Thesis (doctoral)--Umeå Universitet, Sweden, 1991. / Extra t.p. with thesis statement inserted. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The cAMP-second messenger hypothesis for β-adrenoceptor-induced relaxation of uterine smooth muscle was tested in high-K+ depolarized rat uterus. At 10⁻⁸ M concentration, Isoproterenol, a β -adrenergic agonist, could cause relaxation of the depolarized uterus without Increasing tissue cAMP levels. Further, although increases in cAMP levels were associated, in some cases, with -isoproterenol (10⁻⁸ M or 10⁻⁴ M)-Induced relaxation, there was no quantitative correlation between the Increases in cAMP and relaxation. Pretreatment of the tissue with a phosphodiesterase Inhibitor, RO 20-1724 (10⁻⁴ M), did not potentiate the relaxation response to Isoproterenol. These results suggested that there Is no simple cause and effect relationship between β -adrenoceptor-Induced Increases in cAMP levels and relaxation in uterine smooth muscle. The dissociation between cAMP and relaxation found ln the present study was also extended to cGMP, since no changes in cGMP levels were observed with isoproterenol-induced relaxation. It is generally accepted that the ionic environment of the cell affects the cellular responses of the tissue. It was demonstrated that hlgh-K*" depolarization of uterine smooth muscle caused an impairment of the ability of isoproterenol to induce cAMP accumulation. This was found to be related to Increased Ca++-Influx known to occur during depolarization. This Is because pretreatment of the tissue with 10⁻⁵M D-600, an Inhibitor of Ca++-lnflux, restored the stimulation of cAMP by Isoproterenol ln the depolarized muscle to a level similar to that observed ln non-depolarized muscle. Furthermore, there was an Inverse relationship between [ca++] ex in the depolarizing medium (range 0.9 to 7.2 mM) and increases in cAMP produced by isoproterenol (10⁻⁴ M). It was also found that exposure of the rat uterus to a Ca++-deficient solution (Ca++-free with 0.2 mM EGTA) accentuated the Increase of tissue cAMP content produced by isoproterenol (10⁻⁸ M). The studies on ionic interactions demonstrated that the presence of Na+(80 mM) or high Mg++(2.5 mM) in the depolarizing medium could overcome the blockade of lsoproterenol-induced increases in cAMP levels by high-K+ depolarization. The studies on the mechanism of this effect of Na+ on the cAMP response revealed that Na+ exerted this effect probably by reducing the Increase In Ca++-influx occurring during depolarization. A similar type of interaction between Mg++ and Ca++ was also observed. These studies have pointed out a possible regulatory role of Ca++ in isoproterenol-lnduced Increases in cAMP levels in uterine smooth muscle. Since it was also demonstrated that cAMP Is not an obligatory requirement In order for Isoproterenol to produce relaxation, these data have raised the question as to whether the Increases ln cAMP produced by β-adrenoceptor stimulation Is an event secondary to the changes in Ca++ movements produced by the agonist. The electrophysiological studies showed that isoproterenol (10 M) could inhibit spontaneous contractility of the rat uterus without causing hyperpolarlzation. In hlgh-K+ depolarized muscle, Isoproterenol (10⁻⁶M) produced relaxation without any change in membrane potential. These data suggested that hyperpolarlzation of cell membranes is not a prerequisite for β-adrenoceptor-med-lated relaxation of uterine smooth muscle. / Pharmaceutical Sciences, Faculty of / Graduate

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Thesis (Ph.D. in Clinical Science) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 130-142). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

Le diabète prédispose à des complications affectant divers organes comme le systémecardiovasculaire. La cardiopathie ischémique chez les patients diabétiques pourrait être liée àl'accumulation de produits avancés de glycation (AGEs). Dans les coeurs de rats ischémiques,l'expression des récepteurs aux AGEs et de ses ligands est considérablement augmentée etimpliquée dans les lésions de l'ischémie / reperfusion (I / R), même en absence de diabète. Ila été récemment rapporté que le myocarde humain diabétique ne peut pas être protégé par lepréconditionnement. Dans ce contexte, notre hypothèse était que le préconditionnement β1-adrénergique pourrait être modifié en présence d'AGE. En utilisant un modèle de coeur isolénon travaillant de rat, cette étude a pour but d’étudier les effets des AGEs sur lacardioprotection induite par la stimulation des récepteurs β1-adrénergiques (β1-ARs) par lexamotérol (xa). Les effets bénéfiques induits par le xa pendant la reperfusion ont étésupprimés par l'administration de l’albumine glyquée (Alb-Gly) pendant la perfusion du xa,tandis que l’albumine (Alb) n’a pas modifié cette protection. Ces résultats suggèrent que lesAGEs suppriment la cardioprotection résultant de l'activation de la voie β1-AR ce quicontribue à des dommages cardio-vasculaires chez les patients diabétiques.D’ autre part, le pyridoxal 5’-phosphate (PLP), un métabolite naturel de la pyridoxine qui estun antagoniste des récepteurs purinergiques, empêche la surcharge cellulaire en calcium etpeut réduire les dommages d'ischémie-reperfusion. Plusieurs travaux ont mis en evidence unediminution des taux du PLP chez les patients souffrant d'un infarctus du myocarde par rapportà un groupe témoin sain. Plus récemment, il a été signalé qu’un taux bas de PLP confère unrisque indépendant de maladie coronaire. Cette corrélation de la réduction du PLP chez lespatients souffrant d’infarctus est soutenue par les effets préventifs de la vitamine B6 sur lesmaladies coronaires et le diabète. Plusieurs travaux ont montré que le PLP et la pyridoxaminepréviennent la progression de la néphropathie induite par la STZ chez les rats diabétiques eninhibant la formation des AGEs. En utilisant un modèle de coeur isolé non-travaillant de rat,cette étude a examiné les mécanismes de préconditionnement pharmacologique (PC) induitpar la stimulation des récepteurs P2Y par le pyridoxal-5'-phosphate (PLP). La suppression del'effet cardioprotecteur du PLP par le MRS2578, antagoniste des récepteurs P2Y6 et parl’U73122 qui bloque la phospholipase C est en accord avec l’implication du récepteur P2Y6dans le préconditionnement. La suppression de l'effet cardioprotecteur du PLP par l'AMPαS,antagoniste des récepteurs P2Y11, l’H89 inhibiteur de la PKA et par l’U73122 démontrel’implication aussi des récepteurs P2Y11 dans ce préconditionnement. L’exposition préischémique à des concentrations nanomolaires de PLP protège contre les lésions de l’ I / R.P2Y11 et P2Y6 représentent ainsi les récepteurs candidats les plus probables pour le PCcardiaque induit par le PLP. / Diabetes predisposes to complications affecting various organs such as cardiovascular system.Ischemic heart disease in diabetic patients might be linked to the accumulation ofadvanced-glycation end products (AGEs). In ischemic rat hearts, expression of receptor forAGEs and its ligands is significantly enhanced and involved in cardiac ischemia/reperfusion(I/R) injury even in the absence of diabetes. It has recently been reported that diabetic humanmyocardium cannot be protected by preconditioning. In this context, our hypothesis was thatβ1-adrenergic preconditioning might be altered in the presence of AGEs. Using an isolatednon-working rat heart model, this study investigated the effect of AGEs on cardioprotectioninduced by transient β1-adrenoceptor (β1-AR) stimulation with xamoterol (xa). The beneficialeffects induced by xa during reperfusion were suppressed by the administration of glycatedalbumin (Gly-Alb) during xa infusion, whereas albumin (Alb) did not hamper xa inducedprotection. These results suggest that AGEs suppress the cardioprotection resulting from theactivation of β1-ARs and thus might contribute to cardiovascular damages seen in diabeticpatients.Pyridoxal 5'-phosphate (PLP), a natural metabolite of pyridoxine which is an antagonist ofpurinergic receptors prevents cellular calcium overload and may reduce ischemia-reperfusioninjury. Low plasma pyridoxal-5′-phosphate levels have been observed in patients sufferingfrom myocardial infarction, when compared with a healthy control group. More recently, lowPLP level has been reported to confer an independent risk for coronary artery disease. Thefact that this correlation of PLP reduction in infarct patients has functional importance issupported by the preventive effects of vitamin B6 on coronary heart disease and diabetes. PLPprevented progression of nephropathy in STZ-induced diabetic rats by inhibiting formation ofAGEs. Using an isolated non-working rat heart model, this study investigated the mechanismsof pharmacological pre-conditioning (PC) induced by P2Y receptor stimulation withpyridoxal-5’-phosphate (PLP). The suppression of the cardioprotective effects of PLP byMRS2578 and U73122 is in agreement with the P2Y6 receptor as a receptor for PLP-inducedPC.The suppression of the cardioprotective effects of PLP by AMPαS, the PKA inhibitor (H89),and (U73122) is in agreement with the P2Y11 receptor as a receptor for PLP-induced PC.Pre-ischemic exposure to nanomolar concentrations of PLP is protective against I/R. P2Y11and P2Y6 represent the most likely candidate receptors for PLP-induced cardiac PC.

by Shan Sze Wan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 145-166). / Abstracts in English and Chinese. / Title --- p.i / Abstract --- p.ii / 摘要 --- p.v / Acknowledgements --- p.vii / Table of Contents --- p.viii / List of Abbreviations --- p.xiv / List of Figures --- p.xvii / List of Tables --- p.xx / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- What are the general functions of cytokines? --- p.2 / Chapter 1.2 --- What is TNP-α? --- p.4 / Chapter 1.3 --- Actions of TNF-α --- p.5 / Chapter 1.4 --- General functions of TNF-α in astrocytes --- p.6 / Chapter 1.5 --- TNF-α receptors (TNF-Rs) --- p.8 / Chapter 1.6 --- Second messengers induced by TNP-α --- p.10 / Chapter 1.7 --- Glial Cells --- p.11 / Chapter 1.7.1 --- Oligodendroglia --- p.12 / Chapter 1.7.2 --- Brain Macrophages (Microglia) --- p.12 / Chapter 1.7.3 --- Astrocytes --- p.14 / Chapter 1.7.3.1 --- Functions of astrocytes --- p.15 / Chapter 1.8 --- "Brain injury, astrogliosis and scar formation" --- p.20 / Chapter 1.9 --- β-Adrenergic receptors (β-ARs) --- p.21 / Chapter 1.9.1 --- The active functional unit: the receptor complex --- p.22 / Chapter 1.9.2 --- General functions and distribution of β-ARs --- p.22 / Chapter 1.10 --- Functions of β-ARs in astrocytes --- p.24 / Chapter 1.10.1 --- Regulations of astrogliosis by β-ARs --- p.24 / Chapter 1.10.1.1 --- β-ARs are expressed in normal optic nerves and up-regulated after nerve crush --- p.24 / Chapter 1.10.1.2 --- Injury-induced alterations in endogenous catecholamine leads to enhanced β-AR activation --- p.25 / Chapter 1.10.1.3 --- β-AR blockade suppresses glial scar formation --- p.25 / Chapter 1.10.1.4 --- β-AR agonists affect the proliferation of astrocytes in normal brain --- p.26 / Chapter 1.11 --- Manganese Superoxide Dismutase (MnSOD) --- p.27 / Chapter 1.11.1 --- MnSOD is the target gene of NF-kB --- p.29 / Chapter 1.11.2 --- Induction of MnSOD by proinflammatory cytokines in rat primary astrocytes --- p.29 / Chapter 1.11.3 --- SMase and ceramides induce MnSOD in various cell types --- p.30 / Chapter 1.12 --- Why do we use C6 glioma cells? --- p.31 / Chapter 1.13 --- Aims and Scopes of this project --- p.32 / Chapter Chapter 2 --- MATERIALS AND METHODS / Chapter 2.1 --- Materials --- p.36 / Chapter 2.1.1 --- Cell Line --- p.36 / Chapter 2.1.2 --- Cell Culture Reagents --- p.36 / Chapter 2.1.2.1 --- Complete Dulbecco´ةs modified Eagle medium (CDMEM) --- p.36 / Chapter 2.1.2.2 --- Rosewell Park Memorial Institute (RPMI) medium --- p.37 / Chapter 2.1.2.3 --- Phosphate buffered saline (PBS) --- p.37 / Chapter 2.1.3 --- Recombinant cytokines --- p.38 / Chapter 2.1.4 --- Chemicals for signal transduction study --- p.38 / Chapter 2.1.4.1 --- Modulators of protein kinase C (PKC) --- p.38 / Chapter 2.1.4.2 --- Modulator of protein kinase A (PKA) --- p.39 / Chapter 2.1.4.3 --- β-Adrenergic agonist and antagonist --- p.39 / Chapter 2.1.5 --- Antibodies --- p.40 / Chapter 2.1.5.1 --- Anti-TNF-receptor type 1 (TNF-R1) antibody --- p.40 / Chapter 2.1.5.2 --- Anti-TNF-receptor type 2 (TNF-R2) antibody --- p.41 / Chapter 2.1.5.3 --- Anti-βi-adrenergic receptor (βl-AR) antibody --- p.42 / Chapter 2.1.5.4 --- Anti-β2-adrenergic receptor (β2-AR) antibody --- p.42 / Chapter 2.1.5.5 --- Antibody conjugates --- p.43 / Chapter 2.1.6 --- Reagents for RNA isolation --- p.43 / Chapter 2.1.7 --- Reagents for reverse transcription-polymerase chain reaction (RT-PCR) --- p.43 / Chapter 2.1.8 --- Reagents for electrophoresis --- p.45 / Chapter 2.1.9 --- Reagents and buffers for Western blot --- p.45 / Chapter 2.1.10 --- Other chemicals and reagents --- p.47 / Chapter 2.2 --- Maintenance of rat C6 glioma cell line --- p.47 / Chapter 2.3 --- RNA isolation --- p.48 / Chapter 2.3.1 --- Measurement of RNA yield --- p.49 / Chapter 2.4 --- Reverse transcription-polymerase chain reaction (RT-PCR) --- p.50 / Chapter 2.5 --- Western blot analysis --- p.52 / Chapter Chapter 3 --- RESULTS / Chapter 3.1 --- Effect of TNF-α on the expression of TNF-receptors (TNFRs) in C6 glioma cells --- p.55 / Chapter 3.1.1 --- Effect of TNF-α on TNF-R1 and -R2 mRNA expression in C6 cells --- p.56 / Chapter 3.1.2 --- The signaling systems mediating TNP-α-induced TNF-R2 expression in C6 cells --- p.57 / Chapter 3.1.2.1 --- The involvement of PKC in TNF-α-induced TNF-R2 expression in C6 cells --- p.57 / Chapter 3.1.2.2 --- Effect of PMA on the TNF-R protein levels in C6 cells --- p.63 / Chapter 3.1.2.3 --- Effect of Ro31 on the TNF-α-induced TNF-R protein level in C6 cells --- p.65 / Chapter 3.1.2.4 --- Effect of PKA activator on the level of TNF-R2 mRNA in C6 cells --- p.67 / Chapter 3.2 --- Effect of TNP-α on the expression of β1- and β2-adrenergic receptors (β1- and β2-ARs) in C6 glioma cells --- p.69 / Chapter 3.2.1 --- Effect of TNF-α on β1- and β2-ARs mRNA expression in C6 cells --- p.70 / Chapter 3.2.2 --- The signaling systems mediating TNF-α-induced β1- and β2-AR expression in C6 cells --- p.70 / Chapter 3.2.2.1 --- The involvement of PKC mechanism between TNF-α and β-ARs in C6 cells --- p.71 / Chapter 3.2.2.2 --- Effect of PMA on the β1- and β2-ARs protein level in C6 cells --- p.76 / Chapter 3.2.2.3 --- Effect of Ro31 on the TNF-α-induced β1- and β2-AR protein levels in C6 cells --- p.78 / Chapter 3.2.2.4 --- Effect of dbcAMP on the levels of βl- and β2-ARs mRNA in C6 cells --- p.80 / Chapter 3.3 --- Relationship between TN1F-R2 and β-adrenergic mechanism in C6 cells --- p.82 / Chapter 3.3.1 --- Effects of isproterenol and propranolol on endogenous TNF-α mRNA levels in C6 cells --- p.82 / Chapter 3.3.2 --- Effects of isoproterenol and propranolol on TNF-R2 mRNA levels in C6 cells --- p.83 / Chapter 3.3.3 --- Effects of β1-agonist and antagonist on endogenous TNF-α mRNA expression in C6 cells --- p.87 / Chapter 3.3.4 --- Effects of β1-agonist and antagonist on TNF-R2 mRNA expression in C6 cells --- p.91 / Chapter 3.3.5 --- Effects of β2-agonist and antagonist on endogenous TNF-α mRNA in C6 cells --- p.93 / Chapter 3.3.6 --- Effects of β2-agonist and antagonist on TNF-R2 mRNA in C6 cells --- p.100 / Chapter 3.4 --- Effect ofTNF-α on the expression of a transcriptional factor nuclear factor kappa B (NF-kB) in C6 glioma cells --- p.102 / Chapter 3.4.1 --- Effect ofTNF-α on NF-kB (p50) mRNA expression in C6 cells --- p.106 / Chapter 3.4.2 --- Effect of β-agonist and antagonist on NF-kB (p50) mRNA expression in C6 cells --- p.108 / Chapter 3.4.3 --- Effect of PMA and Ro31 on the levels of NF-kB mRNA in C6 cells --- p.109 / Chapter 3.5 --- Effects of TNF-α on the expression of manganese superoxide dismutase (MnSOD) in C6 glioma cells --- p.111 / Chapter 3.5.1 --- Effects of TNF-α on MnSOD and Cu-ZnSOD mRNAs expression in C6 cells --- p.114 / Chapter 3.5.2 --- Effects of β-agonist and β-antagonist on MnSOD mRNA expression in C6 cells --- p.115 / Chapter 3.5.3 --- Effects of PKC activator and inhibitor on the levels of MnSOD mRNA in C6 cells --- p.117 / Chapter Chapter 4 --- DISCUSSION AND CONCLUSION / Chapter 4.1 --- Effects of TNF-α on the expression of TNF-receptors (TNFRs) in C6 glioma cells --- p.122 / Chapter 4.2 --- Effects of TNF-a on the expression of β1- and β2-adrenergic receptors (β1 and β2-ARs) in C6 glioma cells --- p.126 / Chapter 4.3 --- Relationship between TNF-α and β-adrenergic mechanism in C6 cells --- p.128 / Chapter 4.4 --- Effects of TNF-α on the expression of a transcriptional factor nuclear factor kappa B (NF-kB) in C6 glioma cells --- p.131 / Chapter 4.5 --- Effects of TNF-α on the expression of manganese superoxide dismutase (MnSOD) in C6 glioma cells --- p.133 / Chapter 4.6 --- Possible sources of β-agonists --- p.136 / Chapter 4.7 --- Conclusions --- p.137 / Appendix A --- p.143 / References --- p.145

Neonatal ventral hippocampus (nVH) lesioned animals show molecular and behavioral abnormalities analogous to those described in schizophrenia. As an extension to previous studies that showed an increase in ligand binding of cortical alpha-1 adrenergic receptors (AR) and a dysfunction in alpha-1 AR regulation of mesolimbic dopamine functions in post-pubertal nVH lesioned rats, we investigated the subcellular expression and activity of protein kinase C (PKC)---a second messenger in alpha-1 AR signaling---in the prefrontal cortex (PFC) and nucleus accumbens (NAcc) of post-pubertal nVH lesioned rats. Western blot analysis of membrane and cytosolic fractions showed complex changes in lesioned animals in the expression of different PKC subtypes following saline or alpha-1 AR agonist (cirazoline i.p.) injection. Among these changes, nVH lesioned animals showed a significant increase in membrane bound PKC alpha and phospho-PKC, and a decrease in cytosolic PKC gamma and PKC betaII in the PFC in comparison to sham-lesioned controls following saline. Cirazoline increased membrane bound PKC alpha in controls but decreased it in lesioned animals. In the NAcc, lesioned animals showed an increase in membrane bound and cytosolic PKC epsilon and PKC lambda levels following saline. Following cirazoline, lesioned animals showed a decrease in membrane bound PKC epsilon and PKC lambda, while controls showed an increase in cytosolic and membrane fractions of PKC epsilon with no change in PKC lambda. In vitro PKC activity assays showed increased basal activity in PFC slices of lesioned animals compared to controls, with no difference in NAcc slices. alpha-1 AR stimulation by the agonist phenylephrine (PE) increased PKC activity in PFC of controls while decreasing activity substantially in lesioned animals. In the NAcc, high concentrations of PE increased activity in controls, but decreased activity in lesioned animals. This abnormal expression and activity of PKC in the PFC and NAcc of nVH lesioned animals may be related to abnormal alpha-1 AR functions and may modulate some of the abnormal neuronal functions in these animals, such as working memory deficits and hyper neuronal excitability of the PFC and the NAcc.

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.