Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.4.1 (phosphodiesterase)
18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cilostazol is a selective orally active phosphodiesterase (PDE) III inhibitor. This study was conducted to evaluate whether inhibition of PDE subtype III can reduce bronchial responsiveness. We examined the effects of cilostazol on bronchial responsiveness to methacholine in eight normal subjects by a single-blinded, crossover study. Each subject received 200 mg of cilostazol or placebo in random order. The subjects underwent methacholine challenge test 3 h after administration of each drug on two occasions separated by 5 d or more. The geometric mean value of provocative concentration of methacholine causing a 20% fall in FEV1 (PC20-FEV1) and the mean value (+/- SEM) of maximum expiratory flow on partial flow-volume curve at isovolume of 40% FVC above residual volume (PEF40) after administration of cilostazol were 25.3 (geometric standard error of the mean [GSEM], 1.35) mg/ml and 3.78 +/- 0.31 L/s, which were significantly (p < 0.02 and p < 0.05) greater than those after the placebo administration (6.81 [GSEM, 1.42] mg/ml and 2.71 +/- 0.39 L/s). All subjects complained of mild to severe headache when cilostazol was given. These findings suggest that PDE III inhibitors such as cilostazol have bronchodilator and bronchoprotective effects in humans. Further studies regarding smaller oral dosing of or aerosol administration of cilostazol or the other PDE III inhibitors are needed to determine clinical usefulness.
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PMID:Bronchodilator and bronchoprotective effects of cilostazol in humans in vivo. 781 59

Adenosine causes airway obstruction in asthmatics and smokers. Theophylline and cromolyn, drugs used to treat these patients, bind to human lung adenosine receptors (ARs). This study investigated whether A1ARs and/or A2ARs are functionally present in human lung and airways, and whether theophylline and/or cromolyn antagonize their function. Peripheral lung or airway fragments from 21 people were incubated for 15 min with (1) an A1AR agonist, N6-cyclopentyladenosine (CPA, 5 to 1,000 nM), or (2) an A2AR agonist, either 5'-N-ethylcarboxamido adenosine (NECA, 0.5 to 20 microM) or 2-[p-(2-carboxyethyl)-phenethyl amino]-5'-N-ethylcarboxamido adenosine (CGS 21680, 0.5 to 28 microM), in the presence of the A1AR antagonist 8-cyclopentyl-1,3-dipropylxanthine (50 nM) and/or (3) theophylline (1 mM) and/or (4) cromolyn (500 microM). Adenosine deaminase (2 U/ml) and the phosphodiesterase inhibitor Ro 20-1724 (2 mM) were present in all incubations. Cyclic adenosine monophosphate (cAMP) was measured by radioimmunoassay. In peripheral lung, CPA did not change baseline or isoproterenol-stimulated cAMP content. However, both NECA (20 microM) and CGS 21680 (28 microM) significantly (P < 0.05) increased cAMP content 220 +/- 4% and 201 +/- 32%, respectively (mean +/- SEM). In airways, 20 microM NECA increased cAMP content 129 +/- 34%, and 28 microM CGS 21680 increased it 52 +/- 20% (both P < 0.05). In both peripheral lung and airway tissue, NECA-induced increase in cAMP was antagonized by theophylline (P < 0.05) but not cromolyn. The lungs of younger, nonsmokers had lower baseline cAMP content but did not respond differentially to A2AR stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of adenosine receptor ligands on cAMP content in human airways and peripheral lung. 839 27

In the present study, we investigated if the relaxant effects of phosphodiesterase (PDE) III inhibitors on human vessels could be inhibited by a nitric oxide synthase blocker, L-NAME, or by a blocker of ATP-sensitive potassium channels (KATP), glibenclamide. The experiments were performed using an isometric myograph in isolated human s.c. small arteries obtained from healthy donors. After a priming procedure consisting of exposure to high potassium (120 mmol litre-1) solutions, phenylephrine 10 mumol litre-1 and an equilibrium period of 30 min, the preparations were contracted with a thromboxane A2 mimetic agent, U46619 1 mumol litre-1. Subsequently, cumulative concentration-response curves were constructed for the selective PDE III inhibitors amrinone, milrinone and enoximone, and for theophylline and dipyridamole, with and without the addition of L-NAME 100 mumol litre-1 or glibenclamide 1 mumol litre-1. Addition of L-NAME to the organ bath resulted in significantly higher pEC50 values (-log of the concentration required for 50% relaxation) for milrinone compared with the control: 2.77 (SEM 0.24) mol litre-1 (n = 5) vs 3.49 (0.17) mol litre-1 (n = 7) (P < 0.05). There was no significant difference between any other group. From our data we conclude that the relaxant properties of amrinone, enoximone, theophylline and dipyridamole are not dependent on nitric oxide release or on interaction with KATP channels. However, the effect of milrinone may be partly endothelium-dependent in human vessels in vitro.
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PMID:Effect of phosphodiesterase inhibitors on human arteries in vitro. 867 53

Nanterinone (UK-61,260) is a novel positive inotropic and balanced-type vasodilating drug, only partially based on phosphodiesterase III inhibition. Preliminary data from controlled studies suggest satisfactory long-term efficacy and safety. As its acute hemodynamic effects in humans are unknown, an oral dose of 2 mg nanterinone was studied in 14 patients with heart failure (NYHA class II-III) on chronic diuretic and angiotensin-converting enzyme (ACE) inhibitor treatment. Before the study, patients were on a 2 g salt-balanced diet, and they received their last medication 16 hours before each study day. Hemodynamic measurements were carried out before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 8, 12, and 24 hours after administration of the study drug. All patients received placebo and nanterinone on 2 consecutive days. Following nanterinone, systemic vascular resistance decreased immediately from 1699 +/- 82 (mean +/- SEM) at baseline to 1368 +/- 80 at 1 hour. Changes persisted for 12 hours. Concomitantly, there was an immediate and significant fall in pulmonary wedge pressure to 38% of baseline at 1.5 hours, together with a 20% reduction in pulmonary artery pressure. Heart rate remained unchanged and arterial pressures showed only a short, significant decrease. Cardiac index rose significantly from 2.28 +/- 0.15 at baseline to a highest value of 2.65 +/- 0.14 1/min/m2 at 1 hour. Changes persisted for 3 hours. Placebo had no effect on these variables. As, in view of its potential venodilating properties, hemodynamic improvement by nanterinone may depend on pre-existing left ventricular filling pressure, patients were subsequently grouped according to baseline pulmonary wedge pressure of > 12 mmHg (H-PCWP) and < or = 12 mmHg (L-PCWP). Cardiac index improved by 26% in H-PCWP and by 17% in L-PCWP (NS). In contrast, PCWP fell more markedly in H-PWCP than in L-PCWP (40% and 23%, respectively, p < 0.05). Thus, oral nanterinone results in a significant acute hemodynamic improvement and is well tolerated. Although changes in left ventricular filling pressure are more pronounced in patients with elevated pre-existing PCWP, cardiac pump function improves equally in patients with normal or low left ventricular filling pressure at baseline.
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PMID:Acute hemodynamic effects and preload-dependent cardiovascular profile of the partial phosphodiesterase inhibitor nanterinone in patients with mild to moderate heart failure. 884 5

In confirmation of a previous study (Am J Hypertens 1993;6:723), mean arterial blood pressure (MBP), as determined by tail cuff plethysmography, was found to be significantly elevated in Sprague-Dawley rats after 3 months of feeding 0.48 mmol/L (100 ppm) lead acetate/day (144 +/- 3.3 [SEM], in lead-treated [L] v 107 +/- 3.3 mm Hg in controls [C], P < .001). Thoracic aorta was excised from L and C animals (n = 6). Segments were suspended in tissue baths with Krebs' bicarbonate solution, then tested sequentially for vasoreactivity to 68 mmol/L K+, followed by graded concentrations of phenylephrine (PE), 0.01 to 0.3 micromol/L, acetylcholine (Ach), 0.001 to 3 micromol/L, nitroprusside (SNP), 0.0001 to 0.1 micromol/L, norepinephrine (NE), 0.001 to 300 micromol/L. There were no differences between L and C animals with respect to either vasoconstrictors (PE and NE) or vasodilators (Ach and SNP). The tissue levels of cGMP measured with and without phosphodiesterase inhibition, and in the absence and presence of either Ach or SNP, were comparable in the two groups. We conclude that the intrinsic vascular responsiveness is unchanged in lead-treated animals. The elevation of MBP is due to the presence of circulating factor(s) and hemodynamic changes.
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PMID:Lead-induced hypertension is not associated with altered vascular reactivity in vitro. 932 5

To elucidate the mechanism of relaxin action, we studied the binding characteristics of human relaxin and its effects on intracellular concentrations of cAMP and tyrosine phosphorylation of cellular proteins in a model system of human cervix, human lower uterine segment fibroblasts. Human relaxin labeled with 125I bound specifically to a single class of high-affinity relaxin binding sites, distinct from insulin receptors, with a mean (+/-SEM) dissociation constant (Kd) of 4.36 +/- 1.7 x 10(-9) M and a mean of 3220 +/- 557 binding sites per cell in human lower uterine segment fibroblasts. Relaxin, in quantities that were shown previously to stimulate intracellular levels of cAMP in other cell types, had no effect on intracellular levels of cAMP in human lower uterine segment fibroblasts even in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine (IBMX). Incubation of the cells with relaxin caused a significant increase in tyrosine phosphorylation of a protein with an apparent Mr of approximately 220 kDa in these cells. In concert with results of recent studies that demonstrated that the Mr of the relaxin receptor is approximately 220 kDa, our data suggest that the phosphorylated protein is likely to be the relaxin receptor.
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PMID:Demonstration of a relaxin receptor and relaxin-stimulated tyrosine phosphorylation in human lower uterine segment fibroblasts. 949 55

Protein tyrosine kinase activity, leading to tyrosine phosphorylation of the intracellular domains of receptors or non-receptor proteins, is an important feature of downstream signalling after receptor binding of a variety factors, such as growth factors and cytokines. Since several members of these classes of paracrine-autocrine mediator may be involved in the intraovarian events of ovulation, the present study was designed to evaluate the effect of protein tyrosine kinase inhibition on the in vitro perfused rat ovary. Immature rats were primed with 20 iu pregnant mares' serum gonadotrophin 48 h before surgical isolation of the right ovary with connecting vasculature. The ovary was placed in a perfusion system for either 10 h, to examine ovarian concentrations of the established ovulatory mediators plasminogen activator, prostaglandins E2 and F2 alpha, or for 20 h, enabling a complete ovulatory process to occur in vitro. Ovulation was induced by ovine LH (0.2 microgram ml-1) in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (0.2 mmol l-1) and the effects of two different protein tyrosine kinase inhibitors, genistein and tyrphostin A25, were studied. Unstimulated control ovaries did not ovulate and showed low secretion of progesterone and oestradiol. Addition of LH + 3-isobutyl-1-methylxanthine resulted in a marked stimulation of steroid release, and ovulations occurred in all ovaries (9.0 +/- 0.9; mean +/- SEM). The protein tyrosine kinase inhibitors, genistein and tyrphostin A25, significantly inhibited ovulation at the higher concentrations tested (3.0 +/- 0.3 at 100 mumol genistein l-1; 5.8 +/- 1.0 at 500 mumol tyrphostin A25 l-1) but no effect was seen at lower concentrations. The presence of genistein and tyrphostin A25 at any concentration used did not significantly decrease the LH + 3-isobutyl-1-methylxanthine-induced progesterone or oestradiol concentrations. The intraovarian concentrations of plasminogen activator activity, and prostaglandin E2 and F2 alpha were not altered by the presence genistein (100 mumol l-1). In conclusion, the results of the present study indicate that protein tyrosine kinase signalling pathways are integral parts of the mammalian ovulatory process but do not involve actions on the synthesis of steroids, plasminogen activator or prostaglandins.
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PMID:Inhibition of ovulation by tyrosine kinase inhibitors in the in vitro perfused rat ovary. 1069 Feb 6

There is abundant evidence for T-lymphocyte recruitment into the airways in allergic inflammatory responses. This study has tested the hypothesis that T-cell chemotaxis induced by platelet-activating factor (PAF) and human recombinant interleukin-8 (hrIL-8) can be attenuated by inhibition of phosphodiesterase activity and raised intracellular 3',5'-cyclic adenosine monophosphate (cAMP) levels. This study used theophylline, a nonselective phosphodiesterase (PDE) inhibitor, and rolipram, a selective PDE4 inhibitor, to study the effect of PDE inhibition on T-cell chemotaxis. The beta2-adrenoceptor agonist, salbutamol, the adenylyl cyclase activator, forskolin, and the cAMP analogue, dibutyryl cAMP (db-cAMP), were used to demonstrate a role for raised cAMP levels. T-cells were obtained from 10 atopic asthmatics, and the phenotype of migrating cells was examined by flow cytometry. Theophylline caused an inhibition of both PAF-and hrIL-8-induced chemotaxis (mean+/-SEM maximum inhibition at 1 mM: 73+/-4% and 48+/-8% for hrIL-8 and PAF, respectively) that was not specific for the CD4+, CD8+, CD45RO+ or CD45RA+ T-cell subsets. T-cell chemotaxis was more sensitive to treatment with rolipram whose effect was already significant from 0.1 microM on hrIL-8-induced chemotaxis. Both a low concentration of salbutamol (0.1 mM) and forskolin (10 microM) potentiated the inhibitory effect of a low concentration of theophylline (25 microM) on responses to PAF but not to hrIL-8. Finally, T-cell chemotaxis was also inhibited by db-cAMP. It is concluded that attenuation of T-cell chemotaxis to two chemoattractants of relevance to asthma pathogenesis can be achieved via phosphodiesterase inhibition and increased intracellular 3', 5'-cyclic monophosphate using drugs active on cyclic nucleotide phosphodiesterase. This action may explain the anti-inflammatory effects of theophylline and related drugs in asthma.
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PMID:Phosphodiesterase and cyclic adenosine monophosphate-dependent inhibition of T-lymphocyte chemotaxis. 1070 3

Theophylline, a known phosphodiesterase inhibitor, has been widely used as an additional bronchodilator in asthmatic patients who are not adequately controlled on high-doses of inhaled steroids. However, there is growing evidence that theophylline may also have anti-inflammatory or immunomodulatory effects in asthma. This study investigated whether theophylline administration has an impact on serum levels of interleukin (IL)-4 and IL-5 in asthmatic patients. Eight asymptomatic patients aged 30+/-1.5 yrs (mean +/- SEM) with mild atopic asthma were given a single daily dose of theophylline 150 mg or placebo in an on (theophylline)-off (placebo)-on (theophylline)-off (placebo) protocol with a 3-week duration of each on- or off- interval. Determination of serum IL-4 and IL-5 was done at baseline for all subjects and on the last day of each 3-week interval for the patients under study. Serum IL-4 levels were: 35+/-6 (baseline), 19+/-3 (on-1 interval), 29.5+/-4 (off-2), 15+/-2 (on-3) and 26+/-4 pg x mL(-1) (off-4), while IL-5 levels were 27+/-5, 18+/-4, 28+/-5, 17+/-4 and 28+/-5 pg x mL(-1), respectively. Spirometry was unchanged during the study and serum theophylline levels at the end of the two on-periods were 4.5+/-0.05 and 4.2+/-0.07 microg x mL(-1), while all patients remained asymptomatic. In conclusion, the administration of a low, single, daily dose of oral theophylline in asymptomatic patients with mild atopic asthma seems to reduce circulating interleukin-4 and interleukin-5.
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PMID:Theophylline induces a reduction in circulating interleukin-4 and interleukin-5 in atopic asthmatics. 1083 23

To evaluate the potential inhibitory effect of theophylline on the pulmonary oxidative stress in asthma and chronic obstructive pulmonary disease (COPD), we concomitantly measured the blood levels of theophylline, a non-selective phosphodiesterase (PDE) inhibitor and lipid peroxides as an index of oxidative stress. The plasma levels of lipid peroxides were significantly elevated in patients with asthma (3.48 +/- 0.11 nmol ml(-1); mean +/- SEM; n=21, P<0.01), non- or ex-smoking patients with COPD (3.55 +/- 0.11 nmol ml(-1); n = 20, P<0.01), and current-smoking patients with COPD (3.53 +/- 0.15 nmol ml(-1); n = 15, P<0.01), respectively, as compared to those of non-smoking controls (3.02 +/- 0.08 nmol ml(-1); n = 19). There was a significant negative correlation between the plasma level of lipid peroxides and the forced expiratory volume in 1 sec (FEV1)% of forced vital capacity in these subjects (r = -0.304; n = 75, P < 0.01). In asthmatics, there was a significant negative correlation between the plasma level of lipid peroxides and the serum level of theophylline (r = -0.495; n = 18, P<0.05). These results suggest that there may be increased oxidative stress in patients with asthma and COPD, and indicate that oxidative stress could possibly attribute to the pathophysiology of asthma and COPD in leading to airflow obstruction and that theophylline could potentially inhibit oxidative stress in the process of bronchopulmonary inflammation in asthmatics.
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PMID:Evidence of oxidative stress in asthma and COPD: potential inhibitory effect of theophylline. 1092 64


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