Induction of vascular smooth muscle bradykinin B1 receptors in vivo during antigen arthritis.

Antigen arthritis in rabbits was associated with induction of bradykinin B1 receptors in isolated aorta smooth muscle 24 h following intra-articular injection of antigen in sensitized animals. Control tissues developed responsiveness to desArg9-bradykinin or bradykinin during 3 h incubation, but failed to respond to either kinin at the beginning of experiments. Aorta from rabbits 24 h after induction of arthritis not only developed responsiveness to kinins more rapidly than controls, but also responded at the outset of experiments. Antigen arthritis was characterized by acute phase protein synthesis and joint swelling. This is the first demonstration of induction of smooth muscle responsiveness to desArg9-bradykinin during an immune complex disease.     

B1 bradykinin receptors and sensory neurones.

1. The location of the B1 bradykinin receptors involved in inflammatory hyperalgesia was investigated. 2. No specific binding of the B1 bradykinin receptor ligand [3H]-des-Arg10-kallidin was detected in primary cultures of rat dorsal root ganglion neurones, even after treatment with interleukin-1 beta (100 iu ml-1). 3. In dorsal root ganglion neurones, activation of B2 bradykinin receptors stimulated polyphosphoinositidase C. In contrast, B1 bradykinin receptor agonists (des-Arg9-bradykinin up to 10 microM and des-Arg10-kallidin up to 1 microM) failed to activate polyphosphoinositidase C, even in neurones that had been treated with interleukin-1 beta (100 iu ml-1), prostaglandin E2 (1 microM) or prostaglandin I2 (1 microM). 4. Dorsal root ganglion neurones removed from rats (both neonatal and 14 days old) that had been pretreated with inflammatory mediators (Freund's complete adjuvant, or carrageenan) failed to respond to B1 bradykinin receptor selective agonists (des-Arg9-bradykinin up to 10 microM and des-Arg10-kallidin up to 1 microM). 5. Bradykinin (25 nM to 300 nM) evoked ventral root responses when applied to peripheral receptive fields or central terminals of primary afferents in the neonatal rat spinal cord and tail preparation. In contrast, des-Arg9-bradykinin (50 nM to 500 nM) failed to evoke ventral root depolarizations in either control rats or in animals that developed inflammation following ultraviolet irradiation of the tail skin. 6. The results of the present study imply that the B1 bradykinin receptors that contribute to hypersensitivity in models of persistent inflammatory hyperalgesia are located on cells other than sensory neurones where they may be responsible for releasing mediators that sensitize or activate the nociceptors.     

Implication of the bradykinin receptors in antigen-induced pulmonary inflammation in mice

1. The involvement of bradykinin (BK) receptors in the allergic inflammation associated with airway hyper-reactivity (AHR) was evaluated by means of the selective bradykinin B(1) receptor (BKB(1)-R) antagonists R-715 (Ac-Lys-[D-betaNal(7), Ile(8)]desArg(9)-BK) and R-954 (Ac-Orn[Oic(2), alpha-MePhe(5), D-betaNal(7), Ile(8)]desArg(9)-BK) or the selective bradykinin B(2) receptor (BKB(2)-R) antagonist HOE-140 (D-Arg(0)-Hyp(3)-Thi(5)-D-Tic(7)-Oic(8)-BK). Cellular migration and AHR were examined 24 h after the second ovalbumin (OA) challenge. 2. R-715 (10-500 microg kg(-1)) and R-954 (1-100 microg kg(-1)) injected intravenously (i.v.), 5 min prior to aerosol OA challenges, decreased by approximately 50% the induced lung eosinophilia in OA-sensitized mice but did not reduce AHR. 3. HOE-140 (1 microg kg(-1)) administered in the same manner, decreased mononuclear cell and eosinophil infiltration in the bronchoalveolar lavage fluid (BALF) of OA-sensitized mice. Moreover, treatment of OA-sensitized mice with HOE-140 (100 microg kg(-1)) completely abolished the AHR to carbachol. 4. The BKB(1)-R agonist desArg(9)-BK (DBK; 10-1000 microg kg(-1)) administered intratrachealy to normal mice had no effect on the basal cell counts recovered in BALF nor on the plasma extravasation, while the BKB(2)-R selective agonist BK (20 microg kg(-1)) stimulated mononuclear cell migration, neutrophilia and plasma extravasation in normal mouse lungs. Such effects were inhibited by HOE-140 (10 microg kg(-1)). 5. Our results suggest that the airway inflammatory response induced by antigen challenge in mice is mediated by stimulation of both BKB(1)-R and BKB(2)-R.     

Contribution of B(2) receptors for bradykinin in arthus reaction-induced plasma extravasation in wild-type or B(2) transgenic knockout mice

The aim of the present study was to investigate the contribution of bradykinin (BK) B(1) and B(2) receptors in a model of type III hypersensitivity, the reverse passive Arthus reaction (RPA), in wild-type mice and transgenic B(2) knockout littermates. BK (10 microg mouse(-1)) or bovine serum albumin (0.5 mg mouse(-1)) induced a sustained Evans blue extravasation for more than 80 min in naive or rabbit anti-bovine serum albumin-treated mice (RPA model), respectively. The response to the two stimuli was prevented by the B(2) receptor antagonist, HOE-140, but not by [Leu(8)]desArg(9)-BK (B(1) receptor antagonist). In contrast to the wild-type littermates, RPA and bradykinin were unable to trigger an increase in plasma extravasation in B(2) knockout mice. Furthermore, endothelin-1 (5 microg mouse(-1)) and a selective NK-1 receptor agonist [Sar(9),Met (O(2))(11)]-SP (20 microg mouse(-1)), triggered a significant increase in peritoneal plasma extravasation in both wild-type and B(2) knockout animals. A pretreatment with indomethacin (200 microg mouse(-1)) significantly reduced the RPA-induced but not the BK-induced increase in Evans blue extravasation. Furthermore, RPA, but not BK, triggered a significant indomethacin-sensitive increase in peritoneal prostaglandin E(2) content. Our results suggest a pivotal role for B(2) receptors in the mechanism of plasma extravasation which occurs during the reverse passive Arthus reaction in the mouse. Moreover, our results suggest an important contribution of prostanoids in the plasma leakage mechanisms triggered by RPA but not by bradykinin.     

Retinal plasma extravasation in streptozotocin-diabetic rats mediated by kinin B(1) and B(2) receptors

BACKGROUND AND PURPOSE: We investigated whether or not kinin receptors play a role in diabetic blood-retinal barrier breakdown, which is a leading cause of vision loss. EXPERIMENTAL APPROACH: Blood-retinal barrier breakdown was quantified using Evans blue, and expression of kinin B(1) receptor mRNA was measured using quantitative reverse transcrition-PCR. Diabetic rats (streptozotocin (STZ), 65 mg kg(-1)) received a single intraocular injection of bradykinin (BK) or des-Arg(9)-BK, alone, or in combination with antagonists for B(1) (des-Arg(10)-Hoe140, R-715) and/or B(2) (Hoe140) receptors, given intraocularly or intravenously (i.v.). KEY RESULTS: In control rats, BK (0.1-10 nmol) dose-dependently increased plasma extravasation, which was inhibited by Hoe140 (0.2 nmol), whereas des-Arg(9)-BK (0.1 and 1 nmol) was without effect. B(1) receptor mRNA was markedly increased in retinas of diabetic rats, and this was prevented by N-acetyl-L-cysteine (1 g kg(-1) day(-1) for 7 days). Plasma extravasation in retinas of STZ-diabetic rats was higher than in controls and enhanced by des-Arg(9)-BK. Response to des-Arg(9)-BK was inhibited by intraocular or i.v. injection of B(1) receptor antagonists. Diabetes-induced plasma extravasation was inhibited only by a combination of des-Arg(10)-Hoe140 and Hoe 140 (100 nmol kg(-1), i.v. 15 min earlier) or by R-715 (1 micromol kg(-1), i.v.) injected daily for 7 days. CONCLUSIONS AND IMPLICATIONS: Kinin B(1) receptors are upregulated in retinas of STZ-diabetic rats through a mechanism involving oxidative stress. Both kinin B(1) and B(2) receptors contribute to increased plasma extravasation in diabetic retinopathy. Chronic inhibition of both kinin receptors, possibly with antioxidant adjuvants, may be a novel therapeutic strategy for diabetic retinopathy.     

The cardiovascular influence of interleukin-1 beta on the expression of bradykinin B1 and B2 receptors

The cytokine interleukin 1ss (IL-1ss) and the bradykinin receptors 1 (B1R) and 2 (B2R) are known to be upregulated in the ischemic heart. In the present study we investigated whether or not there is a causal link between these entities. Further we investigated whether or not pharmacological inhibition of IL-1ss release affects B1R and B2R regulation as well as left ventricular (LV) function in an in vivo rat model of myocardial infarction (MI). B1R and B2R mRNA levels were determined in cultured rat cardiomyocytes, aortic smooth muscle cells and cardiac fibroblasts (n=6 per group) under basal conditions, and after incubation of IL-1ss (40, 400 and 4000 pg/ml). Also, MI was induced in male Sprague-Dawley rats by ligation of the left descending coronary artery. Rats were treated with the interleukin converting enzyme inhibitor (ICEI) pralnacasan (50 mg/kg/day), or with a placebo. Three weeks after induction of MI, LV function was assessed using a 1.4 Millar TIP-catheter. Cardiac expressions of B1R and B2R mRNA were measured using ribonuclease-protection assays. Under basal conditions, both B1R and B2R were expressed in cardiomyocytes and smooth muscle cells, but not in cardiac fibroblasts. IL-1ss cultivation led only in cardiomyocytes to a significant upregulation of B1R mRNA. To a significant upregulation of B2R mRNA, it did not. In addition, ICEI treatment led in vivo to a significant downregulation of cardiac B1R mRNA, but not of B2R mRNA expression three weeks after induction of MI. Our data suggest that a causal link exists between cardiac IL-1ss content and B1R regulation after MI.     

Specific neurokinin receptors mediate plasma extravasation in the rat knee joint.

1 Plasma extravasation in the rat knee joint was induced by intra-articular injection of neurokinins and specific neurokinin receptor agonists. 2 Pronounced plasma extravasation was produced by substance P (SP, 4-185 microM) and to a lesser extent by neurokinin-B (NKB, 83-413 microM), whereas neurokinin-A (NKA, 88-440 microM) and calcitonin gene-related peptide (CGRP, 26-130 microM) had no significant effect. 3 The specific neurokinin1 receptor agonist [Sar9, Met(O2)11]-substance P (NK1 agonist) in doses of 0.4-70 microM appeared to be more potent than SP in eliciting plasma extravasation. The neurokinin2 receptor agonist [Nle10]-neurokinin A4-10 (NK2 agonist) was not effective at 70 microM but produced a small and significant effect at 330 microM, whereas the neurokinin3 receptor agonist [MePhe7]-neurokinin B (NK3 agonist) was without effect at 40 microM or 400 microM. 4 Injections of SP or NKA into the synovial cavity of the rat knee were equally effective in producing marked plasma extravasation in remote sites such as the forelimb and hindlimb paws. 5 Co-administration experiments showed that the effects of SP were synergistic with NKA or the NK1 receptor agonist, but not with CGRP or the NK2 receptor agonist. 6 The rank order of potency was NK1 agonist greater than or equal to SP greater than NKB greater than NK2 agonist suggesting that NK1 receptors mediate plasma extravasation in the rat knee joint.     

Molecular characterisation of cloned bradykinin B1 receptors from rat and human.

This report describes the characterisation of cloned rat and human bradykinin B1 receptors in African green monkey kidney fibroblast (Cos-7) cells. A ligand binding assay with [3H]des-Arg10-kallidin was used to compare their pharmacology with respect to known bradykinin B1 and B2 receptor ligands. In addition, the pharmacology of T-kinin and its' derivative des-Arg11-T-kinin was investigated. The cloned rat receptor had a similar pharmacology to that of the recently described mouse receptor and differs from that described for the human receptor. The rat receptor had a higher affinity for des-Arg11-T-kinin than the human receptor. These differences in pharmacological properties may relate to the presence of T-kinin, bradykinin and their des-Arg derivatives as the major physiological peptides in rat and the predominance of kallidin and its derivatives in human. We confirm that the rat bradykinin B1 receptor gene is organised in a two exon structure and differs from the human gene which has a three exon structure and we further examine the inducible expression of this gene in a wide range of tissues using Northern blotting.     

NK2 receptors mediate plasma extravasation in guinea-pig lower airways.

1. Neurokinin (NK) receptor-mediated extravasation has been examined in guinea-pig airways by use of a recently described marker for microvascular protein leakage, 125I-labelled human fibrinogen. 2. Neurokinin A (NKA) caused a dose-dependent increase in plasma [125I]-fibrinogen extravasation in trachea, main bronchi, secondary bronchi and intraparenchymal airways. In contrast, the NK2 selective agonist [beta-Ala8]NKA(4-10) only caused extravasation in the secondary and intraparenchymal airways. 3. The NK2 selective antagonist, SR 48968, caused a dose-dependent inhibition of NKA and [beta-Ala8]NKA(4-10)-induced extravasation of fibrinogen in guinea-pig secondary bronchi and intraparenchymal airways. SR 48968 was without effect on the NKA-induced extravasation in trachea and main bronchi. 4. NKA- or [beta-Ala8]NKA(4-10)-induced plasma extravasation was not modified by pretreatment with histamine H1- or H2-receptor antagonists. 5. It is concluded that NK2 receptors mediate plasma [125I]-fibrinogen extravasation in guinea-pig secondary bronchi and intraparenchymal airways. This effect is direct and does not depend upon histamine released from mast cells.     

Involvement of tachykinins in plasma extravasation induced by bradykinin and low pH medium in the guinea-pig conjunctiva.

1. The effect of bradykinin, capsaicin, substance P and low pH medium on plasma extravasation in the guinea-pig conjunctiva has been studied. Evans blue dye was measured in the conjunctiva after local instillation of the agents into the conjunctival sac. 2. Bradykinin (2-50 nmol), capsaicin (20-50 nmol) and substance P (0.5-5 nmol) caused a dose-dependent increase in plasma extravasation with the following order of potency: substance P > bradykinin = capsaicin. The effect of capsaicin (50 nmol) and substance P (5 nmol) was abolished by the tachykinin NK1 receptor antagonist, CP-99,994 (8 mumol kg-1, i.v.) (P < 0.01), whereas CP-100,263 (8 mumol kg-1, i.v.) the inactive enantiomer of CP-99,994 was without effect. CP-99,994 inhibited by 70% (P < 0.01) the effect of bradykinin. 3. The kinin B2 receptor antagonist, Hoe 140 (icatibant, 10 nmol kg-1, i.v.) abolished the response to bradykinin (50 nmol) (P < 0.01), but did not affect the responses to capsaicin (50 nmol) or substance P (5 nmol). Plasma extravasation induced by low pH medium (pH 1) was abolished by CP-99,994 (P < 0.01) and by Hoe 140 (P < 0.01). 4. The present findings suggest that: endogenous or exogenous tachykinins increase plasma extravasation in the guinea-pig conjunctiva by activation of NK1 receptors; bradykinin-induced plasma extravasation is mediated by tachykinin release from sensory nerve endings; low pH media cause plasma extravasation via release of kinins that by activation of B2 receptors release tachykinins from sensory nerve endings.     

Detection of bradykinin B1 receptors in rat aortic smooth muscle cells

The tritiated bradykinin B1 receptor agonist [3H]des-Arg(10)-kallidin bound to a single class of high-affinity binding sites (K(d) = 0.5 +/- 0.16 nM; B(max) = 15,000 +/- 8,000 sites/cell) on cultured rat aortic smooth muscle cells. [3H]Des-Arg(10)-kallidin association and dissociation kinetics were monoexponential, making it possible to determine the association and dissociation rate constants (k(+1) = 1.5 10(5) M(-1) sec(-1); k(-1) = 4.2 10(-5) sec(-1)). [3H]Des-Arg(10)-kallidin binding was inhibited by specific ligands of bradykinin B1 and B2 receptors with a rank order of potency consistent with that known for bradykinin B1 receptors in other species (des-Arg(9)-[Leu(8)]bradykinin = des-Arg(10)-kallidin = des-Arg(9)-bradykinin = des-Arg(10)-[Leu(9)]kallidin > des-Arg(10)-HOE-140 > bradykinin > HOE-140). Bradykinin B1 receptor mRNA was also detected in these cells. Des-Arg(10)-kallidin increased cytosolic free Ca2+ levels, phosphoinositide turnover, and arachidonic acid release at nanomolar concentrations (respective EC(50) values: 16 +/- 2, 4 +/- 2.7, 6 +/- 2 nM). These functional effects of des-Arg(10)-kallidin could be blocked by the bradykinin B1 receptor antagonist des-Arg(9)-[Leu(8)]bradykinin, but were not sensitive to bradykinin B2 receptor antagonists. These results therefore show that rat aortic smooth muscle cells in culture express functional bradykinin B1 receptors.     

Direct evidence that capsaicin-induced plasma protein extravasation is mediated through tachykinin NK1 receptors.

The involvement of tachykinin NK1 receptors in the plasma protein extravasation (measured by the Evans blue leakage technique) produced by intravenous administration of capsaicin was investigated in the urinary bladder and trachea of anesthetized rats. Capsaicin-induced plasma extravasation was markedly inhibited by (+/-)-CP-96,345, a novel and potent non-peptide antagonist of tachykinin NK1 receptors. The same dose of (+/-)-CP-96,345 markedly inhibited the plasma protein extravasation induced by the selective NK1 receptor agonist, [Sar9]substance P sulfone, but had no effect on the response to histamine.     

The longitudinal muscle of rat ileum as a sensitive monoreceptor assay for bradykinin B1 receptors.

1. Various bradykinin derivatives, acting preferentially at B1 or B2 receptors, were tested in the isolated longitudinal smooth muscle of rat ileum. Experiments were carried out in the presence of chlorpheniramine and atropine (both 1 microM), guanethidine and indomethacin (both 3 microM) and of the peptidase inhibitors (captopril, bestatin and thiorphan, all 1 microM). 2. The rank order of potency was (pD2 values +/- s.e.mean, n = 5 in parentheses, at 5 h from set-up): [des-Arg9]-BK (8.27 +/- 0.11) > or = [des-Arg10]-kallidin (7.67 +/- 0.24) > bradykinin (6.69 +/- 0.25). The B2 receptor selective agonist, [Hyp3,Tyr(Me)8]-BK, was approximately 10 fold less active than bradykinin. Contractile responses to all agonists increased with time. The maximal response to the B1 receptor agonist, [desArg9]-BK at 5 h (94 +/- 2%) was significantly (P < 0.05) greater than that measured at 2 h (74 +/- 2%). 3. The B2 receptor antagonist, D-Arg[Hyp3, Thi5, D-Tic7, Oic8]-BK (Hoe 140, 0.1 microM) did not affect responses to the B1 receptor agonist [des-Arg9]-BK (0.1 nM--1 microM) nor those to the B2 receptor agonist, [Hyp3,Tyr(Me)8]-BK (1 nM--10 microM). In control experiments performed in the longitudinal smooth muscle of guinea-pig ileum and rat isolated urinary bladder as bioassays for B2 receptors, the B2 receptor antagonist Hoe 140 (0.1 microM) antagonized bradykinin-induced contractions. 4. In the rat isolated ileum the B1 receptor antagonist, D-Arg[Hyp3, Thi5, D-Tic7, Oic8, des-Arg9]-BK ([des-Arg10]-Hoe 140, 0.3 - 10 microM) competitively antagonized contractile responses to [des-Arg9]-BK with an estimated pKB of 6.74 +/- 0.08 (Schild plot slope with confidence limits 1.22, (0.70 - 1.73) n = 13). In control experiments in the guinea-pig isolated ileum and rat isolated urinary bladder, [des-Arg10]-Hoe 140 (1 - 10 microM) did not inhibit B2 receptor-mediated contractile responses. 5. The putative B1 receptor antagonist, [Leu8,des-Arg9]-BK, behaved as a partial agonist when responses were determined 2 h from set-up (pD2 6.43 +/- 0.21, n = 5; Emax 30% of that evoked by [des-Arg9]-BK); at 5 h from set-up it behaved as a full agonist (pD2 7.48 +/- 0.12, n = 5; Emax 90% of that evoked by [des-Arg9]-BK). At this time the response to [Leu8,des-Arg9]-BK was antagonized in a concentration-dependent manner by [des-Arg10]-Hoe 140, which at 1 microM and 10 microM, produced dose-ratios of 6.33 +/- 3.66 (n = 4) and 103 +/- 40 (n = 4). 6. In view of the rank order of potency of agonists, the antagonist activity by [des-Arg10]-Hoe 140 and the lack of antagonist activity of Hoe 140, we conclude that the longitudinal smooth muscle of rat ileum, after histamine, acetylcholine, noradrenaline, and prostanoid production blockade, is a sensitive monoreceptor assay for studying the pharmacology of bradykinin B1 receptors. Further the preparation can also be used as a sensitive bioassay to identify partial agonist activity of B1 receptor antagonists such as [Leu8,desArg9]-BK.     

Involvement of bradykinin B1 and B2 receptors in relaxation of mouse isolated trachea

1. The aim of the present study was to investigate the effects of bradykinin and [des-Arg⁹]-bradykinin and their relaxant mechanisms in the mouse isolated trachea.
2. In the resting tracheal preparations with intact epithelium, bradykinin and [des-Arg⁹]-bradykinin (each drug, 0.01–10 μM) induced neither contraction nor relaxation. In contrast, bradykinin (0.01–10 μM) induced concentration-dependent relaxation when the tracheal preparations were precontracted with methacholine (1 μM). The relaxation induced by bradykinin was inhibited by the B₂ receptor antagonist, D-Arg⁰-[Hyp³,Thi⁵,D-Tic⁷,Oic⁸]-bradykinin (Hoe 140, 0.01–1 μM) in a concentration-dependent manner whereas the B₁ receptor antagonist, [des-Arg⁹,Leu⁸]-bradykinin (0.01–1 μM), had no inhibitory effect on bradykinin-induced relaxation. [des-Arg⁹]-bradykinin (0.01–10 μM) also caused concentration-dependent relaxation after precontraction with methacholine. The relaxation induced by [des-Arg⁹]-bradykinin was concentration-dependently inhibited by the B₁ receptor antagonist, [des-Arg⁹,Leu⁸]-bradykinin (0.01–1 μM), whereas the B₂ receptor antagonist, Hoe 140 (0.01–1 μM) was without effect.
3. In the presence of the cyclo-oxygenase inhibitor, indomethacin (0.01–1 μM), the relaxations induced by bradykinin and [des-Arg⁹]-bradykinin were inhibited concentration-dependently.
4. Two nitric oxide (NO) biosynthesis inhibitors N^G-nitro-L-arginine methyl ester (L-NAME, 100 μM) and N^G-nitro-L-arginine (L-NOARG, 100 μM) had no inhibitory effects on the relaxations induced by bradykinin and [des-Arg⁹]-bradykinin. Neither did the selective inhibitor of the soluble guanylate cyclase, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10 μM) inhibit the relaxations induced by bradykinin and [des-Arg⁹]-bradykinin.
5. Prostaglandin E₂ (PGE₂, 0.01–33 μM) caused concentration-dependent relaxation of the tracheal preparations precontracted with methacholine. Indomethacin (1 μM) and ODQ (10 μM) exerted no inhibitory effects on the relaxation induced by PGE₂.
6. The NO-donor, sodium nitroprusside (SNP; 0.01–100 μM) also caused concentration-dependent relaxation of the tracheal preparations precontracted with methacholine. ODQ (0.1–1 μM) concentration-dependently inhibited the relaxation induced by SNP.
7. These data demonstrate that bradykinin and [des-Arg⁹]-bradykinin relax the mouse trachea precontracted with methacholine by the activation of bradykinin B₂-receptors and B₁-receptors, respectively. The stimulation of bradykinin receptors induces activation of the cyclo-oxygenase pathway, leading to the production of relaxing prostaglandins. The NO pathway is not involved in the bradykinin-induced relaxation. The relaxation caused by NO-donors in the mouse trachea is likely to be mediated via activation of soluble guanylate cyclase.

     

Involvement of tachykinin receptors in Clostridium perfringens beta-toxin-induced plasma extravasation

1 Clostridium perfringens beta-toxin causes dermonecrosis and oedema in the dorsal skin of animals. In the present study, we investigated the mechanisms of oedema induced by the toxin. 2 The toxin induced plasma extravasation in the dorsal skin of Balb/c mice. 3 The extravasation was significantly inhibited by diphenhydramine, a histamine 1 receptor antagonist. However, the toxin did not cause the release of histamine from mouse mastocytoma cells. 4 Tachykinin NK(1) receptor antagonists, [D-Pro(2), D-Trp(7,9)]-SP, [D-Pro(4), D-Trp(7,9)]-SP and spantide, inhibited the toxin-induced leakage in a dose-dependent manner. Furthermore, the non-peptide tachykinin NK(1) receptor antagonist, SR140333, markedly inhibited the toxin-induced leakage. 5 The leakage induced by the toxin was markedly reduced in capsaicin-pretreated mouse skin but the leakage was not affected by systemic pretreatment with a calcitonin gene-related peptide receptor antagonist (CGRP(8-37)). 6 The toxin-induced leakage was significantly inhibited by the N-type Ca(2+) channel blocker, omega-conotoxin MVIIA, and the bradykinin B(2) receptor antagonist, HOE140 (D-Arg-[Hyp(3), Thi(5), D-Tic(7), Oic(8)]-bradykinin), but was not affected by the selective L-type Ca(2+) channel blocker, verapamil, the P-type Ca(2+) channel blocker, omega-agatoxin IVA, tetrodotoxin (TTX), the TTX-resistant Na(+) channel blocker, carbamazepine, or the sensory nerve conduction blocker, lignocaine. 7 These results suggest that plasma extravasation induced by beta-toxin in mouse skin is mediated via a mechanism involving tachykinin NK(1) receptors.     

Characterisation of bradykinin B1 and B2 receptors using rat isolated vas deferens

The actions of bradykinin and its metabolite des-Arg(9) bradykinin are mediated through activation of bradykinin B(2) and B(1) receptors, respectively. The aim of the present study was to characterize native bradykinin receptors focusing on induction and desensitization using rat isolated vas deferens. Tissues were mounted in organ baths for isometric recordings and neurogenically mediated contractions were evoked by electrical stimulation. Des-Arg(9) bradykinin enhanced the magnitude of the electrically evoked contractions and this effect (which was sensitive to blockade by the peptide bradykinin B(1) receptor selective antagonist B9858, Lys-Lys-(Hyp(3),Cpg(5),D-Tic(7),Cpg(8))des-Arg(9) bradykinin) was only observed following a pre-incubation period and was greatest following 5 h of pre-incubation. Bradykinin also potentiated neurogenically evoked contractions and this effect was sensitive to blockade by Hoe 140 (D-Arg(Hyp(3),Thi(5),D-Tic(7),Oic(8))bradykinin, a peptide bradykinin B(2) receptor antagonist) and was present without pre-incubation but was increased by pre-incubation and reached maximum at the 5-h incubation time point. Responses to bradykinin were larger than those to des-Arg(9) bradykinin. Bradykinin responses did not show desensitization on repeated agonist stimulation. These data confirm in rat isolated vas deferens bradykinin B(2), but not B(1), receptors are constitutively expressed, that both receptor populations are inducible and B(2) receptors do not exhibit desensitization.     

Role of bradykinin in inflammatory arthritis: identification and functional analysis of bradykinin receptors on human synovial fibroblasts.

Receptor type and function of bradykinin (BK) receptors on human synovial fibroblasts (HSF) was determined. Scatchard analysis of [3H]BK saturation binding to intact synovial cells revealed a single binding site, with a Kd of 3.8 +/- 0.6 nM. HSF express approximately 50,000 BK sites/cell. Specificity of [3H]BK binding was confirmed by the ability of several BK peptide agonists and antagonists to inhibit binding in a dose dependent manner. The rank order of potency for agonist inhibition of [3H]BK and the inability of selective antagonists of the B1-type to displace binding suggest that the BK receptor on HSF is a B2 subtype receptor. The addition of BK to HSF caused a time and concentration dependent increase in PGE2 production. This BK induced PGE2 production was blocked by specific B2 type BK antagonists and not by B1 antagonists. The results of this study identify B2 type BK receptors on synovial fibroblasts and suggest that BK may be a primary mediator in inflammatory arthritis.     

Effects of the orally active non-peptide bradykinin B2 receptor antagonist, FR173657, on plasma extravasation in guinea pig airways

We investigated the effect of the orally active non-peptide bradykinin B2 receptor antagonist, FR173657 (E)-3-(6-acetamido-3-pyridyl)-N-[N-[2.4-di-chloro-3-[(2-methyl-8-quinoli nyl)oxymethyl]phenyl]-N-methy-laminocarbonylmethyl] acrylamide), on plasma extravasation mediated by activation of sensory nerves in guinea pig airways. Plasma extravasation was assessed by the photometric measurement of the extravasated Evans blue after formamide extraction. We found that the increase in Evans blue dye extravasation evoked by an aerosol of bradykinin (0.1 mM, 2 min) in the presence of phosphoramidon (2.5 mg/kg, i.v.) was abolished completely by FR173657 (20 mg/kg, p.o.) in the trachea and main bronchi. In sensitized guinea pigs pretreated with phosphoramidon, FR173657 (20 mg/kg, p.o.) inhibited plasma extravasation evoked by ovalbumin aerosol (5%, 2 min) by 77+/-14.2% in the trachea and 65+/-11.2% in the main bronchi. FR173657 (20 mg/kg, p.o.) did not affect the plasma extravasation caused by aerosolised capsaicin. These findings suggest that FR173657 is an orally active, promising anti-inflammatory agent for kinin-dependent inflammation following antigen challenge.     

Effects of a selective bradykinin B1 receptor antagonist on increased plasma extravasation in streptozotocin-induced diabetic rats: distinct vasculopathic profile of major key organs

Diffuse vasculopathy is a common feature of the morbidity and increased mortality associated with insulino-dependent type 1 diabetes. Increased vascular permeability leading to plasma extravasation occurs in surrounding tissues following endothelial dysfunction. Such micro- and macro-vascular complications develop over time and lead to oedema, hypertension, cardiomyopathy, renal failure (nephropathy) and other complications (neuropathy, retinopathy). In the present investigation, we studied the effect of a selective bradykinin B(1) receptor antagonist, R-954, on the enhanced vascular permeability in streptozotocin (STZ)-induced diabetic Wistar rats compared with age-matched controls. Plasma extravasation was determined using Evans blue dye in selected target tissues (left and right heart atria, ventricles, lung, abdominal and thoracic aortas, liver, spleen, renal cortex and medulla), at 1 and 4 weeks following STZ administration. The vascular permeability was significantly increased in the aortas, cortex, medulla, and spleen in 1-week STZ rats and remained elevated at 4 weeks of diabetes. Both atria showed an increased vascular permeability only after 4-week STZ-administration. R-954 (2 mg/kg, bolus, s.c.), given 2 h prior to Evans blue dye, to 1- and 4-week diabetic rats significantly inhibited (by 48-100%) plasma leakage in most tested tissues affected by diabetes with no effect in healthy rats. These results showed that the inducible bradykinin B(1) receptor subtype participates in the modulation of the vascular permeability in diabetic rats and suggest that selective bradykinin B(1) receptor antagonism could have a beneficial role in reducing diabetic vascular complications.     

Role of bradykinin B(1) receptors in diabetes-induced hyperalgesia in streptozotocin-treated mice

Insulin-dependent diabetes mellitus (type-1 diabetes) is an inflammatory autoimmune disease associated with vascular permeability changes leading to many complications including nephropathy, retinopathy, hypertension, hyperalgesia and neuropathy. The bradykinin B(1) receptor was recently found to be upregulated during the development of the diabetes and to be involved in its complications. Kinins are known to be important mediators of a variety of biological effects including cardiovascular homeostasis, inflammation and nociception. In the present study, we studied the effect of the selective B(1) receptor agonist, des-Arg(9)-bradykinin, and its specific antagonists, Ac-Lys-[D-beta Nal(7), Ile(8)]des-Arg(9)-bradykinin (R-715) and Ac-Orn-[Oic(2), alphaMe Phe(5), D-beta Nal(7), Ile(8)]des-Arg(9)-bradykinin (R-954), on diabetic hyperalgesia. Diabetes was induced in male CD-1 mice by injecting a single high dose of streptozotocin (200 mg kg(-1), i.p.) and the nociception was assessed using the hot plate and the tail flick tests, 1 week following the injection of streptozotocin. Our results showed that induction of diabetes by streptozotocin provoked a marked hyperalgesia in diabetic mice expressed as about 11% decrease in hot plate reaction time and 26% decrease in tail flick reaction time. Following acute administration of R-715 (200-800 microg kg(-1), i.p.) and R-954 (50-600 microg kg(-1), i.p.), this hyperalgesic activity was blocked and the hot plate and tail flick latencies of diabetic mice returned to normal values observed in control healthy mice. In addition, the acute administration of des-Arg(9)-bradykinin (200-600 microg kg(-1), i.p.) significantly potentiated diabetes-induced hyperalgesia, an effect that was totally reversed by R-715 (1.6-2.4 mg kg(-1), i.p.) and R-954 (0.8-1.6 mg kg(-1), i.p.). These results provide a major evidence for the implication of the bradykinin B(1) receptors in the development of hyperalgesia associated with diabetes and suggest a novel approach to the treatment of this diabetic complication using the bradykinin B(1) receptor antagonists.