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The present review focuses on the roles of thromboxane A2 (TxA2) in arterial thrombosis, atherogenesis, vascular stent-related ischemic events and renal proteinuria. Particular emphasis is laid on therapeutic interventions targeting the TxA2 (TP) receptors and TxA2 synthase (TS), including dual TP-receptor antagonists and TS inhibitors. Their significant inhibitory efficacies on arterial thrombogenesis, atherogenesis, restenosis after stent placement, vasoconstriction and proteinuria indicate novel and improved treatments for cardiovascular and selected renal diseases. New therapeutic interventions of the TxA2 pathway may also be beneficial for patients with poor biological antiplatelet drug response, for example, to aspirin and/or clopidogrel. These new TP/TS agents offer novel improved treatments to efficiently and simultaneously interfere with thrombogenesis and atherogenesis, and to enlarge the existing panel of platelet inhibitors for efficient prophylaxis and treatment of arterial thrombosis and renal proteinuria.

11 beta-Hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) has been proposed as a new target for type 2 diabetes drugs. The aim of the present study was to assess the effects of inhibition of 11 beta-HSD1 on blood glucose levels, glucose tolerance, and insulin sensitivity in mouse models of type 2 diabetes. BVT.2733 is an isoform-selective inhibitor of mouse 11 beta-HSD1. Hyperglycemic and hyperinsulinemic ob/ob, db/db, KKAy, and normal C57BL/6J mice were orally administered BVT.2733 (200 mg/kg.d, twice daily). In hyperglycemic, but not in normal mice, BVT.2733 lowered circulating glucose (to 50-88% of control) and insulin (52-65%) levels. In oral glucose tolerance tests in ob/ob and KKAy mice, glucose concentrations were 65-75% of vehicle values after BVT.2733 treatment, and in KKAy mice insulin concentrations were decreased (62-74%). Euglycemic, hyperinsulinemic clamps demonstrated decreased endogenous glucose production (21-61%). Analysis of hepatic mRNA in KKAy mice showed reduced phosphoenolpyruvate carboxykinase mRNA (71%). A slight reduction in food intake was observed in ob/ob and KKAy mice. Cholesterol, triglycerides, and free fatty acid levels were decreased to 81-86% in KKAy mice after a 4-h fast. The results support previous suggestions that selective 11 beta-HSD1 inhibitors lower blood glucose levels and improve insulin sensitivity in different mouse models of type 2 diabetes.

Stress incontinence and overactive bladder are disorders with a common symptom, urinary incontinence, which is a serious medical and social handicap. Several neurotransmitters regulate the function of the lower urinary tract, including noradrenaline, acetylcholine, and serotonin.The present study is part of the search for pharmacological incontinence drugs. The aims of this thesis were to improve the existing pharmacological treatments of urinary incontinence and to look for alternative treatments: i) an α1-adrenergic agonist that preferentially affects urethral over blood pressure was tested in vivo; ii) a modified cystometry model was developed for screening of muscarinic antagonists, by construction of a complete dose-response curve in each individual animal; iii) a new muscarinic antagonist, PNU-171990, was pharmacologically characterized in vitro and in vivo; iv) functional differences of the isomers of the muscarinic agonist BM-5 were characterized in the urinary bladder and ileum, in vitro and in vivo; v) the role of serotonin 5-HT2A, 5-HT3 and 5-HT4 receptors were characterized on urinary bladder contractions in vivo.In the search for urethra selective compounds, the α1-adrenoceptors agonists phenylephrine and phenylpropanolamine selectively enhanced blood pressure as compared to the urethral pressure in rabbit. This is in contrast to the effect of oxymetazoline and NS-49. Muscarinic antagonists produced a dose-dependent inhibition of the volume-induced micturition pressure in the rat. PNU-171990, a non-selective muscarinic antagonist, revealed selectivity for urinary bladder pressure over salivation (P

Objective The aim of this study was to investigate the distribution of alpha1- and alpha2-adrenoceptors in the urethra and urinary bladder of the female pig, cat, guinea-pig and rat. Materials and methods The binding distributions of an alpha1-adrenoceptor ligand (3H-prazosin) and an alpha2-adrenoceptor ligand (3H-rauwolscine) were determined using in vitro autoradiography. Autoradiograms were analysed by combining computer-based image analysis and light microscopy. Results In the pig, guinea-pig and rat urethra 3H-prazosin binding was highest in the muscle layer. In the cat urethra 3H-prazosin binding could not be analysed due to a negative chemography artefact. In the pig, cat and guinea-pig urethra 3H-rauwolscine binding was highest in the urothelium, followed by the sub-mucosa, with low levels in muscle. Little 3H-rauwolscine binding was observed in the rat urethra. In the urinary bladder of all species 3H-prazosin binding was low. In the rat bladder, binding was higher in the trigone than in the dome. In the pig, cat and guinea-pig bladder 3H-rauwolscine binding was highest in the mucosa. with little binding in muscle or lamina propria. In the rat bladder, there was little binding and no regional differences. Conclusions Alpha1-adrenoceptors were predominantly located in urethral smooth muscle, indicating their contractile importance in maintaining continence. Alpha2-Adrenoceptors were present in the urethral submucosa and bladder mucosa, but not in muscle, suggesting a role in regulation of blood flow, urethral lubrication and tumescence, but not in contraction.

Pancreatic β-cells sense the concentration of glucose in the systemic circulation through metabolism of the sugar molecule. Failure to correlate the blood sugar concentration to an appropriate metabolic signal disrupts the function of the β-cell as a controller of glucose homeostasis and may contribute to the development of type 2 diabetes mellitus. Release of insulin is pulsatile and this thesis presents data that support that metabolism drives such pulsatile release. It is also found that increase in insulin release in response to elevation of the glucose concentration is only seen when the rise in glucose induces a prompt and sustained increase in mitochondrial metabolism. Such activation of mitochondrial metabolism depended on the metabolic state of the β-cell prior to the glucose challenge. In this context, prolonged periods of elevated levels of fatty acids are harmful to the pancreatic β-cell. To study the protein expression changes induced by fatty acids a protocol for islet protein profiling and identification of differently expressed proteins were developed. By using this protocol it was discovered that oleate decreased the cellular level of the chaperone peptidyl-prolyl isomerase B. The protocol was also used to study protein expression in islets obtained from mice fed a high-fat and/or a high-sucrose diet. Excess of glucocorticoids in the systemic circulation also cause a diabetic phenotype. Tissue response to glucocorticoids is regulated by the intracellular concentration of the active form of glucocorticoids, which is formed from the inactive form by the enzyme 11β-hydroxysteroid dehydrogenase type 1. It was found that pancreatic islets produce 11β-HSD1 protein in relation to substrate availability and that the amount of islet 11β-HSD1 protein was negatively correlated with insulin secretion.

The present study was done to characterize a new compound, PNU-171990, 2-diisopropyl aminoethyl 1-phenylcyclopentane carboxylate hydrochloride, with functional smooth muscle selectivity at least as high as tolterodine. In vitro homogenates of guinea pig cerebral cortex, parotid gland, heart, urinary bladder, and Chinese hamster ovary (CHO) cells expressing human muscarinic m(1)-m(5) receptors PNU-171990 did not show selectivity for any subtype (pK(i), 7.72-8.64). PNU-171990 caused a parallel shift in the concentration-response curve for carbachol-induced contraction of smooth muscle from guinea pig bladder (pK(B), 7.65), guinea pig ileum (pK(B), 8.48), and human ileum (pK(B), 7.10). In vivo PNU-171990 inhibited urinary bladder contraction with a significantly lower ID(50) than on the salivary secretion (206 and 706 nmol/kg, respectively, P0.05). In conclusion, PNU-171990 is a competitive and potent muscarinic receptor antagonist in vitro with a numerically better selectivity ratio for the bladder contraction over salivation in vivo than tolterodine.

Novel antidiabetic arylsulfonamidothiazoles are presented that exert action through selective inhibition of the 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) enzyme, thereby attenuating hepatic gluconeogenesis. The diethylamide derivative 2a was shown to potently inhibit human 11beta-HSD1 (IC(50) = 52 nM), whereas the N-methylpiperazinamide analogue 2b only inhibited murine 11beta-HSD1 (IC(50) = 96 nM). Both compounds showed >200-fold selectivity over human and murine 11beta-HSD2. 2b was subsequently shown to reduce glucose levels in diabetic KKA(y) mice, substantiating the 11beta-HSD1 enzyme as a target for the treatment of type 2 diabetes.

The guinea-pig ileum longitudinal muscle-myenteric plexus preparation, pre-incubated with [3H]choline, was mounted in an organ bath and superfused with Tyrode's solution. [3H]Acetylcholine secretion was evoked by 150 electrical shocks at 0.5 Hz. >N6,2′-0-Dibutyryladenosine 3′,5′-cyclic monophosphate (dibutyryl cyclic AMP) enhanced the [3H]acetylcholine secretion in the presence of eserine and the adenosine receptor antagonist 8-phenyltheophylline (10 μmol 1-1). Conversely, in the absence of 8-phenyltheophylline the [3H]acetylcholine secretion was reduced by dibutyryl cyclic AMP. In the absence and presence of 8-phenyltheophylline (apparent KD = 12 μ.mol 1-1), adenosine reduced the [3H]acetylcholine secretion to 33% of control (IC50 = 8, μmol l-1) and to 48% of control (IC50 = 14 μmol l-1) respectively. Neither butyrate, dibutyryl cyclic GMP nor guanosine altered the [3H]acetylcholine secretion. Interaction experiments with 3-isobutyl-1-methylxanthine and oxotremorine were done in the absence of eserine, i.e. when oxotremorine is effective. Oxotremorine depressed the fractional secretion of [3H]acetylcholine with a ‘maximal inhibition’ of 13% of control (IC50 = 10 nmol l-1). In the presence of 3-isobutyl-1-methylxanthine (5 mmol l-1) oxotremorine depressed the secretion to 2% of control with an apparent IC50) value of 0.9 μmol l-1 3-Isobutyl-I-methylxanthine (0.01–4 mmol l-1) enhanced the fractional secretion of [3H]acetylcholine with a ‘maximal enhancement’ value of 232% of control (EC50 = 0.19 mmol l-1). The presence of oxotremorine (30 nmol l-1) counteracted, and higher concentrations reversed, the enhancement caused by 3–isobutyl-I-methylxanthine. The results are consistent with the suggestion that the presynaptic muscarinic acetylcholine receptor-mediated control of the secretion of [3H]acetylcholine in the guinea-pig ileum myenteric plexus may be mediated both by cyclic AMP and calcium ions.

Secretion of 3H-noradrenaline was evoked by electrical field stimulation (1 Hz, 300 shocks) in guinea-pig ileum myenteric plexus. The role of cyclic nucleotides in the presynaptic receptor-mediated control of 3H-noradrenaline secretion was studied. The secretion of 3H-noradrenaline was maximally enhanced to the same extent, viz. 300-400% of control, by two analogues of cyclic AMP (8-Br cyclic AMP and dibutyryl cyclic AMP), by an adenylate cyclase activator (forskolin) and by three structurally different inhibitors of phosphodiesterase (3-isobutyl-1-methylxanthine, SQ 20,006 and Ro 20-1724), but not altered by two analogues of cyclic GMP (8-Br cyclic GMP and dibutyryl cyclic GMP). Added separately an alpha 2-adrenoceptor antagonist (yohimbine) and a beta-adrenoceptor agonist (isoprenaline) enhanced the 3H-noradrenaline secretion. Yohimbine, but not isoprenaline, increased additively the 'maximal enhancement' of the 3H-noradrenaline secretion caused by 3-isobutyl-1-methylxanthine. These results suggest that neuronal cyclic AMP may be involved in beta- but not in alpha-adrenoceptor-mediated control of 3H-noradrenaline secretion in guinea-pig ileum myenteric nerve terminals.

Acetylcholine (ACh) secretion from guinea-pig ileum myenteric plexus is affected by muscarinic agents (1, 4, 5, 6, 9, 11). The secretion is also influenced by inhibitors of phosphodiesterase (3, 10, 12). Addition of 8-Br cyclic AMP enhanced the secretion of [3H]-ACh from guinea-pig ileum myenteric plexus, while the 8-Br analog of cyclic GMP was without effect (2).