bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the temporal expression of chemokines and chemokine receptors during experimental granulomatous inflammation: role and expression of MIP‐1α and MCP‐1
Authors: Carollo Maria , Hogaboam Cory M , Kunkel Stephen L , Delaney Stephen , Christie Mark I , Perretti Mauro
Published: January 2005

Chemokine expression and function was monitored in an experimental model of granulomatous tissue formation after injection of croton oil in complete Freund's adjuvant (CO/CFA) into mouse dorsal air‐pouches up to 28 days.

In the first week, mast cell degranulation and leukocyte influx (mononuclear cell, MNC, and polymorphonuclear cell, PMN) were associated with CXCR2, KC and macrophage inflammatory protein (MIP)‐2 mRNA expression, as determined by TaqMan® reverse transcriptase‐polymerase chain reaction. KC (∼400 pg mg protein−1, n=12) and MIP‐2 (∼800 pg mg protein−1, n=12) proteins peaked at day 7, together with myeloperoxidase (MPO) activity. Highest MIP‐1α (>1 ng mg protein−1, n=12) levels were measured at day 3.

After day 7, a gradual increase in CCR2 and CCR5 mRNA, monocyte chemoattractant protein (MCP)‐1 mRNA and protein expression was measured. MCP‐1 protein peaked at day 21 (∼150 pg mg protein−1, n=12) and was predominantly expressed by mast cells. A gradual increase in N‐acetyl‐β‐D‐glucosaminidase (NAG) activity (maximal at 28 days) was also measured.

An antiserum against MIP‐1α did not modify the inflammatory response measured at day 7 (except for a 50% reduction in MIP‐1α levels), but provoked a significant increase in MPO, NAG and MCP‐1 levels as measured at day 21 (n=6, P<0.05). An antiserum to MCP‐1 reduced NAG activity at day 21 but increased MPO activity values (n=8, P<0.05).

In conclusion, we have shown that CO/CFA initiates a complex inflammatory reaction in which initial expression of MIP‐1α serves a protective role whereas delayed expression of MCP‐1 seems to have a genuine pro‐inflammatory role.

British Journal of Pharmacology (2001) 134, 1166–1179; doi:10.1038/sj.bjp.0704371
Anandamide administration into the ventromedial hypothalamus stimulates appetite in rats
Authors: Jamshidi Nazila , Taylor David A
Published: January 2005

This investigation reports the possible role of the endocannabinoid anandamide in modulating appetitive behaviour. Given that cannabinoids have been used clinically to stimulate appetite in HIV and cancer chemotherapy patients, there has been a renewed interest in the involvement of cannabinoids in appetite modulation. This is the first report on the administration of anandamide into the ventromedial hypothalamus. Pre‐satiated rats received an intrahypothalamic injection of anandamide (50 ng 0.5 μl−1) followed by measurement of food intake at 3 h post injection. Administration of anandamide induced significant hyperphagia. Pretreatment with the selective CB1 cannabinoid antagonist SR 141716 (30 μg 0.5 μl−1), 30 min prior to anandamide injection resulted in an attenuation of the anandamide‐induced hyperphagia (P<0.001). This study demonstrates that intrahypothalamic anandamide initiates appetite by stimulation of CB1 receptors, thus providing evidence on the involvement of hypothalamic endocannabinoids in appetite initiation.

British Journal of Pharmacology (2001) 134, 1151–1154; doi:10.1038/sj.bjp.0704379
Prostacyclin receptor‐independent inhibition of phospholipase C activity by non‐prostanoid prostacyclin mimetics
Authors: Chow Kevin B S , Wong Yung H , Wise Helen
Published: January 2005

Chinese hamster ovary (CHO) cells were transiently transfected with the mouse prostacyclin (mIP) receptor to examine IP agonist‐mediated stimulation of [3H]‐cyclic AMP and [3H]‐inositol phosphate production.

The prostacyclin analogues, cicaprost, iloprost, carbacyclin and prostaglandin E1, stimulated adenylyl cyclase activity with EC50 values of 5, 6, 25 and 95 nM, respectively. These IP agonists also stimulated the phospholipase C pathway with 10 – 40 fold lower potency than stimulation of adenylyl cyclase.

The non‐prostanoid prostacyclin mimetics, octimibate, BMY 42393 and BMY 45778, also stimulated adenylyl cyclase activity, with EC50 values of 219, 166 and 398 nM, respectively, but failed to stimulate [3H]‐inositol phosphate production.

Octimibate, BMY 42393 and BMY 45778 inhibited iloprost‐stimulated [3H]‐inositol phosphate production in a non‐competitive manner.

Activation of the endogenously‐expressed P2 purinergic receptor by ATP led to an increase in [3H]‐inositol phosphate production which was inhibited by the non‐prostanoid prostacyclin mimetics in non‐transfected CHO cells. Prostacyclin analogues and other prostanoid receptor ligands failed to inhibit ATP‐stimulated [3H]‐inositol phosphate production.

A comparison between the IP receptor‐specific non‐prostanoid ONO‐1310 and the structurally‐related EP3 receptor‐specific agonist ONO‐AP‐324, indicated that the inhibitory effect of non‐prostanoids was specific for those compounds known to activate IP receptors.

The non‐prostanoid prostacyclin mimetics also inhibited phospholipase C activity when stimulated by constitutively‐active mutant GαqRC, Gα14RC and Gα16QL transiently expressed in CHO cells. These drugs did not inhibit adenylyl cyclase activity when stimulated by the constitutively‐active mutant GαsQL.

These results suggest that non‐prostanoid prostacyclin mimetics can specifically inhibit [3H]‐inositol phosphate production by targeting Gq/11 and/or phospholipase C in CHO cells, and that this effect is independent of IP receptors.

British Journal of Pharmacology (2001) 134, 1375–1384; doi:10.1038/sj.bjp.0704388
A comparison of effects measured with isotonic and isometric recording: I. Concentration‐effect curves for agonists
Authors: Barlow R B , Bond Susan M , Grant Claire , McQueen D S , Yaqoob Zeenat
Published: January 2005

British Journal of Pharmacology (2001) 134, 1596; doi:10.1038/sj.bjp.0704392
Endothelin‐1 increases cholinergic nerve‐mediated contraction of human bronchi via tachykinin synthesis induction
Authors: D'Agostino Bruno , Advenier Charles , Falciani Maddalena , Gallelli Luca , Marrocco Giuseppina , Piegari Elena , Filippelli Amelia , Rossi Francesco
Published: January 2005

In some asthmatics, muscarinic receptor antagonists are effective in limiting bronchoconstrictor response, suggesting an abnormal cholinergic drive in these subjects. There is a growing body of evidences indicating that cholinergic neurotransmission is also enhanced by endothelin‐1 (ET‐1) in rabbit bronchi, mouse trachea and in human isolated airway preparations.

We investigated the role of secondary mediators in ET‐1 induced potentiation of cholinergic nerve‐mediated contraction in human bronchi, in particular the possible role of neuropeptides in this phenomenon.

Bronchial tissues after endothelin treatment were exposed to a standard electrical field stimulation (EFS) (30% of EFS 30Hz)‐induced contraction. In addition, in some experiments, preparations were treated with a tachykinin NK2 receptor antagonist and subsequently exposed to the same protocol. HPLC and RIA were performed on organ bath fluid samples. Moreover, the human bronchi were used for the β‐PPT (preprotachykinin) mRNA extraction and semiquantitative reverse transcription polymerase chain reaction (RT – PCR), prior to and 30 – 40 min following ET‐1 challenge.

The selective tachykinin NK2 receptor antagonist, SR48968, was effective to reduce ET‐1 potentiation of EFS mediated contraction. HPLC or RIA showed significant increased quantities of NKA in organ bath effluents after EFS stimulation in bronchi pretreated with ET‐1. Finally, β‐PPT mRNA level after stimulation of bronchi with ET‐1 was increased about 2 fold respect to control untreated bronchi.

In conclusion, this study demonstrated that, at least in part, the ET‐1 potentiation of cholinergic nerve‐mediated contraction is mediated by tachykinin release, suggesting that in addition to nerves, several type of cells, such as airway smooth muscle cell, may participate to neuropeptide production.

British Journal of Pharmacology (2001) 134, 1447–1454; doi:10.1038/sj.bjp.0704395
Anti‐inflammatory effect of synthetic somatostatin analogues in the rat
Authors: Helyes Zsuzsanna , Pintér Erika , Németh József , Kéri György , Thán Márta , Oroszi Gábor , Horváth Anikó , Szolcsányi János
Published: January 2005

Somatostatin (6.11 nmol kg−1 i.p.) inhibited neurogenic plasma extravasation evoked by 1% mustard oil and non‐neurogenic oedema induced by 5% dextran in the rat skin.

Cyclic synthetic octapeptide (TT‐248 and TT‐250) and heptapeptide (TT‐232) somatostatin analogues proved to be more effective in reducing neurogenic and non‐neurogenic inflammatory reactions but octreotide had no influence on either neurogenic or non‐neurogenic inflammation.

TT‐232 administered i.p. or i.v. (1.06 – 42.40 nmol kg−1) inhibited in a dose‐dependent manner the plasma extravasation evoked by mustard oil in the rat's paw. Neither diclofenac (15.78 – 315.60 μmol kg−1) nor the selective COX‐2 inhibitor meloxicam (2.95 – 569.38 μmol kg−1) attenuated the mustard oil‐induced neurogenic plasma extravasation.

TT‐232, diclofenac and meloxicam dose‐dependently diminished non‐neurogenic dextran‐oedema of the paw the ED35 values were 1.73 nmol kg−1 for TT‐232 and 34.37 μmol kg−1 for diclofenac.

TT‐232 inhibited in the dose range of 1.06 – 21.21 nmol kg−1 the bradykinin‐induced plasma extravasation in the skin of the chronically denervated paw.

Mustard oil‐induced cutaneous plasma extravasation was dose‐dependently diminished by s.c. TT‐232 1, 2, 4, 6 or 16 h after the treatment. TT‐232 (2×106, 2×212 and 2×530 nmol kg−1 per day s.c. for 18 days) caused dose‐dependent inhibition of chronic Freund adjuvant‐induced arthritis during the experimental period.

TT‐232 (200 and 500 nM) inhibited the release of SP, CGRP and somatostatin from the rat isolated trachea induced by electrical field stimulation (40 V, 0.1 ms, 10 Hz, 120 s) or by capsaicin (10−7 M), but did not influence the basal, non‐stimulated peptide release.

It is concluded that somatostatin analogues without endocrine functions as TT‐232 are promising compounds with a novel site of action for inhibition of non‐neurogenic and neurogenic inflammatory processes.

British Journal of Pharmacology (2001) 134, 1571–1579; doi:10.1038/sj.bjp.0704396
Saint John's wort: An in vitro analysis of P‐glycoprotein induction due to extended exposure
Authors: Perloff Michael D , Von Moltke Lisa L , Störmer Elke , Shader Richard I , Greenblatt David J
Published: January 2005

Chronic use of Saint John's wort (SJW) has been shown to lower the bioavailability for a variety of co‐administered drugs including indinavir, cyclosporin, and digoxin. Decreases in intestinal absorption through induction of the multidrug resistance transporter, P‐glycoprotein (P‐gp), may explain decreased bioavailability.

The present study characterized the response of P‐gp to chronic and acute exposure of SJW and hypericin (HYP, a presumed active moiety within SJW) in an in vitro system. Experiments were performed with 3 to 300 μg ml−1 of methanol‐extracted SJW and 0.03 to 3 μM HYP, representing low to high estimates of intestinal concentrations.

In induction experiments, LS‐180 intestinal carcinoma cells were exposed for 3 days to SJW, HYP, vehicle or a positive control (ritonavir). P‐gp was quantified using Western blot analysis. P‐gp expression was strongly induced by SJW (400% increase at 300 μg ml−1) and by HYP (700% at 3 μM) in a dose‐dependent fashion. Cells chronically treated with SJW had decreased accumulation of rhodamine 123, a P‐gp substrate, that was reversed with acute verapamil, a P‐gp inhibitor. Fluorescence microscopy of intact cells validated these findings. In Caco‐2 cell monolayers, SJW and HYP caused moderate inhibition of P‐gp‐attributed transport at the maximum concentrations tested.

SJW and HYP significantly induced P‐gp expression at low, clinically relevant concentrations. Similar effects occurring in vivo may explain the decreased bioavailability of P‐gp substrate drugs when co‐administered with SJW.

British Journal of Pharmacology (2001) 134, 1601–1608; doi:10.1038/sj.bjp.0704399
Blood‐brain barrier transport and brain distribution of morphine‐6‐glucuronide in relation to the antinociceptive effect in rats – pharmacokinetic/pharmacodynamic modelling
Authors: Bouw M René , Xie Rujia , Tunblad Karin , Hammarlund‐Udenaes Margareta
Published: January 2005

The objective of this study was to investigate the contribution of the blood‐brain barrier (BBB) transport to the delay in antinociceptive effect of morphine‐6‐glucuronide (M6G), and to study the equilibration of M6G in vivo across the BBB with microdialysis measuring unbound concentrations.

On two consecutive days, rats received an exponential infusion of M6G for 4 h aiming at a target concentration of 3000 ng ml−1 (6.5 μM) in blood. Concentrations of unbound M6G were determined in brain extracellular fluid (ECF) and venous blood using microdialysis and in arterial blood by regular sampling. MD probes were calibrated in vivo using retrodialysis by drug prior to drug administration.

The half‐life of M6G was 23±5 min in arterial blood, 26±10 min in venous blood and 58±17 min in brain ECF (P<0.05; brain vs blood). The BBB equilibration, expressed as the unbound steady‐state concentration ratio, was 0.22±0.09, indicating active efflux in the BBB transport of M6G. A two‐compartment model best described the brain distribution of M6G. The unbound volume of distribution was 0.20±0.02 ml g brain−1. The concentration‐antinociceptive effect relationships exhibited a clear hysteresis, resulting in an effect delay half‐life of 103 min in relation to blood concentrations and a remaining effect delay half‐life of 53 min in relation to brain ECF concentrations.

Half the effect delay of M6G can be explained by transport across the BBB, suggesting that the remaining effect delay of 53 min is a result of drug distribution within the brain tissue or rate‐limiting mechanisms at the receptor level.

British Journal of Pharmacology (2001) 134, 1796–1804; doi:10.1038/sj.bjp.0704406
The involvement of L‐type Ca2+ channels in the relaxant effects of the ATP‐sensitive K+ channel opener ZD6169 on pig urethral smooth muscle
Authors: Teramoto Noriyoshi , Yunoki Takakazu , Ikawa Shigeoki , Takano Naruaki , Tanaka Kiyoshi , Seki Narihito , Naito Seiji , Ito Yushi
Published: January 2005

The effects of ZD6169, a novel ATP‐sensitive K+ channel (KATP channel) opener, were investigated on membrane currents in isolated myocytes using patch‐clamp techniques. Tension measurement was also performed to study the effects of ZD6169 on the resting tone of pig urethral smooth muscle.

Levcromakalim was more potent than ZD6169 in lowering the resting urethral tone. Relaxation induced by low concentrations of ZD6169 (3 μM) was completely suppressed by additional application of glibenclamide (1 μM). In contrast, glibenclamide (1 – 10 μM) only partially inhibited the relaxation induced by higher concentrations of ZD6169 (10 μM).

Bay K8644 (1 μM) reduced the maximum relaxation produced by ZD6169 (10 μM).

In whole‐cell configuration, ZD6169 suppressed the peak amplitude of voltage‐dependent Ba2+ currents in a concentration‐ and voltage‐dependent manner, and at 100 μM, shifted the steady‐state inactivation curve of the voltage‐dependent Ba2+ currents to the left at a holding potential of −90 mV.

In cell‐attached configuration, open probability of unitary voltage‐dependent Ba2+ channels (27 pS, 90 mM Ba2+) was inhibited by 100 μM ZD6169 and by 10 μM nifedipine.

Reverse transcriptase‐polymerase chain reaction (RT – PCR) analysis revealed the presence of the transcript of the α1C subunit of L‐type Ca2+ channels in pig urethra.

These results demonstrate that ZD6169 causes urethral relaxation through two distinct mechanisms, activation of KATP channels at lower concentrations and inhibition of voltage‐dependent Ca2+ channels at higher concentrations (about 10 μM).

British Journal of Pharmacology (2001) 134, 1505–1515; doi:10.1038/sj.bjp.0704408
Orexin A and B evoke noradrenaline release from rat cerebrocortical slices
Authors: Hirota Kazuyoshi , Kushikata Tetsuya , Kudo Mihoko , Kudo Tsuyoshi , Lambert David G , Matsuki Akitomo
Published: January 2005

Orexin A and B, recently identified in the rat hypothalamus are endogenous neuropeptide agonists for the G‐protein coupled orexin‐1 (OX1) and orexin‐2 (OX2) receptors.

In the present study, we have examined the effects of orexin A, B and raised extracellular K+ on noradrenaline release from the rat cerebrocortical slice. We have compared this with other sleep – wake‐related (excitatory) neurotransmitters; dopamine, glutamate, serotonin and histamine.

Neurotransmitter release studies were performed in rat cerebrocortical slices incubated in modified Krebs buffer (with and without Ca2++EGTA 1 mM) with various concentrations of orexin A, B and K+ for various times.

Orexin A and B‐evoked (10−7 M) noradrenaline release was time‐dependent reaching a maximum some 10 min after stimulation. K+ (40 mM) evoked release was also time dependent but reached a maximum after 6 min. Orexin A, B and K+ stimulation of release was concentration dependent with pEC50 and Emax (% of basal) values of 8.74±0.32 (1.8 nM) and 263±14% and 8.61±0.38 (2.4 nM) and 173±7% and 1.43±0.02 (37 mM) and 1430±70%, respectively. Orexin‐evoked release was partially extracellular Ca2+ dependent.

Of the other transmitters studied there was a weak orexin A and B stimulation of glutamate release. In contrast K+ evoked dopamine, glutamate, histamine and serotonin release with pEC50 and Emax (% of basal) values of 1.47±0.05 (34 mM) and 3430±410%, 1.38±0.04 (42 mM) and 1240±50%, 1.47±0.02 (34 mM) and 480±10% and 1.40±0.05 (40 mM) and 560±60% respectively.

We conclude that the neuropeptides orexin A and B evoke noradrenaline release from rat cerebrocortical slices.

British Journal of Pharmacology (2001) 134, 1461–1466; doi:10.1038/sj.bjp.0704409
Disruption of antigen‐induced airway inflammation and airway hyper‐responsiveness in low affinity neurotrophin receptor p75 gene deficient mice
Authors: Tokuoka Shota , Takahashi Yoshimasa , Masuda Taisei , Tanaka Hiroyuki , Furukawa Shoei , Nagai Hiroichi
Published: January 2005

Recently, much attention has been paid to the relationship between the nervous and immune systems. The present study was conducted to clarify the role of neurotrophin low affinity receptor (p75N) in allergic airway inflammation and hyper‐responsiveness (AHR) in mice by employing p75N gene deficient mice.

Mice were immunized twice by intraperitoneal injections of ovalbumin (OA) at intervals of 12 days. OA was inhaled 10 days after the secondary immunization and repeated three times at 4 days interval. Twenty‐four hours after the last inhalation, airway responsiveness to acetylcholine was measured and bronchoalveolar lavage fluid (BALF) was obtained for examining the number of inflammatory cells and the level of cytokines. Serum immunoglobulin was measured as a marker of systemic immune response before the final inhalation.

In wild‐type mice, repeated antigen provocation resulted in airway eosinophilia, AHR and elevations in serum IgE and interleukin (IL)‐4 and −5 in BALF. In p75N gene deficient mice, none of the above parameters was observed after antigen provocation. The antigen‐induced production of interferon (IFN)‐γ and nerve growth factor (NGF) were not altered by depletion of p75N gene.

The present findings suggest that p75 gene deficiency disrupt an allergic airway inflammation and AHR in mice by interfering type 2 helper T (Th2) cell responses.

British Journal of Pharmacology (2001) 134, 1580–1586; doi:10.1038/sj.bjp.0704411
Effects of sepsis on mast cells in rat dura mater: influence of L‐NAME and VIP
Authors: Tore F , Reynier‐Rebuffel A M , Tuncel N , Callebert J , Aubineau P
Published: January 2005

The influence of lipopolysaccharide (LPS)‐induced sepsis on the various mast cell phenotypes of rat dura mater were examined both by immunohistochemical and biochemical methods.

Three different populations of mast cells were identified in control rats: connective tissue type mast cells (CTMC) which contain rat mast cell protease1 (RMCP1), histamine, serotonin and heparin, mucosal type mast cells (MMC) which contain RMCP2, histamine and serotonin, and intermediate type which contains both RMCP1 and RMCP2 and probably various proportions of amines and heparin.

LPS (25 mg kg−1 i.p.) caused changes in the proportions of the various types of mast cells. The number of MMC and intermediate type mast cells significantly increased and the number of mast cells immunopositive for both heparin and serotonin significantly decreased. Biochemical analysis showed that the histamine concentration of dura increased while its serotonin concentration decreased.

While vasoactive intestinal peptide (VIP) (25 ng kg−1 i.p.) appears to potentiate LPS effects on dura mater mast cells, non‐selective inhibition of nitric oxide (NO) synthase by Ng‐nitro‐L‐arginine methyl ester (L‐NAME) (30 mg kg−1 i.p.) did not influence sepsis‐induced mast cell changes.

These findings suggest that mast cells of dura mater may play a role in brain protection during sepsis.

British Journal of Pharmacology (2001) 134, 1367–1374; doi:10.1038/sj.bjp.0704412
Activation of endothelial cell IKCa with 1‐ethyl‐2‐benzimidazolinone evokes smooth muscle hyperpolarization in rat isolated mesenteric artery
Authors: Walker S D , Dora K A , Ings N T , Crane G J , Garland C J
Published: January 2005

In rat small mesenteric arteries contracted with phenylephrine, 1‐ethyl‐2‐benzimidazolinone (1‐EBIO; 3 – 300 μM) evoked concentration‐dependent relaxation that, above 100 μM, was associated with smooth muscle hyperpolarization.

1‐EBIO‐evoked hyperpolarization (maximum 22.1±3.6 mV with 300 μM, n=4) was endothelium‐dependent and inhibited by charybdotoxin (ChTX 100 nM; n=4) but not iberiotoxin (IbTX 100 nM; n=4).

In endothelium‐intact arteries, smooth muscle relaxation to 1‐EBIO was not altered by either of the potassium channel blockers ChTX (100 nM; n=7), or IbTX (100 nM; n=4), or raised extracellular K+ (25 mM). Removal of the endothelium shifted the relaxation curve to the right but did not reduce the maximum relaxation.

In freshly isolated mesenteric endothelial cells, 1‐EBIO (600 μM) evoked a ChTX‐sensitive outward K‐current. In contrast, 1‐EBIO had no effect on smooth muscle cell conductance whereas NS 1619 (33 μM) stimulated an outward current while having no effect on the endothelial cells.

These data show that with concentrations greater than 100 μM, 1‐EBIO selectively activates outward current in endothelial cells, which presumably underlies the smooth muscle hyperpolarization and a component of the relaxation. Sensitivity to block with charybdotoxin but not iberiotoxin indicates this current is due to activation of IKCa. However, 1‐EBIO can also relax the smooth muscle by an undefined mechanism, independent of any change in membrane potential.

British Journal of Pharmacology (2001) 134, 1548–1554; doi:10.1038/sj.bjp.0704415
Thromboxane receptor density is increased in human cardiovascular disease with evidence for inhibition at therapeutic concentrations by the AT1 receptor antagonist losartan
Authors: Katugampola Sidath D , Davenport Anthony P
Published: January 2005

The aim of this study was to establish how thromboxane receptors (TP) respond to the increase in levels of plasma thromboxane observed in both cardiac (cardiomyopathy, ischaemic heart disease and pulmonary hypertension) and vascular disease (atherosclerosis of coronary artery disease and accelerated atherosclerosis of saphenous vein grafts).

The agonist radioligand [125I]‐BOP, bound rapidly to TP receptors in normal human cardiovascular tissue, displaying high affinity in left ventricle (KD 0.23±0.06 nM, Bmax 28.4±5.7 fmol mg−1 protein) and reversibility with a t1/2 of 10 min (n=five individuals±s.e.mean).

In the heart, TP receptor density in the right ventricle of primary pulmonary hypertensive patients were significantly increased (66.6±6 fmol mg−1 protein) compared to non‐diseased right ventricle (37.9±4.1 fmol mg−1 protein, n=six individuals±s.e.mean, P<0.05).

In diseased vessels, TP receptor densities were significantly increased (3 fold in the intimal layer) in atherosclerotic coronary arteries, saphenous vein grafts with severe intimal thickening (n=8 – 12 individuals, P<0.05) and aortic tissue (n=5 – 6 individuals, P<0.05), compared with normal vessels.

Losartan, tested at therapeutic doses, competed for [125I]‐BOP binding to human vascular tissue, suggesting that some of the anti‐hypertensive effects of this AT1 receptor antagonist could also be mediated by blocking human TP receptors.

The differential distribution of TP receptors in the human cardiovascular system and the alteration of receptor density, accompanying the increase in endogenous thromboxane levels in cardiovascular disease, suggest that TP receptors represent a significant target for therapeutic interventions and highlights the importance for the development of novel selective antagonist for use in humans.

British Journal of Pharmacology (2001) 134, 1385–1392; doi:10.1038/sj.bjp.0704416
Inhibition of immune‐complex mediated dermal inflammation in rats following either oral or topical administration of a small molecule C5a receptor antagonist
Authors: Strachan Anna J , Shiels Ian A , Reid Robert C , Fairlie David P , Taylor Stephen M
Published: January 2005

Initiation of a peritoneal Arthus reaction by deposition of immune‐complexes results in vascular leakage, polymorphonuclear leukocyte (PMN) infiltration, and tumour necrosis factor α (TNFα) and interleukin‐6 (IL‐6) production. We now demonstrate in rats that oral administration of the C5a receptor antagonist AcPhe[Orn‐Pro‐D‐Cyclohexylalanine‐Trp‐Arg] (AcF‐[OPdChaWR]; 1 – 10 mg kg−1 30 min prior to immune‐complex deposition) inhibits these inflammatory markers in the peritoneal Arthus reaction.

Initiation of a dermal Arthus reaction resulted in a significant increase in vascular leakage, PMN infiltration, systemic production of TNFα and pathological changes in the dermis.

Pretreatment of rats with AcF‐[OPdChaWR] either intravenously (1 mg kg−1 10 min prior to immune‐complex deposition) or orally (1 – 10 mg kg−1 30 min prior to immune‐complex deposition) significantly inhibited immune‐complex mediated dermal vascular leakage and systemic cytokine production. Topical pretreatment with AcF‐[OPdChaWR] (400 μg site−1 in 10% dimethyl sulphoxide 10 min prior to immune‐complex deposition) also inhibited vascular leakage, as well as histopathological changes associated with a dermal Arthus reaction.

Oral administration of 3 mg kg−1 AcF‐[OPdChaWR] resulted in the appearance of the drug in plasma within 5 min, with peak blood levels ∼0.3 μM reached within 20 min. The plasma elimination half‐life was ∼70 min. The oral activity and bioavailability of AcF‐[OPdChaWR], its activity when applied topically to the skin, suggest that small molecule C5a receptor antagonists may have therapeutic utility in dermal inflammatory disorders involving complement activation.

This is the first demonstration for either an orally or topically active C5a receptor antagonist, and suggests that small molecule C5a antagonists may have therapeutic utility when given by multiple routes of application.

British Journal of Pharmacology (2001) 134, 1778–1786; doi:10.1038/sj.bjp.0704417
ECL‐cell histamine mobilization in conscious rats: effects of locally applied regulatory peptides, candidate neurotransmitters and inflammatory mediators
Authors: Norlén P , Bernsand M , Konagaya T , Håkanson R
Published: January 2005

The ECL cells control gastric acid secretion by mobilizing histamine in response to circulating gastrin. In addition, the ECL cells are thought to operate under nervous control and to be influenced by local inflammatory processes.

The purpose of the present study was to monitor histamine mobilization from ECL cells in conscious rats in response to locally applied regulatory peptides, candidate neurotransmitters and inflammatory mediators.

Microdialysis probes were implanted in the submucosa of the acid‐producing part of the rat stomach. Three days later, the agents to be tested were administeredviathe microdialysis probe and their effects on basal (48 h fast) and stimulated (intravenous infusion of gastrin‐17, 3 nmol kg−1 h−1) mobilization of ECL‐cell histamine was monitored by continuous measurement of histamine in the perfusate (radioimmunoassay).

Locally administered gastrin‐17 and sulfated cholecystokinin‐8 mobilized histamine as did pituitary adenylate cyclase‐activating peptide‐27, vasoactive intestinal peptide, peptide YY, met‐enkephalin, endothelin and noradrenaline, adrenaline and isoprenaline.

While gastrin, sulfated‐cholecystokinin‐8, met‐enkephalin and isoprenaline induced a sustained elevation of the submucosal histamine concentration, endothelin, peptide YY, pituitary adenylate cyclase activating peptide, vasoactive intestinal peptide, noradrenaline and adrenaline induced a transient elevation.

Calcitonin gene‐related peptide, galanin, somatostatin and the prostanoid misoprostol inhibited gastrin‐stimulated histamine mobilization.

The gut hormones neurotensin and secretin and the neuropeptides gastrin‐releasing peptide, neuropeptide Y and substance P failed to affect ECL‐cell histamine mobilization, while motilin and neuromedin U‐25 had weak stimulatory effects. Also acetylcholine, carbachol, serotonin and the amino acid neurotransmitters aspartate, γ‐aminobutyric acid, glutamate and glycine were inactive or weakly active as was bradykinin.

In summary, a range of circulating hormones, local hormones, catecholamines, neuropeptides and inflammatory mediators participate in controlling the activity of rat stomach ECL cellsin situ.

British Journal of Pharmacology(2001)134, 1767–1777; doi:10.1038/sj.bjp.0704419
Analgesic activity of a novel use‐dependent sodium channel blocker, crobenetine, in mono‐arthritic rats
Authors: Laird J M A , Carter A J , Grauert M , Cervero F
Published: January 2005

Although sodium channel blockers are effective analgesics in neuropathic pain, their effectiveness in inflammatory pain has been little studied. Sodium channels are substantially up‐regulated in inflamed tissue, which suggests they play a role in maintenance of chronic inflammatory pain. We have examined the effects of sodium channel blockers on mobility, joint hyperalgesia and inflammation induced by complete Freund's adjuvant injected in one ankle joint of adult rats. The clinically effective sodium channel blocker, mexiletine, was compared with crobenetine (BIII 890 CL), a new, highly use‐dependent sodium channel blocker.

Rats were treated for 5 days, starting on the day of induction of arthritis and were tested daily for joint hyperalgesia, hind limb posture and mobility. At post‐mortem, joint stiffness and oedema were assessed. Dose response curves were constructed for each test compound (3 – 30 mg kg day−1). Control groups were treated with vehicle or with the non‐steroidal anti‐inflammatory drug, meloxicam (4 mg kg day−1 i.p.).

Both sodium channel blockers produced dose dependent and significant reversal of mechanical joint hyperalgesia and impaired mobility with an ID50 of 15.5±1.1 mg kg day−1 for crobenetine and 18.1±1.2 mg kg day−1 for mexiletine. Neither compound affected the responses of the contralateral non‐inflamed joint, nor had any effect on swelling and stiffness of the inflamed joint.

We conclude that sodium channel blockers are analgesic and anti‐hyperalgesic in this model of arthritis. These data suggest that up regulation of sodium channel expression in primary afferent neurones may play an important role in the pain and hyperalgesia induced by joint inflammation.

British Journal of Pharmacology (2001) 134, 1742–1748; doi:10.1038/sj.bjp.0704428
trans‐4‐Amino‐2‐methylbut‐2‐enoic acid (2‐MeTACA) and (±)‐trans‐2‐aminomethylcyclopropanecarboxylic acid ((±)‐TAMP) can differentiate rat ρ3 from human ρ1 and ρ2 recombinant GABAC receptors
Authors: Vien Jimmy , Duke Rujee K , Mewett Kenneth N , Johnston Graham A R , Shingai Ryuzo , Chebib Mary
Published: January 2005

This study investigated the effects of a number of GABA analogues on rat ρ3 GABAC receptors expressed in Xenopus oocytes using 2‐electrode voltage clamp methods.

The potency order of agonists was muscimol (EC50=1.9±0.1 μM) (+)‐trans‐3‐aminocyclopentanecarboxylic acids ((+)‐TACP; EC50=2.7±0.9 μM) trans‐4‐aminocrotonic acid (TACA; EC50=3.8±0.3 μM) GABA (EC50=4.0±0.3 μM) > thiomuscimol (EC50=24.8±2.6 μM) > (±)‐cis‐2‐aminomethylcyclopropane‐carboxylic acid ((±)‐CAMP; EC50=52.6±8.7 μM) > cis‐4‐aminocrotonic acid (CACA; EC50=139.4±5.2 μM).

The potency order of antagonists was (±)‐trans‐2‐aminomethylcyclopropanecarboxylic acid ((±)‐TAMP; KB=4.8±1.8 μM) (1,2,5,6‐tetrahydropyridin‐4‐yl)methylphosphinic acid (TPMPA; KB=4.8±0.8 μM) > (piperidin‐4‐yl)methylphosphinic acid (P4MPA; KB=10.2±2.3 μM) 4,5,6,7‐tetrahydroisoxazolo[5,4‐c]pyridin‐3‐ol (THIP; KB=10.2±0.3  μM) imidazole‐4‐acetic acid (I4AA; KB=12.6±2.7 μM) > 3‐aminopropylphosphonic acid (3‐APA; KB=35.8±13.5 μM).

trans‐4‐Amino‐2‐methylbut‐2‐enoic acid (2‐MeTACA; 300 μM) had no effect as an agonist or an antagonist indicating that the C2 methyl substituent is sterically interacting with the ligand‐binding site of rat ρ3 GABAC receptors.

2‐MeTACA affects ρ1 and ρ2 but not ρ3 GABAC receptors. In contrast, (±)‐TAMP is a partial agonist at ρ1 and ρ2 GABAC receptors, while at rat ρ3 GABAC receptors it is an antagonist. Thus, 2‐MeTACA and (±)‐TAMP could be important pharmacological tools because they may functionally differentiate between ρ1, ρ2 and ρ3 GABAC receptors in vitro.

British Journal of Pharmacology (2002) 135, 883–890; doi:10.1038/sj.bjp.0704432
Activation of central melanocortin receptors by MT‐II increases cavernosal pressure in rabbits by the neuronal release of NO
Authors: Vemulapalli Rao , Kurowski Stan , Salisbury Brian , Parker Eric , Davis Harry
Published: January 2005

Melanotan‐II had been reported to cause penile erections in men with erectile dysfunction. In the present study, we investigated the mechanisms by which systemic administration of MT‐II increases intracavernosal pressure in anaesthetized rabbits.

MT‐II (10 μM) had no effect on electrical field stimulation‐evoked relaxations of rabbit corpus cavernosal strips in vitro.

Intravenous injection of MT‐II (66 and 133 μg kg−1 elicited dose‐related increases in cavernosal pressure. SHU 9119 (3 μg kg−1, i.v.), a non‐selective antagonist of MC3 and MC4 receptors did not significantly affect either cavernosal pressure or systemic blood pressure but abolished the MT‐II‐induced increases in cavernosal pressure. SHU 9119 also inhibited the depressor response produced by MT‐II.

Intracavernosal injection 100 μl of the cocktail containing phentolamine mesylate (1 mg ml−1), papaverine (20 mg ml−1) and PGE1 (20 μg ml−1) increased the cavernosal pressure by about 4 fold.

The role of NO‐cyclic GMP dependent pathway to MT‐II‐induced increases in cavernosal pressure was investigated by bilateral transection of the pudendal nerves and by inhibition of NO synthase with L‐NAME (20 mg kg−1, i.v. over 30 min). Ablation of the pudendal nerves or pretreatment with L‐NAME abolished the MT‐II‐induced increases in intracavernosal pressure in anaesthetized rabbits.

The data suggest that activation of central melanocortin receptors by MT‐II increases cavernosal pressure by the neuronal release of NO.

British Journal of Pharmacology (2001) 134, 1705–1710; doi:10.1038/sj.bjp.0704437
Cardioselectivity of the sulphonylurea HMR 1098: studies on native and recombinant cardiac and pancreatic KATP channels
Authors: Manning Fox Jocelyn E , Kanji Hussein D , French Robert J , Light Peter E
Published: January 2005

In this study we investigated the effects of the putative cardioselective sulphonylurea derivative HMR 1098 on ATP‐sensitive potassium (KATP) channels from cardiac ventricular myocytes, the INS‐1 β‐cell line and from recombinant KATP channels composed of SUR2A/Kir6.2, SUR1/Kir6.2, SUR1/Kir6.1 an Kir6.2,ΔC26. Recombinant channels were expressed in tsA201 or COS‐1 cells.

The effects of HMR 1098 on single channel and whole‐cell currents were recorded using the patch‐clamp technique.

At the single channel level, using excised inside‐out membrane patches, HMR 1098 inhibited KATP channels from ventricular cells and INS‐1 cells with IC50s of 0.88 and 720 μM respectively. Similar results to those in cardiac cells were obtained using recombinant SUR2A/Kir6.2 KATP channels. HMR 1098 inhibition of SUR2A/Kir6.2 KATP channels was unaffected by the presence of internal ADP.

In whole‐cell recordings, HMR 1098 inhibited SUR2A/Kir6.2 and SUR1/Kir6.2 currents with IC50s of 2.1 and 860 μM respectively. HMR 1098 was without effect on currents either from the Kir6.2,ΔC26 truncation mutant or from Kir2.1.

Our results demonstrate that HMR 1098 is a selective inhibitor of cardiac KATP channels, showing a 400–800‐fold selectivity over β‐cell KATP channels. The non‐aromatic substitutions in the sulphonylurea moiety greatly increase the cardioselectivity of this compound while reducing the overall blocking potency of this sulphonylurea derivative.

British Journal of Pharmacology (2002) 135, 480–488; doi:10.1038/sj.bjp.0704455
Role of tachykinin NK receptors on the local and remote injuries following ischaemia and reperfusion of the superior mesenteric artery in the rat
Authors: Souza Danielle G , Mendonça Vanessa A , Castro Maria Salete de A , Poole Steve , Teixeira Mauro M
Published: January 2005

Neuropeptides acting on tachykinin NK receptors play an important role in the amplification of inflammatory responses. We have assessed the effects of tachykinin NK receptor blockade on the injuries following intestinal ischaemia and reperfusion (I/R) in rats.

The tachykinin NK1 receptor antagonist SR140333 dose‐dependently (0.05 to 0.5 mg kg−1) suppressed the local (intestine) and remote (lung) increases in vascular permeability and neutrophil recruitment following mild I/R injury. A structurally‐distinct NK1 receptor antagonist, CP99,994, but not tachykinin NK2 or NK3 receptor antagonists also suppressed mild I/R injury.

Neonatal pretreatment with capsaicin effectively depleted sensory neurons and abrogated the injuries following mild I/R.

Treatment with SR140333 (0.5 mg kg−1) significantly reversed severe reperfusion‐induced local and remote increases in vascular permeability, neutrophil recruitment, intestinal haemorrhage and blood neutropaenia, but did not prevent the lethality associated with severe I/R.

Post‐ischaemic treatment with SR140333 significantly inhibited the elevations of TNF‐α in the intestine and lung, but not serum, following severe I/R. The increase in the concentrations of IL‐10 in the lung and serum were also suppressed.

Post‐ischaemic blockade of tachykinin NK1 receptors markedly inhibited the local and remote injuries, but not lethality, following reperfusion of the SMA in rats. Neuropeptides, possibly substance P, released from sensory nerves appear to account for the activation of these tachykinin NK1 receptors. Antagonists of the tachykinin NK1 receptor may be useful adjuncts in the treatment of the injuries which occur following reperfusion of an ischaemic vascular territory.

British Journal of Pharmacology (2002) 135, 303–312; doi:10.1038/sj.bjp.0704464
Contribution of cytochrome P450 metabolites to bradykinin‐induced vasodilation in endothelial NO synthase deficient mouse hearts
Authors: Ding Zhaoping , Gödecke Axel , Schrader Jürgen
Published: January 2005

We have characterized the contribution of endothelial nitric oxide synthase (eNOS), cyclo‐oxygenase (COX) and cytochrome P450 (CYP450) to the bradykinin (BK)‐ induced vasodilation in isolated hearts from wildtype (WT) and eNOS deficient mice (eNOS−/−).

The endothelium‐dependent vasodilation by bradykinin (BK, 1 μM) was significantly lower in eNOS−/− hearts than that in WT hearts (+247% and +325% of basal flow, respectively), while there was no difference in the endothelium‐independent vasodilation by adenosine.

In WT hearts, the BK‐induced vasodilation was markedly attenuated following inhibition of NOS with ETU (10 μM) but not after COX inhibition with diclofenac (3 μM) (P<0.01). In line with this finding, Bk did not increase the cardiac prostacyclin release as measured by ELISA for 6‐keto‐PGF1α in the coronary venous effluent. In eNOS−/− hearts, the flow response to BK was insensitive to both NOS and COX inhibition.

The NOS/COX‐independent vasodilatory factor which remained under L‐NMMA+DF application was almost completely eliminated by either clotrimazole (3 μM), miconazole (0.5 μM) or 17‐ODYA (1 μM), suggesting that it was a metabolite of CPY450 enzymes. Sulfaphenazole (10 μM), a CYP450 2C inhibitor, exerted only a minimal inhibitory effect.

In eNOS−/− hearts the effect of CYP450 inhibitors on the BK response was significantly more pronounced than in WT hearts, indicating an enhanced contribution of CYP450 enzymes.

These findings suggest that in isolated mouse hearts the BK‐induced vasodilation is mediated by NO and CYP450 metabolites but not by prostaglandins. The CYP450 dependent vasodilator was was functionally up‐regulated in eNOS−/− hearts and thus likely to compensate for the loss of eNOS in the coronary circulation.

British Journal of Pharmacology (2002) 135, 631–638; doi:10.1038/sj.bjp.0704472
Different glucocorticoids vary in their genomic and non‐genomic mechanism of action in A549 cells
Authors: Croxtall Jamie D , Van Hal Peter Th W , Choudhury Qam , Gilroy Derek W , Flower Rod J
Published: January 2005

We have examined the effects of 12 glucocorticoids as inhibitors of A549 cell growth.

Other than cortisone and prednisone, all the glucocorticoids inhibited cell growth and this was strongly correlated (r=0.91) with inhibition of prostaglandin (PG)E2 formation.

The molecular mechanism by which the active steroids prevented PGE2 synthesis was examined and three groups were identified. Group A drugs did not inhibit arachidonic acid release but inhibited the induction of COX2. Group B drugs were not able to inhibit the induction of COX2 but inhibited arachidonic acid release through suppression of cPLA2 activation. Group C drugs were apparently able to bring about both effects.

The inhibitory actions of all steroids was dependent upon glucocorticoid receptor occupation since RU486 reversed their effects. However, group A acted through the NF‐κB pathway to inhibit COX2 as the response was blocked by the inhibitor geldanamycin which prevents dissociation of GR and the effect was blocked by APDC, the NF‐κB inhibitor. On the other hand, the group B drugs were not inhibited by NF‐κB inhibitors or geldanamycin but their effect was abolished by the src inhibitor PP2. Group C drugs depended on both pathways.

In terms of PGE2 generation, there is clear evidence of two entirely separate mechanisms of glucocorticoid action, one of which correlates with NF‐κB mediated genomic actions whilst the other, depends upon rapid effects on a cell signalling system which does not require dissociation of GR. The implications for these findings are discussed.

British Journal of Pharmacology (2002) 135, 511–519; doi:10.1038/sj.bjp.0704474
Functional characterization of an endogenous Xenopus oocyte adenosine receptor
Authors: Kobayashi Toru , Ikeda Kazutaka , Kumanishi Toshiro
Published: January 2005

To investigate the effects of adenosine on endogenous Xenopus oocyte receptors, we analysed defolliculated oocytes injected with mRNAs for the G protein‐activated inwardly rectifying K+ (GIRK) channels.

In oocytes injected with mRNAs for either GIRK1/GIRK2 or GIRK1/GIRK4 subunits, application of adenosine or ATP reversibly induced inward K+ currents, although ATP was less potent than adenosine. The responses were attenuated by caffeine, a non‐selective adenosine receptor antagonist. Furthermore, in uninjected oocytes from the same donor, adenosine produced no significant current.

The endogenous receptor was activated by two selective A1 adenosine receptor agonists, N6‐cyclopentyladenosine (CPA) and N6‐cyclohexyladenosine (CHA), and antagonized by a selective A1 adenosine receptor antagonist, 1,3‐dipropyl‐8‐cyclopenylxanthine (DPCPX) at moderate nanomolar concentrations, but insensitive to micromolar concentrations of selective A2A and A3 adenosine receptor agonists, 2‐[p‐(2‐carbonyl‐ethyl)‐phenylethylamino]‐5′‐N‐ethylcarboxamidoadenosine (CGS21680) and N6‐(3‐iodobenzyl)‐5′‐(N‐methylcarbamoyl)adenosine (IB‐MECA), respectively. However, the pharmacological characteristics of the receptor were different from those of the cloned Xenopus A1 adenosine receptor and previously proposed adenosine receptors.

The adenosine‐induced GIRK currents were abolished by injection of pertussis toxin and CPA inhibited forskolin‐stimulated cyclic AMP accumulation.

We conclude that an adenosine receptor on the Xenopus oocyte membrane can activate GIRK channels and inhibit adenylyl cyclase via Gi/o proteins. Moreover, our results suggest the existence of an endogenous adenosine receptor with the unique pharmacological characteristics. As the receptor was activated by nanomolar concentrations of adenosine, which is a normal constituent of extracellular fluid, the receptor may be involved in some effects through the Gi/o protein signalling pathways in ovarian physiology.

British Journal of Pharmacology (2002) 135, 313–322; doi:10.1038/sj.bjp.0704475
Nucleotide‐mediated relaxation in guinea‐pig aorta: selective inhibition by MRS2179
Authors: Kaiser Robert A , Buxton Iain L O
Published: January 2005

The vasodilatory effects of nucleotides in the guinea‐pig thoracic aorta were examined to determine the relationship between molecular expression and function of P2Y receptors.

In aortic rings precontracted with norepinephrine, vasodilatory responses to purine nucleotides exhibited a rank‐order of potency of 2‐methylthio‐ATP>ADP>ATP. Responses to UTP, but not UDP suggested a functional role for P2Y4 but not P2Y6 receptors.

Aortic endothelial cells express at least four P2Y receptors; P2Y1, P2Y2, P2Y4 and P2Y6. In primary culture, these cells exhibit desensitizing transient calcium responses characteristic of P2Y1, P2Y2 and P2Y4, but not P2Y6 receptors. UDP had no effect on endothelial cell calcium.

The pyrimidinergic receptor agonist UTP is capable of eliciting robust vasodilation in aortic rings and causing calcium responses in cultured guineapig aortic endothelial cells. These responses are equivalent to the maximum responses observed to ATP and ADP.

Measurement of intracellular calcium release in response to ATP and 2‐methylthio‐ATP were similar, however only the 2‐methylthio‐ATP response was sensitive to the P2Y1 antagonist N6‐methyl‐2′‐deoxyadenosine‐3′,5′‐bisphosphate (MRS2179). In aortic rings, vasodilatory responses to 2‐methylthio‐ATP, ATP and ADP were all blocked by pre‐incubation of tissues with MRS2179.

MRS2179 pretreatment had no effect of the ability of UTP to cause relaxation of norepinephrine responses in aortic rings or the ability of UTP to cause calcium release in aortic endothelial cells.

We demonstrate robust effects of purine and pyrimidine nucleotides in guineapig aorta and provide functional and biochemical evidence that MRS2179 is a selective P2Y1 antagonist.

British Journal of Pharmacology (2001) 135, 537–545; doi:10.1038/sj.bjp.0704476