Mechanisms underlying the contraction induced by bradykinin in the guinea pig epithelium-denuded trachea

2002 ◽  
Vol 80 (4) ◽  
pp. 360-367 ◽  
Author(s):  
Valfredo Schlemper ◽  
João B Calixto
Keyword(s):  
Nitric Oxide ◽  
Guinea Pig ◽  
Rank Order ◽  
Nitric Oxide Synthase Inhibitor ◽  
Cox Inhibitors ◽  
Cyclooxygenase 1 ◽  
Cox Inhibitor ◽  
Cox 2 ◽  
Synthase Inhibitor ◽  
Cox 1

This study investigates some of the mechanisms by which bradykinin (BK) triggers contraction of epithelium-denuded strips of guinea pig trachea (GPT). Cumulative or single additions of BK, T-BK, L-BK, or ML-BK in the presence of captopril (30 µM) produced graded GPT contractions with the following rank order of potency (EC50 level): T-BK (31.3 nM) > BK (40.0 nM) > L-BK (56.0 nM) > ML-BK (77.0 nM). BK-induced contraction (100 nM) in GPT was completely inhibited by either HOE 140 or NPC 17731 with mean IC50 values of 17 and 217 nM, respectively. Addition of BK (100 nM) at 30 min intervals, induced progressive tachyphylaxis, which was complete after 4 h. The tachyphylaxis induced by BK was unaffected by L-NOARG (nitric oxide synthase inhibitor, 100 µM) or valeryl salicylate (a cyclooxygenase-1 (COX-1) inhibitor, 30 µM), but was prevented by a low concentration of indomethacin, diclofenac (non-selective COX inhibitors, 3 nM each) or by NS 398 (a COX-2 inhibitor, 10 nM). Furthermore, higher concentrations of indomethacin, diclofenac, phenidone (a lypooxygenase (LOX) and COX inhibitor), or NS 398, caused graded inhibition of BK-induced contraction, with mean IC50 values of 0.28, 0.08, 46.37, and 0.15 µM, respectively. Together, these results suggest that BK-induced contraction in GPT involves activation of B2 receptors and release of prostanoids from COX-2 pathway. Furthermore, the tachyphylaxis induced by BK was insensitive to the nitric oxide and COX-1 inhibitors, but was prevented by non-selective and selective COX-2 inhibitors, indicating a mediation via COX-2-derived arachidonic acid metabolites.Key words: guinea pig trachea, bradykinin, B2 receptors, desensitization, prostaglandins.

Involvement of cyclooxygenase 2 (COX-2) in intrinsic tone of isolated guinea pig

1995 ◽  
Vol 73 (11) ◽  
pp. 1561-1567 ◽  
Author(s):  
L. Charette ◽  
C. Misquitta ◽  
J. Guay ◽  
D. Riendeau ◽  
T. R. Jones
Keyword(s):  
Guinea Pig ◽  
Time Course ◽  
Cyclooxygenase 2 ◽  
Maximal Response ◽  
Pharmacological Agents ◽  
Cyclooxygenase 1 ◽  
Inflammatory Drugs ◽  
Cox 2 ◽  
Cox 2 Inhibitors ◽  
Cox 1

Indomethacin and related nonsteroidal anti-inflammatory drugs relax prostanoid-dependent intrinsic tone of isolated guinea pig trachea by inhibiting cyclooxygenase (COX). Recently, a second isoform of COX (COX-2) was discovered, which differed from COX-1 with respect to protein structure, transcriptional regulation, and susceptibility to inhibition by pharmacological agents. It is now known that indomethacin nonselectively inhibits COX-1 and COX-2, whereas NS-398 is a selective inhibitor of COX-2. In the present study we compared the activity of a selective (NS-398) and nonselective (indomethacin) COX-2 inhibitor on intrinsic tone of isolated guinea pig trachea. NS-398 ≥ indomethacin produced a reversal of intrinsic tone with a similar concentration-dependent (10 nM to 1 μM) time course (Tmax approximately 20–45 min), potency (EC50 1.7 and 5.6 nM, respectively), and maximal response. Contractions to cholinergic nerve stimulation (45 V, 0.5 ms, 0.1–32 Hz) and histamine were similarly modulated in tissues relaxed with the selective or nonselective COX-2 inhibitors. Immunoblot analyses showed that COX-2 protein synthesis was induced in both the cartilage and smooth muscle portions of the trachea during changes in intrinsic tone. These findings are consistent with pharmacological results and provide the first demonstration that prostanoid tone in isolated guinea pig trachea is dependent on COX-2 activity. The results also suggest that the activity of indomethacin in this preparation is likely related to COX-2 inhibition.Key words: cyclooxygenase 2, relaxation, guinea pig trachea, cyclooxygenase 1.

scholarly journals Comparative Analysis of Pharmacologic and/or Genetic Disruption of Cyclooxygenase-1 and Cyclooxygenase-2 Function in Female Reproduction in Mice*

Endocrinology ◽  
2001 ◽  
Vol 142 (7) ◽  
pp. 3198-3206 ◽  
Author(s):  
Jeff Reese ◽  
Xuemei Zhao ◽  
Wen-Ge Ma ◽  
Naoko Brown ◽  
Timothy J. Maziasz ◽  
...  
Keyword(s):  
Early Pregnancy ◽  
Synergistic Effects ◽  
Female Reproduction ◽  
Cox Inhibitors ◽  
Cyclooxygenase 1 ◽  
Simultaneous Inhibition ◽  
Cox 2 ◽  
Alternative Sources ◽  
First Time ◽  
Cox 1

Abstract Cyclooxygenase (COX)-derived prostaglandins are critical in female reproduction. Gene targeting studies show that ovulation, fertilization, implantation, and decidualization are defective in COX-2 deficient mice. We used genetic and pharmacologic approaches to perturb COX function and examine the differential and synergistic effects of inhibition of COX-1, COX-2, or of both isoforms on reproductive outcomes during early pregnancy in mice. The results demonstrate that simultaneous inhibition of COX-1 and COX-2 produces more severe effects on early pregnancy events than inhibition of either isoform alone. The effects of pharmacological inhibition of COX-2 on female reproductive functions were less severe than the null mutation of the COX-2 gene. A combined approach showed that COX-2 inhibition in COX-1−/− mice induced complete reproductive failure, suggesting a lack of alternative sources of prostaglandin synthesis. This investigation raises caution regarding the indiscriminate use of COX inhibitors and shows for the first time the distinct and overlapping pathways of the cyclooxygenase systems in female reproduction.

Synthesis and evaluation of new benzimidazole-based COX inhibitors: a naproxen-like interaction detected by STD-NMR

RSC Advances ◽  
2015 ◽  
Vol 5 (61) ◽  
pp. 49098-49109 ◽  
Author(s):  
Luísa C. R. Carvalho ◽  
Daniela Ribeiro ◽  
Raquel S. G. R. Seixas ◽  
Artur M. S. Silva ◽  
Mariana Nave ◽  
...  
Keyword(s):  
Pharmacological Activity ◽  
Cox Inhibitors ◽  
Cyclooxygenase 1 ◽  
Inflammatory Drugs ◽  
Std Nmr ◽  
Cox 2 ◽  
Anti Inflammatory ◽  
Cox 1

Non-steroidal anti-inflammatory drugs exert their pharmacological activity through inhibition of cyclooxygenase 1 and 2 (COX-1 and COX-2).

scholarly journals Differential contribution of COX-1 and COX-2 derived prostanoids to cortical spreading depression—Evoked cerebral oligemia

2016 ◽  
Vol 37 (3) ◽  
pp. 1060-1068 ◽  
Author(s):  
Helaine Gariepy ◽  
Jun Zhao ◽  
Dan Levy
Keyword(s):  
Cortical Spreading Depression ◽  
Spreading Depression ◽  
Selective Inhibition ◽  
Doppler Flowmetry ◽  
Relative Contribution ◽  
Cox Inhibitor ◽  
Cox 2 ◽  
Synthase Inhibitor ◽  
Later Phase ◽  
Cox 1

Cortical spreading depression (CSD) is considered a significant phenomenon for human neurological conditions and one of its key signatures is the development of persistent cortical oligemia. The factors underlying this reduction in cerebral blood flow (CBF) remain incompletely understood but may involve locally elaborated vasoconstricting eicosanoids. We employed laser Doppler flowmetry in urethane-anesthetized rats, together with a local pharmacological blockade approach, to test the relative contribution of cyclooxygenase (COX)-derived prostanoids to the oligemic response following CSD. Administration of the non-selective COX inhibitor naproxen completely inhibited the oligemic response. Selective inhibition of COX-1 with SC-560 preferentially reduced the early reduction in CBF while selective COX-2 inhibition with NS-398 affected only the later response. Blocking the action of thromboxane A2 (TXA2), using the selective thromboxane synthase inhibitor ozagrel, reduced only the initial CBF decrease, while inhibition of prostaglandin F2alpha action, using the selective FP receptor antagonist AL-8810, blocked the later phase of the oligemia. Our results suggest that the long-lasting oligemia following CSD consists of at least two distinct temporal phases, mediated by preferential actions of COX-1- and COX-2-derived prostanoids: an initial phase mediated by COX-1 that involves TXA2 followed by a later phase, mediated by COX-2 and PGF2alpha.

scholarly journals Synthesis and theoretical activity evaluation of a new steroid-oxazolone derivative against COX1-1 and COX-2

2019 ◽  
Vol 9 (4) ◽  
pp. 4107-4113
Keyword(s):  
Elemental Analysis ◽  
Cox Inhibitors ◽  
Activity Evaluation ◽  
Docking Model ◽  
Cox Inhibitor ◽  
Cox 2 ◽  
Cox 1

There are some reports for the preparation of several drugs as cyclooxygenase (COX) inhibitors; however, some reagents used in the preparation are expensive and difficult to handle. The aim of this study was to synthesize a steroid-oxazolone derivativeusing some reactions such as i) hydroxylation-amiination; ii) amidation; iii) alkynyl-addition; iv) aldolization and iv) imination. In addition, a theoretical ass was carried out to evaluate the interaction of both COX-1 and COX-2 with the steroid-oxazolone derivativeusing indomethacin and rofecoxib as controls in a docking model. The structure of the compounds obtained was confirmed through elemental analysis, spectroscopy and spectrometry data. The results showed that there are differences between the interaction of the steroidoxazolone derivativewith both COX 1 and COX 2 compared with the bound of indomethacin and rofecoxib with this type of enzymes. These data suggest that the steroid-oxazolone derivativecould be a good candidate as COX-inhibitor translated as a possible drug for treatment of pain.

Effects of cyclooxygenase inhibition on canine coronary artery blood flow and thrombosis

2008 ◽  
Vol 294 (1) ◽  
pp. H145-H155 ◽  
Author(s):  
Ting-Ting Hong ◽  
Jinbao Huang ◽  
Terrance D. Barrett ◽  
Benedict R. Lucchesi
Keyword(s):  
Coronary Artery ◽  
Vascular Reactivity ◽  
Thrombus Formation ◽  
Normal Coronary Artery ◽  
Cox Inhibitors ◽  
Inflammatory Conditions ◽  
Cox Inhibitor ◽  
Cox 2 ◽  
Cox 2 Inhibitors ◽  
Cox 1

This study was designed to determine the effect of inhibitors of cyclooxygenase (COX)-1, COX-2, and the nonselective COX inhibitor naproxen on coronary vasoactivity and thrombogenicity under baseline and lipopolysaccharide (LPS)-induced inflammatory conditions. We hypothesize that endothelial COX-1 is the primary COX isoform in the canine normal coronary artery, which mediates arachidonic acid (AA)-induced vasodilatation. However, COX-2 can be induced and overexpressed by inflammatory mediators and becomes the major local COX isoform responsible for the production of antithrombotic prostaglandins during systemic inflammation. The interventions included the selective COX-1 inhibitor SC-560 (0.3 mg/kg iv), the selective COX-2 inhibitor nimesulide (5 mg/kg iv), or the nonselective COX inhibitor naproxen (3 mg/kg iv). The selective prostacyclin (IP) receptor antagonist RO-3244794 (RO) was used as an investigational tool to delineate the role of prostacyclin (PGI2) in modulating vascular reactivity. AA-induced vasodilatation of the left circumflex coronary artery was suppressed to a similar extent by each of the COX inhibitors and RO. The data suggest that AA-induced vasodilatation in the normal coronary artery is mediated by a single COX isoform, the constitutive endothelial COX-1, which is reported to be susceptible to COX-2 inhibitors. The effect of the COX inhibitors on thrombus formation was evaluated in a model of carotid artery thrombosis secondary to electrolytic-induced vessel wall injury. Pretreatment with LPS (0.5 mg/kg iv) induced a systemic inflammatory response and prolonged the time-to-occlusive thrombus formation, which was reduced in the LPS-treated animals by the administration of nimesulide. In contrast, neither SC-560 nor naproxen influenced the time to thrombosis in the animals pretreated with LPS. The data are of significance in view of reported adverse cardiovascular events observed in clinical trials involving the use of selective COX-2 inhibitors, thereby suggesting that the endothelial constitutive COX-1 and the inducible vascular COX-2 serve important functions in maintaining vascular homeostasis.

scholarly journals Compensatory Prostaglandin E2 Biosynthesis in Cyclooxygenase 1 or 2 Null Cells

1998 ◽  
Vol 187 (4) ◽  
pp. 517-523 ◽  
Author(s):  
Kanyawim Kirtikara ◽  
Scott G. Morham ◽  
Rajendra Raghow ◽  
Stanley J. F. Laulederkind ◽  
Takuro Kanekura ◽  
...  
Keyword(s):  
Prostaglandin E2 ◽  
Wild Type ◽  
Acidic Fibroblast Growth Factor ◽  
Cox Inhibitors ◽  
Cyclooxygenase 1 ◽  
Enhanced Expression ◽  
Key Enzyme ◽  
Cox 2 ◽  
Factor Α ◽  
Cox 1

Prostaglandin E2 (PGE2) production in immortalized, nontransformed cells derived from wild-type, cyclooxygenase 1–deficient (COX-1−/−) or cyclooxygenase 2–deficient (COX-2−/−) mice was examined after treatment with interleukin (IL)-1β, tumor necrosis factor α, acidic fibroblast growth factor, and phorbol ester (phorbol myristate acetate). Compared with their wild-type counterparts, COX-1−/− or COX-2−/− cells exhibited substantially enhanced expression of the remaining functional COX gene. Furthermore, both basal and IL-1–induced expression of cytosolic phospholipase A2 (cPLA2), a key enzyme-regulating substrate mobilization for PGE2 biosynthesis, was also more pronounced in both COX-1−/− and COX-2−/− cells. Thus, COX-1−/− and COX-2−/− cells have the ability to coordinate the upregulation of the alternate COX isozyme as well as cPLA2 genes to overcome defects in prostaglandin biosynthetic machinery. The potential for cells to alter and thereby compensate for defects in the expression of specific genes such as COX has significant clinical implications given the central role of COX in a variety of disease processes and the widespread use of COX inhibitors as therapeutic agents.

Prostaglandins mediate tonic contraction of the guinea pig and human gallbladder

2007 ◽  
Vol 292 (1) ◽  
pp. G409-G418 ◽  
Author(s):  
Ping Cong ◽  
Zuo-Liang Xiao ◽  
Piero Biancani ◽  
Jose Behar
Keyword(s):  
Protein Expression ◽  
Tonic Contraction ◽  
Human Gallbladder ◽  
Small Interference Rna ◽  
Cox Inhibitors ◽  
Cox Inhibitor ◽  
Cox 2 ◽  
Dose Dependent Decrease ◽  
Dose Dependent ◽  
Cox 1

The gallbladder (GB) maintains tonic contraction modulated by neurohormonal inputs but generated by myogenic mechanisms. The aim of these studies was to examine the role of prostaglandins in the genesis of GB myogenic tension. Muscle strips and cells were treated with prostaglandin agonists, antagonists, cyclooxygenase (COX) inhibitors, and small interference RNA (siRNA). The results show that PGE2, thromboxane A2 (TxA2), and PGF2α cause a dose-dependent contraction of muscle strips and cells. However, only TxA2 and PGE2 (E prostanoid 1 receptor type) antagonists induced a dose-dependent decrease in tonic tension. A COX-1 inhibitor decreased partially the tonic contraction and TxB2 (TxA2 stable metabolite) levels; a COX-2 inhibitor lowered the tonic contraction partially and reduced PGE2 levels. Both inhibitors and the nonselective COX inhibitor indomethacin abolished the tonic contraction. Transfection of human GB muscle strips with COX-1 siRNA partially lowered the tonic contraction and reduced COX-1 protein expression and TxB2 levels; COX-2 siRNA also partially reduced the tonic contraction, the protein expression of COX-2, and PGE2. Stretching muscle strips by 1, 2, 3, and 4 g increased the active tension, TxB2, and PGE2 levels; a COX-1 inhibitor prevented the increase in tension and TxB2; and a COX-2 inhibitor inhibited the expected rise in tonic contraction and PGE2. Indomethacin blocked the rise in tension and TxB2 and PGE2 levels. We conclude that PGE2 generated by COX-2 and TxA2 generated by COX-1 contributes to the maintenance of GB tonic contraction and that variations in tonic contraction are associated with concomitant changes in PGE2 and TxA2 levels.

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