Spelling suggestions: "subject:"opioides"" "subject:"opioid""
1 |
Identifizierung und Charakterisierung von m-Opioidrezeptor-interagierenden [my-Opioidrezeptor-interagierenden] ProteinenLiang, Yingjian. January 2004 (has links) (PDF)
Magdeburg, University, Diss., 2004.
|
2 |
Struktur - Wirkungsbeziehungen an Bicyclo[3.3.1]nonan-9-on-1, 5-diestern und anderen _63k-selektiven [kappa-selektiven] OpioidenDrosihn, Susanne. January 1999 (has links) (PDF)
Halle, Univ., Diss., 1999. / Computerdatei im Fernzugriff.
|
3 |
Heterogenkatalysierte Verfahren zur Herstellung von pharmazeutischen Wirkstoffen am Beispiel eines Ipriflavon-Vorproduktes, von Cumarinen und neuartigen Opioiden /Wissler, Monika Cornelia. January 2003 (has links)
Zugl.: Aachen, Techn. Hochsch., Diss., 2003.
|
4 |
A infusão contínua de remifentanil não altera a função sistólica e diastólica ventricular esquerda, em cães anestesiados com propofol /Marques, Marcel Gambin January 2017 (has links)
Orientador: Paulo Sérgio Patto dos Santos / Resumo: Com o estudo objetivou-se avaliar os efeitos da infusão contínua de remifentanil na função sistólica e diastólica do ventrículo esquerdo de cães anestesiados com propofol. Foram utilizados seis cães da raça Beagle, dois machos e quatro fêmeas, não castrados, com idade de cinco anos, com peso médio de 13,0 ± 2,5 kg. Os mesmos cães foram submetidos a dois grupos experimentais com intervalo mínimo de sete dias. No primeiro grupo realizou-se infusão contínua de propofol (GP) na taxa de 0,6 mg/kg/minuto, já no segundo utilizou-se infusão contínua de propofol e remifentanil (GPR) nas taxas de 0,6 mg/kg/minuto e 0,3 µg/kg/minuto, respectivamente. As principais variáveis analisadas foram: frequência cardíaca (FC), pressão arterial média (PAM), índice de resistência vascular periférica (IRVP), índice cardíaco Doppler (ICD), fração de encurtamento (FEC), fração de ejeção (FEJ), onda S’, relação E/A e relação E’/A’. Avaliou-se antes da administração dos fármacos (MB) e após 20, 40 e 60 minutos (M20, M40 e M60). Houve redução semelhante dos índices de função sistólica (FEC, FEJ e onda S’) e da PAM em ambos os tratamentos. Entretanto, os valores permaneceram dentro da normalidade para cães anestesiados. Nos animais tratados com remifentanil houve diminuição significativa da FC e ICD. No TPR, a relação E/A permaneceu acima 1,80, todavia, a avaliação Doppler tecidual pulsado (relação E’/A’) mostrou padrão de relaxamento normal. Por meio deste estudo observou-se que o remifentanil na taxa de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Because of its attractive pharmacological characteristics, remifentanil is widely used in human medicine for sedation and anesthesia in critically ill patients, mainly in cardiovascular diseases. Most studies report that this opioid promotes satisfactory analgesia without significant hemodynamic changes, preserving systolic and diastolic function. However, other authors report that depending on the way it is used, remifentanil administration can decrease heart rate, cardiac output and blood pressure, resulting in hemodynamic instability. In veterinary medicine, there are few studies investigating the cardiovascular effects of remifentanil, limiting its safely in the clinical routine. As the increased longevity of dogs, there was a proportional increase in the number of critically ill patients, including patients with cardiovascular diseases, who required safe anesthetic protocols. Therefore, remifentanil may become an excellent option if it is shown to be safe from a cardiovascular point of view. To date, there are no reports using echocardiographic techniques to assess systolic and diastolic function in dogs treated with remifentanil. The aim of this experiment was to evaluate the effects of continuous infusion of remifentanil on left ventricular systolic and diastolic function in dogs anesthetized with propofol. / Mestre
|
5 |
Stereoselektive Synthese konformativ fixierter [kappa]-Agonisten und [delta]-Liganden /Geiger, Christian. January 2006 (has links) (PDF)
Univ., Diss.--Münster (Westfalen), 2006.
|
6 |
Mu-opioid receptor gene variant OPRM1 118A]G a genetic modulator of opioid effects /Oertel, Bruno Georg. Unknown Date (has links) (PDF)
Frankfurt (Main), University, Diss., 2008.
|
7 |
A infusão contínua de remifentanil não altera a função sistólica e diastólica ventricular esquerda, em cães anestesiados com propofol / Continuous infusion of remifentanil does not impair left ventricular systolic and diastolic function, in dogs anesthetized with propofolMarques, Marcel Gambin [UNESP] 05 June 2017 (has links)
Submitted by Marcel Gambin Marques null (maarcel_maarques@hotmail.com) on 2017-06-07T17:45:13Z
No. of bitstreams: 1
Dissertação de Mestrado.pdf: 566802 bytes, checksum: e421923c94d9b7300cb073c9e8260a2d (MD5) / Rejected by Luiz Galeffi (luizgaleffi@gmail.com), reason: Solicitamos que realize uma nova submissão seguindo a orientação abaixo:
O arquivo submetido não contém o certificado de aprovação.
O arquivo submetido está sem a ficha catalográfica.
A versão submetida por você é considerada a versão final da dissertação/tese, portanto não poderá ocorrer qualquer alteração em seu conteúdo após a aprovação.
Corrija esta informação e realize uma nova submissão com o arquivo correto.
Agradecemos a compreensão. on 2017-06-07T18:42:44Z (GMT) / Submitted by Marcel Gambin Marques null (maarcel_maarques@hotmail.com) on 2017-06-08T18:11:42Z
No. of bitstreams: 1
Dissertação de Mestrado.pdf: 826139 bytes, checksum: 87d31a7a67665bfd5570805132111678 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-06-13T13:28:20Z (GMT) No. of bitstreams: 1
marques_mg_me_araca.pdf: 826139 bytes, checksum: 87d31a7a67665bfd5570805132111678 (MD5) / Made available in DSpace on 2017-06-13T13:28:20Z (GMT). No. of bitstreams: 1
marques_mg_me_araca.pdf: 826139 bytes, checksum: 87d31a7a67665bfd5570805132111678 (MD5)
Previous issue date: 2017-06-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Com o estudo objetivou-se avaliar os efeitos da infusão contínua de remifentanil na função sistólica e diastólica do ventrículo esquerdo de cães anestesiados com propofol. Foram utilizados seis cães da raça Beagle, dois machos e quatro fêmeas, não castrados, com idade de cinco anos, com peso médio de 13,0 ± 2,5 kg. Os mesmos cães foram submetidos a dois grupos experimentais com intervalo mínimo de sete dias. No primeiro grupo realizou-se infusão contínua de propofol (GP) na taxa de 0,6 mg/kg/minuto, já no segundo utilizou-se infusão contínua de propofol e remifentanil (GPR) nas taxas de 0,6 mg/kg/minuto e 0,3 µg/kg/minuto, respectivamente. As principais variáveis analisadas foram: frequência cardíaca (FC), pressão arterial média (PAM), índice de resistência vascular periférica (IRVP), índice cardíaco Doppler (ICD), fração de encurtamento (FEC), fração de ejeção (FEJ), onda S’, relação E/A e relação E’/A’. Avaliou-se antes da administração dos fármacos (MB) e após 20, 40 e 60 minutos (M20, M40 e M60). Houve redução semelhante dos índices de função sistólica (FEC, FEJ e onda S’) e da PAM em ambos os tratamentos. Entretanto, os valores permaneceram dentro da normalidade para cães anestesiados. Nos animais tratados com remifentanil houve diminuição significativa da FC e ICD. No TPR, a relação E/A permaneceu acima 1,80, todavia, a avaliação Doppler tecidual pulsado (relação E’/A’) mostrou padrão de relaxamento normal. Por meio deste estudo observou-se que o remifentanil na taxa de 0,3 µg/kg/min não alterou a função sistólica e diastólica do ventrículo esquerdo em cães hígidos anestesiados com propofol, mostrando-se seguro, sob o ponto de vista cardiovascular. / Because of its attractive pharmacological characteristics, remifentanil is widely used in human medicine for sedation and anesthesia in critically ill patients, mainly in cardiovascular diseases. Most studies report that this opioid promotes satisfactory analgesia without significant hemodynamic changes, preserving systolic and diastolic function. However, other authors report that depending on the way it is used, remifentanil administration can decrease heart rate, cardiac output and blood pressure, resulting in hemodynamic instability. In veterinary medicine, there are few studies investigating the cardiovascular effects of remifentanil, limiting its safely in the clinical routine. As the increased longevity of dogs, there was a proportional increase in the number of critically ill patients, including patients with cardiovascular diseases, who required safe anesthetic protocols. Therefore, remifentanil may become an excellent option if it is shown to be safe from a cardiovascular point of view. To date, there are no reports using echocardiographic techniques to assess systolic and diastolic function in dogs treated with remifentanil. The aim of this experiment was to evaluate the effects of continuous infusion of remifentanil on left ventricular systolic and diastolic function in dogs anesthetized with propofol. / FAPESP: 2015/01806-4
|
8 |
Opioidrezeptoren auf neutrophilen Granulozyten physiologische und pathophysiologische RegulationsprozesseSchmidt, Alexander Robert January 2009 (has links)
Zugl.: Giessen, Univ., Diss., 2009
|
9 |
Synthese, Stereochemie und pharmakologische Charakterisierung von 3,7-Diazabicyclo[3.3.1]nonan Derivaten als selektive kappa-Agonisten / Synthesis, stereochemistry and pharmacological characterization of 3,7-diazabicyclo[3.3.1]nonane derivates as selective kappa-agonistsProjahn, Holger January 2005 (has links) (PDF)
In der vorliegenden Arbeit wird die Synthese von verschiedenen bicyclischen Substanzklassen gemäß des folgenden Syntheseschemas beschrieben. Es wurden verschiedene 2,4-di-(2-pyridyl)- oder 2,4-di-(3-fluorphenyl)-substituierte 9-Oxo-3,7-diazabicyclo[3.3.1]nonan-1,5-dicarbonsäurediester (9-Oxo-BNDS: 21-25, 27-55) synthetisiert, welche 1. teilweise als Vorstufen zur Synthese von 1,5-Di-(hydroxymethyl)-3,7-diazabicyclo[3.3.1]nonan-9-olen (Triole: 56-65) eingesetzt wurden, 2. teilweise als Vorstufen zur Synthese von 9-Hydroxy-3,7-diazabicyclo[3.3.1]nonan-1,5-dicarbonsäuredimethylestern (9-OH-BNDS: 66-69) verwendet wurden, die ihrerseits zu 9-O-Acyl-3,7-diazabicyclo[3.3.1]nonan-1,5-dicarbonsäuredimethylestern (9-OAc-BNDS: 70-76) umgesetzt wurden oder 3. als Vorstufe zur Synthese der 9-Oxo-3,7-diazabicyclo[3.3.1]nonan-1,5-dicarbonsäure 26 dienten. Die 9-Oxo-BNDS wurden aus den kommerziell erhältlichen Aceton-1,3-dicarbonsäuredimethyl- (ADS-Me), -ethylester (ADS-Et) oder den ADS 1-3 synthetisiert, die ihrerseits ausgehend von ADS-Me und den entsprechenden Alkoholen durch Umesterung hervorgehen. Die ADS wurden durch eine Mannich-Kondensation mit zwei Äquivalenten eines aromatischen Aldehyds und einem Äquivalent eines primären Amins in MeOH zu den entsprechenden 4-Piperidon-3,5-dicarbonsäureestern (PDS: 4-20) umgesetzt, die wiederum ebenfalls durch eine Mannich-Kondensation mit zwei Äquivalenten Formaldehyd und einem Äquivalent eines primären Amins in THF oder Aceton zu den entsprechenden 9-Oxo-BNDS reagieren. Dieser Syntheseschritt wurde hinsichtlich Ausbeute, Vereinfachung und Beschleunigung der Aufarbeitung optimiert. Die Stereochemie der so erhaltenen 9-Oxo-BNDS, die in Abhängigkeit vom Substitutionsmuster als cis- oder trans-Isomere entstehen, konnte mittels NMR-Spektroskopie aufgeklärt werden. Der 1,5-Dibenzylester 25 konnte durch katalytische Hydrierung mit Pd/C als Katalysator in EtOAc zur freien 1,5-Dicarbonsäure 26 umgesetzt werden. Die Triole 56-62 wurden ausgehend von den 9-Oxo-BNDS HZ2, 3FLB, 21-24, 28, 33 in einer Eintopfsynthese mittels NaBH4 in THF/MeOH durch Reduktion hergestellt. Die N3- und/oder N7-benzyl-substituierten Triole 57-59 wurden mittels katalytischer Hydrierung mit Pd/C als Katalysator in MeOH zu den entsprechenden NH-substituierten Triolen 63-65 umgesetzt. Mit Hilfe von selektiven 1D-NOESY-Messungen konnte die Stereochemie der Triole bezüglich der Stellung der Hydroxygruppe an C9 zugeordnet werden. Die 9-OH-BNDS 66-69 wurden durch Reduktion der entsprechenden 9-Oxo-BNDS HZ2, 3FLB, 32, 33 mit Na(CN)BH3 in MeOH synthetisiert. Die Reduktion verläuft nicht stereoselektiv, sodass die dabei entstehenden 9-OH-BNDS als Diastereomerengemische durch syn/anti-Isomerie der C9-OH-Gruppe anfallen. Das Diastereomerengemisch 66 konnte durch präparative Säulenchromatographie in die beiden reinen Isomere 66a (anti) und 66b (syn) getrennt werden. Das Gemisch 67 konnte durch Entwicklung einer HPLC-Methode und anschließender Übertragung auf ein Flashchromatographiesystem präparativ in die diastereomerenreinen Isomere 67a (anti) und 67b (syn) getrennt werden. Die stereochemische Zuordnung der Konfiguration an C9 wurde durch selektive 1D-NOESY-Messungen erreicht. Die Synthese der 9-OAc-BNDS 70-76 erfolgte durch Umsetzen des entsprechenden 9-OH-BNDS 66a, 67a, 67-69 mit einer äquimolaren Menge eines entsprechenden Carbonsäurechlorids und DBU als Hilfsbase in CHCl3. Im Fall der Synthese von Verbindung 76 musste das eingesetzte Decanoylchlorid mit Zinkstaub aktiviert werden. Die Zuordnung der Stereochemie der so erhaltenen Verbindungen basiert auf selektiven 1D-NOESY-Messungen. Die Verbindungen 25-27, 31, 56, 60, 63-66, 66a/b, 67, 67a/b, 70a, 71, 71a wurden auf pharmakologische Affinität zum kappa-Opioidrezeptor (OR) untersucht. Dadurch konnten die Verbindungen 71, 71a und 67a/b als hochaffine Liganden des kappa-OR identifizert werden. Durch die qualitative Analyse der Struktur-Wirkungs-Beziehungen, die auf dem Vergleich der pharmakologischen Daten dieser Arbeit und vorangegangener Arbeiten basiert, konnten folgende Anforderungen an selektive Liganden des kappa-OR mit 3,7-Diazabicyclo[3.3.1]nonan-Grundgerüst ermittelt werden: 1. Das Grundgerüst sollte an Position 2/4 mit 2-Pyridylresten substituiert sein. 2. An Position N3 und N7 dürfen keine Substituenten angebracht sein, die größer als ein Methylrest sind. 3. Das Molekül sollte an Position 1/5 mit Methylestergruppen versehen sein. 4. Der 3,7-Diazabicyclus kann an Position 9 eine -OH, -OAc oder möglicher-weise auch entsprechende, sterisch anspruchsvollere Funktionen besitzen. 5. Die Stellung des Substituenten an Position 9 sollte vorzugsweise anti-konfiguriert sein, bezogen auf den höher substituierten Piperidinring. / The aim of the present work was the synthesis of several bicyclic compound classes as described in the following synthetic pathway. Various 2,4-di-(2-pyridyl)- or 2,4-di-(3-fluorphenyl)-substituted 9-oxo-3,7-diazabicyclo[3.3.1]-nonan-1,5-dicarboxylates (9-Oxo-BNDS: 21-25, 27-55) have been synthesized, which 1. were partially used as templates for the synthesis of 1,5-di-(hydroxymethyl)-3,7-diazabicyclo[3.3.1]nonan-9-oles (trioles: 56-65), 2. were partially used as starting compounds for the synthesis of dimethyl-9-hydroxy-3,7-diazabicyclo[3.3.1]nonan-1,5-dicarboxylates (9-OH-BNDS: 66-69), which in turn were used for the preparation of dimethyl-9-O-acyl-3,7-diazabicyclo[3.3.1]nonan-1,5-dicarboxylates (9-OAc-BNDS: 70-76), 3. served as starting compound for the synthesis of the 9-oxo-3,7-diazabicyclo-[3.3.1]nonan-1,5-dicarboxylic acid 26. The 9-Oxo-BNDS were prepared starting from the commercially available di-methyl- (ADS-Me) or diethylacetone-1,3-dicarboxylate (ADS-Et) or the ADS 1-3, which themselves were synthesized by transesterification of ADS-ME with the corresponding alcohols. The ADS were converted to the respective 4-piperidon-3,5-dicarboxylates (PDS: 4-20) by means of a Mannich-condensation with two equivalents of an aromatic aldehyde and one equivalent of a primary amine in MeOH as a solvent. The PDS were subjected to a second Mannich-condensation with two equivalents of formaldehyde and one equivalent of a primary amine in THF or acetone to form the corresponding 9-Oxo-BNDS. This step was optimized with respect to the yields, simplification and acceleration of the refurbishment. The stereochemistry of the so achieved 9-Oxo-BNDS, which can emerge as cis- or trans-isomers dependent on their substitution pattern, was elucidated by means of NMR-spectroscopy. The dibenzylcarboxylate 25 could be converted to the free dicarboxylic acid 26 by means of catalytic hydrogenation with Pd/C as catalyst in EtOAc as solvent. The trioles 56-62 were synthesized starting from the the 9-Oxo-BNDS HZ2, 3FLB, 21-24, 28, 33 in a one-pot-reduction-step by means of NaBH4 in THF/MeOH. The N3- and/or N7-benzyl-substituted trioles 57-59 were converted to the respective NH-substituted trioles 63-65 by catalytic hydrogenation with Pd/C in MeOH. The assignment of the hydroxy-group at C9 was achieved via selective 1D-NOESY measurements. The 9-OH-BNDS 66-69 were perpared by reduction of of the appropriate 9-Oxo-BNDS HZ2, 3FLB, 32, 33 with Na(CN)BH3 in MeOH. The reduction does not proceed in a stereoselective manner, which in consequence leads to the isolation of syn/anti-isomers with respect to the hydroxygroup at C9. The isomeric mixture 66 could be resolved into both pure isomers 66a (anti) and 66b (syn) by means of preparative column chromatography. The isomeric mixture 67 was separated in order to obtain the pure isomers 67a (anti) and 67b (syn) by preparative flash-chromatography. The stereochemical assignment of the hydroxygroup at C9 was accomplished by selective 1D-NOESY measurements. The synthesis of the 9-OAc-BNDS 70-76 was carried out by reaction of the respective 9-OH-BNDS 66a, 67a, 67-69 with an equimolar amount of the congruent acylchloride and DBU as an auxilary base in CHCl3. In the case of compound 76 the deployed decanoylchloride had to be activated with zinc dust. The stereochemical assignment of the so obtained compounds is based on selective 1D-NOESY measurements. The compounds 25-27, 31, 56, 60, 63-66, 66a/b, 67, 67a/b, 70a, 71, 71a were investigated with respect to their pharmacological affinity to the kappa-opioid receptor (OR). Compounds 71, 71a and 67a/b were identified to be highly affine ligands to the kappa-OR. By means of the analysis of structure-affinity-relationships, which are based upon the comparison of the pharmacological data of the present work and previous findings, the following prerequisites for high affinity towards the kappa-OR were derived for compounds bearing the 3,7-diazabicyclo[3.3.1]nonan-skeleton: 1. The skeleton at position 2/4 should be substituted by 2-pyridyl moieties. 2. No substituents being larger than a methyl-group should be attached to the nitrogens N3 and N7. 3. The molecule should carry a methyl carboxylate at positions 1/5. 4. The 3,7-diazabicycle may possess a -OH, -OAc or probably a respective, even sterically larger substituent at position 9. 5. The orientation of the substituent at position 9 should be preferably of anti-configuration according to the higher substituted piperidine ring.
|
10 |
Opioid receptors as therapeutic targets for nociceptor specific regional analgesia / Opioidrezeptoren als therapeutisches Target einer nozizeptionsspezifischen RegionalanalgesieMambretti, Egle Maria January 2015 (has links) (PDF)
Opioids have been, since centuries, the gold standard for pain treatment and relief. They exert their effects after binding to opioid receptors (OP) that are expressed and functional in the central (CNS) and peripheral nervous system (PNS). As their systemic application has many side effects, including sedation and respiratory depression, a peripheral application of opioids and selective targeting of µ-OP (MOP) in nociceptive axons would be extremely beneficial. MOP presence and function has been conclusively demonstrated at nerve terminals; however it is still controversial whether functional MOPs are available on the membrane of peripheral nociceptive axons to mediate opioid-induced antinociception. While under pathologic conditions (i.e. nerve injury) exogenous as well as endogenous MOP agonists applied at the damaged nerve can elicit potent antinociception or anti-allodynia, under physiological conditions no antinociception was seen in rats. This could be caused by either a lack of functional opioid receptors in the axonal membranes or by the inability of injected opioids to cross the intact perineurial barrier and to reach nociceptors. Previous behavioral test results showed an antinociceptive effect (up to 5h) following perisciatic application of the hydrophilic DAMGO (MOP agonist) if coinjected with hypertonic saline solution (HTS; 10% NaCl), a treatment suited to open the perineural barrier. The effect was inhibited by naloxone, a MOP antagonist, documenting its specific action via MOP. Fentanyl, a lipophilic opioid, elicited an effect, which was enhanced by HTS treatment, indicating that HTS may act not only on the barrier but also directly on axonal MOP presence and/or functionality. To provide a basis for testing this hypothesis, the present work was designed to study the axonal localization of MOP in experimental animals under different conditions using molecular and morphological methods.
Initially four different commercial antibodies were tested for MOP detection. Immunoreactions with these antibodies specifically detected MOP in the hippocampus and in amygdala, while in the peripheral nervous system the reactions showed varying labeling patterns pointing towards less specificity with low signal-to-noise ratio. Double labelling with calcitonin gene related peptide (CGRP), a neuropeptide expressed in sensory fibers, with the non-compacted myelin marker S100 or with the neuronal marker PGP9.5 documented significant immunoreaction signals outside sensory nerve fibers. Therefore, none of these antibodies appeared suitable. Taking advantage of a new commercial monoclonal rabbit antibody (RabMAb) and of genetically modified mice in which the fluorescent protein mcherry was inserted in the C-tail of MOP (MOP-mcherry knock-in mice), MOP fusion protein expression in rat and mouse CGRP+ sciatic nerve fibers and fiber bundles was confirmed by immunofluorescence labeling. Immunoelectron microscopic analysis indicated MOP/MOP-mcherry-localization in the cytoplasm and the membranes of unmyelinated axons organized in Remak bundles. Both antibodies detected bands of appropriate size in Western Blot in the CNS and additional larger bands in the PNS. Quantitative analyses 60 min after HTS-treatment revealed no change in MOP mRNA in the sciatic nerve and DRG as well as no change in MOP immunoreactivity in the sciatic nerve. Thus, the opioid-induced long lasting antinociception enhanced by perisciatic injection of HTS were not due to a sustained increased MOP expression or content in sensory, putative nociceptive axons.
In summary, the current study succeeded to unequivocally document the presence of MOP protein in intact sensory axons of rat and mouse sciatic nerve. Thus, axonal MOPs may indeed mediate antinociceptive opioid effects observed in behavioral studies in naive animals possibly via activation of potassium or calcium channels. As HTS treatment does not lead to a sustained increase in axonal MOP protein or MOP mRNA expression, other mechanisms might enhance MOP function, including inhibition of MOP recycling or changes in functional coupling. Future studies should further explore the axonal mechanisms of antinociception by opioids and enhancing treatments. / Opioide sind seit Jahrhunderten der Goldstandard für die Schmerzbehandlung. Sie entfalten ihre Wirkung nach der Bindung mit Opioidrezeptoren (OP), die im zentralen (ZNS) und peripheren (PNS) Nervensystem exprimiert und funktionell sind. Da die systemische Anwendung viele Nebenwirkungen hat, wie die Beruhigung und Atemdepression, wäre eine Anwendung von Opioiden und die gezielte Targeting von µ-OP (MOP) in nozizeptiven Axone in Rahmen einer Regionalanalgesie besser. Die Anwesenheit und die Funktionalität der MOP wurden zwar schon in Nervenendungen gezeigt, aber es ist noch strittig, ob funktionelle MOP in der Membran von peripheren nozizeptiven Axonen sind, um opioid-induzierte Antinozizeption zu vermitteln. Während bei Erkrankungen der Nerven (z.B. traumatische Nervenbeschädigung) exogene und endogene MOP-Agonisten Antinozizeption und Antiallodynie bewirken, konnte in gesunden Ratten kein Effekt bei perineuraler Injektion am Nerven beobachtet werden. Dies könnte entweder durch einen Mangel an funktionellen OP in axonalen Membranen verursacht sein. Alternativ könnte die mangelde Penetration der injizierten Opioide durch die Barriere des Perineuriums verantwortlich sein, die es verhindert, dass die Opioide die Nozizeptoren erreichen. Vorherige Ergebnisse aus Schmerzverhaltenstests zeigten eine Anhebung von mechanischen nozizeptiven Schwellen (bis 5 h) nach perineuraler Anwendung des hydrophilen MOP-Agonisten DAMGO, wenn dieser mit einer hypertonen Lösung (HTS; 10% NaCl) ko-injiziert war. Denn dies ist eine geeignete Behandlung, die die Barriere des Perineuriums öffnet. Der Effekt wurde von Naloxon, einem MOP-Antagonist, gehemmt, was eine spezifische Wirkung via MOP unterstützt. Die Wirkung von Fentanyl, einem lipophilen Opioid, wurde ebenfalls durch die HTS-Behandlung verbessert. Das führt zu unserer Hypothese, dass HTS nicht nur die Schranke öffnet, sondern auch direkt Expression und/oder Funktionalität von axonalen MOP verbessert. Um eine Grundlage für die Untersuchung dieser Hypothese zu schaffen, war das Ziel dieser Arbeit, die axonale MOP bei Versuchstieren unter verschiedenen Bedingungen mit molekularen und morphologischen Methoden zu charaktiersieren.
Am Anfang wurden vier verschiedene kommerzielle Antikörper für die Erkennung der MOP getestet. Immunreaktionen mit diesen Antikörpern wiesen spezifisch MOP in dem Hippocampus und in der Amygdala nach, während im peripheren Nervensystem die Immunreaktion veränderliche Markierungsmuster und weniger Spezifität mit einem ungünstigeren Signal-zu-Hintergund Verhältnis zeigte. Die Doppelmarkierung mit calcitonin gene-related peptide (CGRP), einem Neuropeptid, das in sensorischen Fasern exprimiert ist, mit dem Marker für non-compacted Myelin S100 oder mit dem neuronalen Marker PGP9.5, bestätigte ein reproduzierbares Färbemuster außerhalb sensorischer Nervenfasern. Deshalb war keiner dieser Antikörper geeignet.
Mit der Anwendung eines neuen kommerziell erhältlichen monoklonalen Kaninchen Antikörpers (RabMAb) gegen MOP sowie gentechnisch veränderten Mäusen, bei denen das fluoreszierende Protein mCherry in das C-terminale Ende von MOP eingefügt wurde (MOP-mcherry knock-in Mäusen), wurden MOP und das MOP-Fusionprotein im CGRP+ im Ischiasnerv und Fasernbündeln durch Immunfluoreszenzmarkierung von Ratten und Mäuse bestätigt. Die immunelectron-mikroscopische Analyse zeigte MOP/MOP-mcherry im Zytoplasma und der Membran unmyelinizierter Axone, die in Remak Bündlen organisiert sind. Beide Antikörper erkannten Banden in richtige Größe in Western Blot in ZNS und mehrere größere Banden in PNS. Quantitative Analysen 60 min nach HTS-Behandlung zeigten keine Veränderung in MOP mRNA in dem Ischiasnerv und Hinterwurzelganglion sowie keine Veränderung in der MOP-Immunreaktivität in dem Ischiasnerv. Daher müssen noch weitere Ursachen für die verbesserte Wirkung von Opioiden am Nerven nach HTS in Betracht gezogen werden.
Zusammenfassend konnte diese Studie die MOP-Proteins in intakten sensorischen Axonen des N. ischiadicus der Ratte und Maus eindeutig nachweisen. Axonale MOPs könnten über Kaliumkanäle oder Calciumkanäle in den Verhaltenstests bei naiven Tiere antinozizeptiv wirken. Da die HTS Behandlung zu keiner deutlichen Steigerung von axonalem MOP-Protein führen kann, sollten anderen Mechanismen wie MOP-Recycling oder Veränderung der intrazellulären Singaltransduktion untersucht werden, die die Funktionalität von MOP erhöhen. Zukünftige Studien ferner den genauen Mechanismus klären, wie axonal Opioide antinozizeptiv wirken, um so die Behandlung von Schmerzen mit Regionalanalgesie weiter zu verbessert.
|
Page generated in 0.0397 seconds