid rafts. Different extractants provided different degree of...
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The effect of morphine on expression and distribution of the alpha and beta subunits of trimeric G-proteins in the rat myocardium
Bartoňová, Iveta ; Novotný, Jiří (advisor) ; Roubalová, Lenka (referee)
Morphine is a clinically very important drug from the opioid group that is used for treatment of severe pain because of its strong analgetic effect. Opioid receptors mediating the morphine effect interact with the Gi/o class of trimeric G-proteins. Opioid receptors also occur in heart tissue and morphine can thus potentially exercise its effect on the function of this organ. The major aim of this project was to pursue consequences of long-term treatment with morphine on expression and distribution of selected heterotrimeric G-protein subunits in the rat heart. Potential cardioprotective effects of this drug have also been studied. Laboratory rats of the Wistar strain were treated with morphine (1 mg/kg/day or 10 mg/kg/day) for 10 or 28 days. The control group was treated with saline solution. Prolonged treatment with morphine did not cause any effects on Gs, Gi, Gz, Gq/11, G subunits, but the expression of Go rather decreased. The results of subsequent experiments showed that prolonged administration of high doses of morphine may reduce the area affected by infarction and reduced the frequency of ventricle arrhythmias depending on dose and duration of morphine administration. Key words: morphine, myocardium, opioid receptor, G-protein subunits, infarction.
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Potential role of opioids in neuroprotection
Gebauer, Martin ; Novotný, Jiří (advisor) ; Rudajev, Vladimír (referee)
The opioids have been used by mankind for more than two millennia, but effect and mechanism of their action on the cells has been unveiling in the last few decades. The mechanism itself is often still unknown, but its effect is observed only. There are several groups of opioid receptors which are able to bind opioids. These groups are characterized by their differe nt affinity to opioids, in some cases by their different effects on cells and by their representation in the various areas in the CNS. Thus, the effects induces by these opioid are very different in many cases. This thesis summarizes the current knowledge about coronary heart disease and the potential of opioids for the prevention and their effect during ischemia, also summarizes the effects of morphine on the CNS. During ischemia δ-opioid receptors play a major role, because they inhibit or block the proapoptotic effects of ischemia on many levels. These receptors are also involved in inducing and maintaining the animal hibernation and protect animal's body against very harmful effects of hibernation, e.g lack of oxygen and nutrients. Morphine is opioid which has been used as anesthetic for longest time. It is well-known opioid and it has the most known derivates. This thesis also summarizes most significant effects of morphine on...
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The study of membrane receptors by radioligands binding
Rejhová, Alexandra ; Hudeček, Jiří (advisor) ; Hejnová, Lucie (referee)
Drug addiction, opiates respectively, is a social problem which seriousness is currently on the rise. One of key elements causing addiction is tolerance to increasing doses of drug causing abstinence syndrome during withdrawal and craving. Opioid receptors are members of a large group of receptors coupled with heterotrimeric G-proteins (GPCR), whose properties can be investigated using agonist- stimulated binding [35 S] GTPγS. Many extracellular signals are transferred into a cell through GPCR. Opioid receptor agonists inhibit the activity of adenylyl cyclase and are coupled with G-protein group Gi/Go. This work is devoted to the study of changes in isolated plasma membranes of rat forebrain containing opioid receptors of healthy subjects with membranes acquired from morphine addicted subjects. The rats were long-term morphine treated in increasing doses, to develop the dependency. The comparison is done firstly by binding of [3 H]ouabain to Na,K-ATPase, which proves to be a negative standard of changes, secondly by binding [35 S]GTPγS to G-proteins, thereby providing the functional activity of G-protein in stimulating the binding by the agonist of δ-opioid receptors DADLE or agonist of µ-opioid receptors DAMGO. Furthermore, it has been studied the influence of prostaglandin E1 on binding [35...
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