bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitric oxide synthase and cyclo‐oxygenase pathways in the inflammatory response induced by zymosan in the rat air pouch
Authors: PayÁ Miguel , GarcÍA PASTOR Pablo , Coloma Julio , JosÉ ALCARAZ M. 
Published: August 2006

We have studied the participation of nitric oxide (NO) in an animal model of inflammation, the rat air pouch stimulated with zymosan.
Saline or zymosan was injected into 6‐day rat air pouches at different time points and measurements were made of cell migration, levels of nitrite/nitrate (NO2−/NO3−), prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and secretory phospholipase A2 (sPLA2) in exudates. Nitric oxide synthase (NOS) activity was determined in high speed supernatants from cells present in pouch exudates. Western blot analysis was also performed on these samples.
Zymosan injection induced a time‐dependent increase in leukocyte infiltration, NO2−/NO3− levels and cellular NOS activity that reached a peak by 8 h. Western blot analysis showed the same time course for induction of NOS protein. Colchicine administration to rats inhibited cellular infiltration and decreased the levels of NO metabolites and cellular NOS activity zymosan‐injected air pouch at 8 h. NOS activity was present in polymorphonuclear leukocytes (PMNs) and monocytes, but not in the lymphocytes present in exudates. This enzyme is calcium‐independent and needs NADPH for activity. PGE2 levels in exudates showed a time course inverse to that of NOS activity and NO metabolites, with maximum levels of PGE2 observed at 4 h after zymosan injection.
Administration of NG‐nitro‐l‐arginine methyl ester (l‐NAME) or aminoguanidine to rats significantly reduced cellular NOS activity, NO2−/NO3− levels and chemiluminescence, whereas they were without effect on cell migration and degranulation, eicosanoid levels and sPLA2 activity.
Treatment of animals with dexamethasone inhibited cellular NOS activity, NO2−/NO3− levels, chemiluminescence and the increase in the levels of PGE2 and LTB4, with only a weak effect on elastase release.
Administration of the selective cyclo‐oxygenase‐2 (COX‐2) inhibitor NS398 to rats strongly reduced PGE2 levels in exudates without affecting NO metabolites or NOS activity at 4 h after zymosan injection.
Our data indicate that NOS is induced in the zymosan‐stimulated rat air pouch model of inflammation. This enzyme is expressed in the cells migrating into the air pouch and caused an increased production of NO metabolites in exudates. The results also suggest the presence of an earlier phase in which eicosanoids play the main role, with participation of COX‐2 activity, and a later phase mediated by NO. The endogenous release of NO does not modify prostaglandin biosynthesis in this in vivo model.

British Journal of Pharmacology (1997) 120, 1445–1452; doi:10.1038/sj.bjp.0701073
Differential effects of diadenosine phosphates on purinoceptors in the rat isolated perfused kidney
Authors: Van Der Giet Markus , Khattab Mohammed , Börgel Jan , Schlüter Hartmut , Zidek Walter 
Published: August 2006

The activation of various purinoceptors in rat renal vasculature by P1,P2‐diadenosine pyrophosphate (Ap2A), P1,P3‐diadenosine triphosphate (Ap3A), P1,P4‐diadenosine tetraphosphate (Ap4A), P1,P5‐diadenosine pentaphosphate (Ap5A), P1,P6‐diadenosine hexaphosphate (Ap6A) was studied by measuring their effects of perfusion pressure of a rat isolated perfused kidney.
The vasoconstrictive response to Ap5A was completely due to P2X purinoceptor activation, that to Ap4A and Ap6 was P2X purinoceptor mediated to a large extent, as evidenced by the inhibitory effects of suramin and pyridoxal‐phosphate‐6‐azophenyl‐2′,4′‐disulphonic acid tetrasodium (PPADS).
The vasoconstrictive effects of Ap2A and Ap3A were mostly due to stimulation of A1‐receptors, as shown by the inhibitory effect of 8‐cyclopentyl‐1,3‐dipropylxanthine (DPCPX).
The vasoconstrictive response to Ap6A was partially insensitive to A1 and P2X purinoceptor blockers.
In raised tone preparations Ap2A and Ap3A evoked vasodilatation, which was blocked by the A2 receptor blocker, 3,7‐dimethyl‐1‐propargylxanthine (DMPX).
In raised tone preparations Ap4A evoked vasodilatation when the P2‐purinoceptors were blocked by suramin.
The activation of different purinoceptor subtypes by diadenosine phosphates critically depends on the number of phosphate groups.

British Journal of Pharmacology (1997) 120, 1453–1460; doi:10.1038/sj.bjp.0701074
Regulation of the resting potential of rabbit pulmonary artery myocytes by a low threshold, O2‐sensing potassium current*
Authors: Osipenko Oleg N. , Mark Evans A. , Gurney Alison M. 
Published: August 2006

The contributions of specific K+ currents to the resting membrane potential of rabbit isolated, pulmonary artery myocytes, and their modulation by hypoxia, were investigated by use of the whole‐cell, patch‐clamp technique.
In the presence of 10 μm glibenclamide the resting potential (−50±4 mV, n=18) was unaffected by 10 μm tetraethylammonium ions, 200 nm charybdotoxin, 200 nm iberiotoxin, 100 μm ouabain or 100 μm digitoxin. The negative potential was therefore maintained without ATP‐sensitive (KATP) or large conductance Ca2+‐sensitive (BKCa) K channels, and without the Na+‐K+ATPase.
The resting potential, the delayed rectifier current (IK(V)) and the A‐like K+ current (IK(A)) were all reduced in a concentration‐dependent manner by 4‐aminopyridine (4‐AP) and by quinine.
4‐AP was equally potent at reducing the resting potential and IK(V), 10 mm causing depolarization from −44 mV to −22 mV with accompanying inhibition of IK(V) by 56% and IK(A) by 79%. In marked contrast, the effects of quinine on resting potential were poorly correlated with its effects on both IK(A) and IK(V). At 10 mm, quinine reduced IK(V) and IK(A) by 47% and 38%, respectively, with no change in the resting potential. At 100 μm, both currents were almost abolished while the resting potential was reduced <50%. Raising the concentration to 1 mm had little further effect on IK(A) or IK(V), but essentially abolished the resting potential.
Reduction of the resting potential by quinine was correlated with inhibition of a voltage‐gated, low threshold, non‐inactivating K+ current, IK(N). Thus, 100 μm quinine reduced both IK(N) and the resting potential by around 50%.
The resting membrane potential was the same whether measured after clamping the cell at −80 mV, or immediately after a prolonged period of depolarization at 0 mV, which inactivated IK(A) and IK(V), but not IK(N).
When exposed to a hypoxic solution, the O2 tension near the cell fell from 125±6 to 14±2 mmHg (n=20), resulting in a slow depolarization of the myocyte membrane to −35±3 mV (n=16). The depolarization occurred without a change in the amplitude of IK(V) or IK(A), but it was accompanied by 60% inhibition of IK(N) at 0 mV.
Our findings suggest that the resting potential of rabbit pulmonary artery myocytes depends on IK(N), and that inhibition of IK(N) may mediate the depolarization induced by hypoxia.

British Journal of Pharmacology (1997) 120, 1461–1470; doi:10.1038/sj.bjp.0701075
Ocular inflammation induced by electroconvulsive treatment: contribution of nitric oxide and neuropeptides mobilized from C‐fibres
Authors: Wang Zun‐Yi , Waldeck Kristian , Grundemar Lars , Håkanson Rolf 
Published: August 2006

Electroconvulsive treatment (ECT) of rabbits produced ocular inflammation consisting of conjunctival hyperaemia, miosis and protein extravasation into the aqueous humour, reflected by the so‐called aqueous flare response (AFR); the maximal reduction in pupil size was 3.8±0.1 mm (s.e. of mean, n=16) while the maximal AFR was 28.1±2.8 (arbitrary units).
ECT also caused release of substance P (SP), pituitary adenylate cyclase‐activating peptide (PACAP)‐27, ‐38 and calcitonin gene‐related peptide (CGRP). The concentrations of SP and CGRP in the aqueous humour of normal, untreated eyes were 10.6±1.4 and 117.4±12.4 pmol l−1, respectively, while the concentrations of PACAP‐27 and ‐38 were below the detection limit. After ECT the concentrations of SP, PACAP‐27, ‐38 and CGRP were 65.0±9.6, 46.9±8.4, 50.2±5.4 and 1109.9±133.1 pmol l−1, respectively (s.e. of mean, n=12). Conceivably, ECT evoked an antidromic activation of sensory neurones in the trigeminal ganglion with the consequent release of neuropeptides from C‐fibres in the uvea and the development of neurogenic inflammation.
Rabbits received the nitric oxide (NO) synthase inhibitor, NG‐nitro‐l‐arginine methyl ester (l‐NAME, 200 mg kg−1, i.v.). This pretreatment inhibited the ECT‐evoked conjunctival hyperaemia, miosis and AFR; under these circumstances the maximal reduction in pupil size was 1.9±0.1 mm while the maximal AFR was 2.7±0.9 (n=16). l‐NAME also inhibited the ECT‐evoked release of SP, PACAP‐27, ‐38 and CGRP into the aqueous humour; the concentrations of SP and CGRP were 13.2±1.5 and 204.8±33.5 pmol l−1, respectively, while PACAP‐27 and ‐38 were below the detection limit (n=12).
The ECT‐evoked miosis was also inhibited by pretreatment with the tachykinin receptor antagonist d‐Pal9 spantide II (90 nmol, intravitreal injection); under these circumstances the maximal reduction in pupil size was only 0.7±0.03 mm, indicating an important role for SP in the miotic response. Pretreatment of the eye with capsaicin, which is known to cause functional ablation of C‐fibres, inhibited the conjunctival hyperaemia, miosis and AFR by 4050%; the maximal reduction in pupil size being 2.2±0.2 mm and the maximal AFR 13.8±2.1 (arbitrary units) (n=8).
The results suggest (1) that ECT evokes ocular inflammation through antidromic C‐fibre activation; (2) that SP contributes to the ECT‐evoked miosis; and (3) that NO contributes to the antidromic C‐fibre activation and possibly to the vascular responses mediated by the C‐fibre transmitters.

British Journal of Pharmacology (1997) 120, 1491–1495; doi:10.1038/sj.bjp.0701083
The in vitro pulmonary vascular effects of FK409 (nitric oxide donor): a study in normotensive and pulmonary hypertensive rats
Authors: Wanstall Janet C , Kaye Jacqueline A , Gambino Agatha 
Published: August 2006

Vasorelaxant responses to the nitric oxide (NO) donor, FK409 ((±)‐(E)‐4‐ethyl‐2‐[(E)‐hydroxyimino]‐5‐nitro‐3‐hexenamide), were evaluated on precontracted isolated ring preparations of main pulmonary artery and intralobar pulmonary artery from rats.
On main pulmonary artery FK409 fully reversed the precontractions. Responses were inhibited by methylene blue but were independent of the endothelium. The potency (−log EC50) of FK409 was the same on preparations contracted with noradrenaline (7.62) or the thromboxane‐mimetic, U44619 (7.63).
On intralobar pulmonary artery FK409 caused only 80% reversal of the precontraction and was 2 fold less potent than on main pulmonary artery. These differences in maximum response and potency between main and intralobar arteries are in keeping with previous findings with other NO donors.
Pulmonary hypertension was induced in rats by chronic exposure to hypoxia (10% O2) for 1 or 4 weeks. Main pulmonary arteries from 1 week hypoxic rats had inherent tone and showed spontaneous contractile activity. In these arteries FK409 reversed not only the precontraction induced by noradrenaline but also the inherent tone. However, FK409 was 17 fold less potent than in control arteries, reflecting previous findings with other NO donors. Main pulmonary arteries from 4 week hypoxic rats had minimal inherent tone and were quiescent and FK409 was 4.5 fold less potent than in control arteries. In intralobar pulmonary arteries from 4 week hypoxic rats FK409 was 12 fold less potent than in controls.
Treatment of arteries with either (a) in vitro hypoxic conditions (PO2 of solution in organ bath <10 mmHg) or (b) superoxide dismutase (SOD; 150 u ml−1) together with catalase (1200 u ml−1) significantly increased the potency of FK409 in preparations from hypoxic rats but had no effect on the potency in control preparations. Neither SOD nor catalase, alone, nor the nitric oxide synthase inhibitor, NG‐nitro‐L‐arginine methyl ester, had any effect on the potency of FK409 in preparations from control or hypoxic rats.
It is concluded that the reduction in potency of FK409 seen in pulmonary arteries from rats with chronic hypoxic pulmonary hypertension may be due in part to the presence of one or more reactive oxygen species (either hydroxyl or superoxide plus hydrogen peroxide).

British Journal of Pharmacology (1997) 121, 280–286; doi:10.1038/sj.bjp.0701105
Central involvement of kinin B1 and B2 receptors in the febrile response induced by endotoxin in rats
Authors: Coelho M M , Oliveira C R , Pajolla G P , Calixto J B , Pelá I R 
Published: August 2006

The effect of central injection of selective kinin B1 and B2 receptor antagonists on the febrile response induced by endotoxin (E. coli lipopolysaccharide, LPS) in rats was investigated.
Intracerebroventricular (i.c.v.) injection of a selective B2 receptor antagonist (Hoe‐140, 8 nmol) reduced the early (0–2 h), but increased the late phase (4–6 h) of the febrile response induced by intravenous (i.v.) injection of LPS (0.5 μg kg−1).
Co‐administration of Hoe‐140 (8 nmol, i.c.v.) with LPS (0.5 μg kg−1, i.v.), followed 2.5 h later by the i.c.v. injection of a selective B1 receptor antagonist [des‐Arg9‐Leu8]‐bradykinin (BK, 8 nmol), significantly reduced the febrile response induced by LPS throughout the whole experimental period.
Intravenous injection of Hoe‐140 (1 mg kg−1) significantly reduced the febrile response induced by LPS (0.5 μg kg−1, i.p.).
Pretreatment (24 h) with LPS (0.5 μg kg−1, i.v.) reduced the febrile response induced by BK or [Tyr8]‐BK (both, 5 nmol, i.c.v.), but markedly increased the febrile response induced by [des‐Arg9]‐BK (5 nmol, i.c.v.). The response induced by [des‐Arg9]‐BK in LPS‐pretreated rats was significantly inhibited by co‐injection of [des‐Arg9‐Leu8]‐BK (15 nmol, i.c.v.).
The results suggest that kinins are involved in the induction of LPS‐induced fever and that central B2 and B1 receptors are activated during the initial and late phase of this response, respectively. The results also suggest that downregulation and/or desensitization of B2 receptors and induction and/or upregulation of B1 receptors in LPS‐pretreated animals may have a significant pathophysiologcal role in the induction and maintenance of fever. These observations may be specifically important in the case of chronic inflammatory conditions, because the BK metabolite [des‐Arg9]‐BK, so far considered an inactive metabolite, acquires an active and relevant role with the progressive expression of B1 receptors that occurs in such states.

British Journal of Pharmacology (1997) 121, 296–302; doi:10.1038/sj.bjp.0701110
Effects of phosphodiesterase inhibitors on human lung mast cell and basophil function
Authors: Weston Marie C , Anderson Nicola , Peachell Peter T 
Published: August 2006

The non‐hydrolysable cyclic AMP analogue, dibutyryl (Bu2)‐cyclic AMP, inhibited the stimulated release of histamine from both basophils and human lung mast cells (HLMC) in a dose‐dependent manner. The concentrations required to inhibit histamine release by 50% (IC50) were 0.8 and 0.7 mM in basophils and HLMC, respectively. The cyclic GMP analogue, Bu2‐cyclic GMP, was ineffective as an inhibitor of histamine release in basophils and HLMC.
The non‐selective phosphodiesterase (PDE) inhibitors, theophylline and isobutyl‐methylxanthine (IBMX) inhibited the IgE‐mediated release of histamine from both human basophils and HLMC in a dose‐dependent fashion. IBMX and theophylline were more potent inhibitors in basophils than HLMC. IC50 values for the inhibition of histamine release were, 0.05 and 0.2 mM for IBMX and theophylline, respectively, in basophils and 0.25 and 1.2 mM for IBMX and theophylline in HLMC.
The PDE 4 inhibitor, rolipram, attenuated the release of both histamine and the generation of sulphopeptidoleukotrienes (sLT) from activated basophils at sub‐micromolar concentrations but was ineffective at inhibiting the release of histamine and the generation of both sLT and prostaglandin D2 (PGD2) in HLMC. Additional PDE 4 inhibitors, denbufylline, Ro 20–1724, RP 73401 and nitraquazone, were all found to be effective inhibitors of mediator release in basophils but were ineffective in HLMC unless high concentrations (1 mM) were employed.
Neither 8‐methoxymethyl IBMX (PDE 1 inhibitor), zaprinast (PDE 5 inhibitor) nor a range of PDE 3 inhibitors (siguazodan, SKF 94120, SKF 95654) were effective inhibitors of mediator release from either basophils or HLMC.
In basophils, rolipram acted to potentiate the inhibitory effects of the adenylate cyclase activator, forskolin, whereas in HLMC, rolipram failed to potentiate the inhibitory effects of forskolin.
Extracts of purified HLMC and basophils hydrolysed cyclic AMP. IBMX (100 μM) inhibited the PDE activity in basophil extracts by 67±7% (P<0.0001) and in HLMC extracts by 63±9% (P<0.0005). The hydrolysis of cyclic AMP by basophil extracts was inhibited by the selective PDE inhibitors (all at 10 μM), rolipram (56±8%, P<0.0001) and the mixed PDE 3/4 inhibitor, Org 30029 (47±9%, P<0.01), whereas 8‐methoxymethyl IBMX, siguazodan and zaprinast were ineffective. In HLMC, rolipram, Org 30029, 8‐methoxymethyl IBMX, siguazodan and zaprinast all inhibited the hydrolysis of cyclic AMP by extracts to a significant (P<0.05) and similar extent (approximately 25% inhibition at 10 μM).
In total, these data suggest that modulation of the PDE 4 isoform can regulate basophil responses whereas an association of the PDE 4 isoform with the regulation of HLMC function remains uncertain.

British Journal of Pharmacology (1997) 121, 287–295; doi:10.1038/sj.bjp.0701115
A site‐directed mutagenesis study on the conserved alanine residue in the distal third intracellular loops of cholecystokininB and neurotensin receptors
Authors: Wang Hung‐Li 
Published: August 2006

An alanine residue at the C‐terminal tail of the third intracellular loop is highly conserved among various Gq protein‐coupled receptors including rat cholecystokininB (CCKB) and neurotensin receptors. To investigate the functional significance of the conserved alanine in the activation of Gq proteins and phospholipase C (PLC) by CCKB and neurotensin receptors, the alanine residue was mutated in the present study. Subsequently, the ability of resulting mutant receptors to activate PLC was investigated by measuring the formation of inositol phosphates (IP) in COS‐7 cells and recording Ca2+‐activated chloride currents from Xenopus oocytes.
Site‐directed mutagenesis was performed to mutate alanine at position 332 of rat CCKB receptor to glutamate. When the (A332E) mutant receptor was expressed in COS‐7 cells and Xenopus oocytes, the efficacy and the potency of sulphated cholecystokinin octapeptide (CCK‐8) to stimulate polyphosphoinositide hydrolysis in COS‐7 cells and evoke calcium‐dependent Cl− currents in oocytes were not significantly affected.
Alanine residue at position 302 of rat neurotensin receptor was also mutated to glutamate. When expressed in COS‐7 cells and Xenopus oocytes, the resulting (A302E) mutant receptor was strongly defective in stimulating phosphatidylinositol turnover in COS‐7 cells and evoking Ca2+‐dependent chloride currents in oocytes.
In summary, the present study demonstrates that alanine residue at the C‐terminus of third cytoplasmic domain is required for the full activation of Gq proteins and PLC by neurotensin receptors. However, in contrast to other Gq protein‐coupled receptors, alanine at the distal third intracellular loop does not play a significant role in CCKB receptor activation of PLC.

British Journal of Pharmacology (1997) 121, 310–316; doi:10.1038/sj.bjp.0701117
NO‐dependent and NO‐independent IL‐1 production by a human colonic epithelial cell line under inflammatory stress
Authors: Vallette Geneviève , Jarry Anne , Lemarre Philippe , Branka Jean‐Eric , Laboisse Christian L 
Published: August 2006

The present study was designed to investigate, in an in vitro model of the human intestinal barrier, the ability of epithelial cells to produce interleukin‐1 (IL‐1), the cellular mechanisms involved in IL‐1 release, and the intracellular signalling pathways involved in IL‐1 up‐regulation during inflammatory stress.
This study was based on the human colonic epithelial cell line HT29‐Cl.16E, maintained as polarized monolayers on filters mounted in culture chambers and treated with various proinflammatory cytokines (interferon γ (IFNγ), tumour necrosis factor α (TNFα), IL‐1β) alone or in combination.
IL‐1 production, restricted to IL‐1α, was induced by the combination of IFNγ/TNFα. When IL‐1β was added to IFNγ/TNFα, it led to an additional production of IL‐1α. IL‐1α release was associated with cell damage, as shown by the correlation between lactate dehydrogenase (LDH) release and extracellular IL‐1 production, and was not accounted for by a secretory mechanism.
Both IFNγ/TNFα and IFNγ/TNFα/IL‐1β induced inducible nitric oxide synthase (iNOS) expression as shown by quantitation of NO2−/NO3− by use of the Griess reagent, quantitation of cells scoring positive with an anti‐iNOS antibody and detection of mRNAs coding for iNOS by RT–PCR. The use of NG‐monomethyl‐L‐arginine (L‐NMMA), an inhibitor of NOS, led to the demonstration of two distinct signalling pathways in IL‐1 production by HT29‐Cl.16E cells, one dependent on NO (L‐NMMA‐sensitive) under treatment with IFNγ/TNFα/IL‐1β, and the other independent of NO (L‐NMMA‐insensitive) under treatment with IFNγ/TNFα.
Moreover, we examined whether a redox‐based mechanism could be responsible for the apparent discrepancy between NO production and NO implication in IL‐1 production under IFNγ/TNFα and IFNγ/TNFα/IL‐1β treatments. Experiments with cysteine, which acts as a powerful reductant, suggest that the nitrosonium character of NO is involved in the NO‐dependent pathway in IL‐1 production.

British Journal of Pharmacology (1997) 121, 187–192; doi:10.1038/sj.bjp.0701118
Effect of L‐dopa alone and with benserazide on the spontaneous activity of striatal neurones in normal and 6‐hydroxydopamine‐lesioned rats
Authors: Chang W Y , Webster R A 
Published: August 2006

The effects of L‐dopa methylester (LDME), an analogue of levodopa, on the spontaneous activity of dopamine sensitive neurones in the rat striatum, after 6‐hydroxydopamine induced degeneration of the nigrostriatal tract were compared with those in unlesioned animals both in the absence and presence of benserazide, a peripheral DOPA decarboxylase inhibitor (PDI).
Studies were performed at 5–7 days post lesion (group 1 animals), at 21 days (group 2) when denervation supersensitivity was evident by contralateral turning to apomorphine and at the same time but following 7 days dosing with LDME plus benserazide (group 3).
In unlesioned animals, LDME alone inhibited spontaneous firing by some 45% over 60 min including a marked but transient early phase which was still present in all lesioned animals even though the later inhibition was significantly reduced in group 1 and 3 animals.
When given after benserazide in unlesioned animals LDME still produced a similar level of overall inhibition but without the early phase. The lesion reduced the overall inhibition, except in group 2 animals, and after chronic dosing (group 3) it was almost absent.
It is proposed that since the early inhibition with LDME alone is still seen after lesion of the nigrostriatal tract but not after the PDI benserazide, it is caused by peripherally formed dopamine and that as the delayed inhibition with LDME alone and after benserazide are all reduced by nigrostriatal lesions, as is its amphetamine like ipsilateral turning, that this depends on locally (striatal) synthesized dopamine.
This study also shows that chronic levodopa/PDI treatment reduces the compensating increased activity of surviving dopaminergic neurones and the functional supersensitivity to dopamine suggests that the long term administration of levodopa may reduce its own utilization and activity in the striatum and in the treatment of Parkinson's Disease.

British Journal of Pharmacology (1997) 121, 331–337; doi:10.1038/sj.bjp.0701133