kallidin and icatibant

Animal models suggest a vasomotor role for the B1 kinin receptor in cardiovascular disease states. In patients with heart failure treated with angiotensin-converting enzyme inhibition (ACEi), or combined B1/B2 receptor antagonism, but not B2 receptor antagonism alone, causes vasoconstriction. However, B1 agonism has no effect on vasomotor or fibrinolytic function. Findings from transgenic animals lacking the B2 receptor suggest that these conflicting data may be explained by cross-talk between B1 and B2 receptors. We hypothesized that B1 stimulation causes vasodilatation and tissue plasminogen activator release in the human forearm when B2 receptor signaling is inhibited. Forearm blood flow was measured in 16 patients with heart failure receiving ACEi. In double-blinded crossover studies, intrabrachial Lys-[Leu8]-des-Arg9-bradykinin (B1 antagonist), lys-des-Arg9-bradykinin (B1 agonist), bradykinin (B2 agonist), and sodium nitroprusside (endothelium-independent vasodilator) were infused alone or with HOE-140 (B2 antagonist). HOE-140 did not affect basal vascular tone or t-PA release, but it abolished bradykinin-induced vasodilatation and t-PA release (P < 0.0001). Blood flow and t-PA release were unaffected by B1 agonism or antagonism in the presence and absence HOE-140. Our findings do not support a role for crosstalk between the B1 and B2 kinin receptors in the human peripheral circulation.

Topics: Adult; Aged; Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Bradykinin; Bradykinin B1 Receptor Antagonists; Bradykinin B2 Receptor Antagonists; Cross-Over Studies; Double-Blind Method; Female; Heart Failure; Humans; Infusions, Intra-Arterial; Kallidin; Middle Aged; Nitroprusside; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Regional Blood Flow; Tissue Plasminogen Activator; Vasodilation

Topics: Animals; Bradykinin; Bradykinin Receptor Antagonists; Hyperalgesia; Kallidin; Kallikreins; Kinins; Male; Pain Measurement; Rats; Rats, Wistar

The discovery of novel analgesic compounds that target some receptors can be challenging due to species differences in ligand pharmacology. If a putative analgesic compound has markedly lower affinity for rodent versus other mammalian orthologs of a receptor, the evaluation of antinociceptive efficacy in non-rodent species becomes necessary. Here, we describe a new, efficient method for measuring inflammation-associated nociception in conscious rabbits. An electronic von Frey device is used, consisting of a rigid plastic tip connected to a force transducer in a hand-held probe. The plastic tip is applied to the plantar surface of a hind paw with increasing force until a withdrawal response is observed. The maximum force (g) tolerated by the rabbit (i.e., withdrawal threshold) is recorded. In young, conscious rabbits (500-700 g), baseline hind paw withdrawal thresholds typically fell within the 60-80 g range. Three hours after injection of the inflammatory agent carrageenan (3%, 200 microL, intra-plantar), withdrawal thresholds dropped by approximately 30-40 g, indicating the presence of punctate mechanical hyperalgesia. The development of hyperalgesia was dose dependently prevented by the NSAID indomethacin (ED50=2.56 mg/kg, p.o.) or the bradykinin B2 receptor peptide antagonist HOE 140 (intra-paw administration). An established hyperalgesia was dose dependently reversed by morphine sulfate (ED50=0.096 mg/kg, s.c.) or the bradykinin B1 receptor peptide antagonist [des-Arg10, Leu9]-kallidin (ED50=0.45 mg/kg, s.c.). Rabbits treated with the novel B(1) receptor small molecule antagonist compound A also showed dose-dependent reversal of hyperalgesia (ED50=20.19 mg/kg, s.c.) and analysis of plasma samples taken from these rabbits showed that, unlike other rabbit pain models, the current method permits the evaluation of pharmacokinetic-pharmacodynamic (PK-PD) relationships (compound A plasma EC50=402.6 nM). We conclude that the Electrovonfrey method can be used in rabbits with inflammatory pain to generate reliable dose- and plasma concentration-effect curves for different classes of analgesics.

Topics: Analysis of Variance; Animals; Anti-Inflammatory Agents, Non-Steroidal; Bradykinin; Carrageenan; Dose-Response Relationship, Drug; Drug Interactions; Ethers; Hydrocarbons, Fluorinated; Hyperalgesia; Indomethacin; Inflammation; Kallidin; Metacarpus; Pain; Pain Measurement; Pain Threshold; Rabbits; Reaction Time; Spectrum Analysis; Time Factors

Kinins have an important role in inflammatory cystitis and in animal pathophysiological models, by acting on epithelium, fibroblasts, sensory innervation and smooth muscle. The aim of this study was to characterize the receptors responsible for direct motor responses induced by kinins on human detrusor.. Human detrusor cells from biopsies were isolated and maintained in culture. B(1) and B(2) kinin receptors were characterized by means of radioligand and functional experiments (PI accumulation and PGE(2) release).. [(3)H]-[desArg(9)]-Lys-BK and [(3)H]-BK saturation studies indicated receptor density (B(max)) and K (d) values of 19 or 113 fmol mg(-1), and 0.16 or 0.11 nM for the B(1) or B(2) receptors, respectively. Inhibition binding studies indicated the selectivity of the B(1) receptor antagonist [desArg(9)Leu(8)]-Lys-BK and of the B(2) receptor antagonists Icatibant and MEN16132. [DesArg(9)]-Lys-BK and BK induced PI accumulation with an EC(50) of 1.6 and 1.4 nM and different maximal responses (E(max) of [desArg(9)]-Lys-BK was 10% of BK). BK also induced prostaglandin E(2) release (EC(50) 2.3 nM), whereas no response was detected with the B(1) receptor agonist. The incubation of detrusor smooth muscle cells with interleukin 1beta (IL-1beta) or tumour necrosis factor-alpha (TNF-alpha) (10 ng ml(-1)) induced a time-dependent increase in radioligand-specific binding, which was greater for the B(1) than for the B(2) receptor.. Human detrusor smooth muscle cells in culture retain kinin receptors, and represent a suitable model to investigate the mechanisms and changes that occur under chronic inflammatory conditions.

Topics: Bradykinin; Bradykinin B1 Receptor Antagonists; Cells, Cultured; Dinoprostone; Humans; Inositol Phosphates; Interleukin-1beta; Kallidin; Male; Middle Aged; Muscle, Smooth; Ornithine; Radioligand Assay; Receptor, Bradykinin B1; Sulfonamides; Transforming Growth Factor alpha; Urinary Bladder

This study analyzed bradykinin (BK)-evoked contractile responses in the mouse colon under normal and inflammatory conditions. BK and the preferential B(2) receptor agonists Hyp(3)-BK, Lys-BK, Met-Lys-BK and Tyr(8)-BK produced a marked and concentration-related contraction of the normal mouse colon, whereas the selective B(1) receptor agonist des-Arg(9)-BK had no effect. BK-induced contraction was concentration-dependently antagonized (in a non-competitive manner) by both B(2) receptor antagonists Hoe 140 and FR173657, but not the B(1) receptor antagonist des-Arg(9)-[Leu(8)]-BK. Analysis of the possible mechanisms implicated in the contractile responses of BK in the mouse colon revealed the involvement of the neural release of acetylcholine, the activation of L- and N-type voltage-gated calcium channels, and the release of neuropeptides, prostanoids and leukotrienes. The contraction induced by BK was markedly increased in preparations obtained from TNBS-treated mice. The up-regulation of B(2) receptors following the induction of colitis was confirmed with binding studies using [(3)H]-BK, which revealed a marked increase in B(2) receptor densities, without alterations of affinity. We provide convincing evidence on the relevance of B(2) receptors in the mouse colon under normal conditions, as well as under an inflammatory profile of colitis. Selective B(2) receptor antagonists might well represent rational therapeutic options for treating inflammatory bowel diseases.

Topics: Acetylcholine; Animals; Bradykinin; Bradykinin B2 Receptor Antagonists; Calcium Channels, L-Type; Calcium Channels, N-Type; Colitis; Colon; Dose-Response Relationship, Drug; Kallidin; Leukotrienes; Male; Mice; Muscle Contraction; Neuropeptides; Prostaglandins; Quinolines; Receptor, Bradykinin B2; Trinitrobenzenesulfonic Acid

Bradykinin is well known to have a biphasic action to contract and relax gastrointestinal tissue. However, no studies have investigated the potential action of bradykinin to affect the peristaltic reflex. In the present study, serosally applied bradykinin (1-1000 nM) and the bradykinin B2 receptor agonist, kallidin (1-1000 nM), had inhibitory actions and increased the pressure threshold for peristalsis (maximum changes seen at 1000 nM were approximately 60 Pa), as did morphine (IC50=22.3+/-4.8 nM; maximum increase in the pressure threshold was approximately 130 Pa). Conversely, the B1 kinin receptor agonist, [des-Arg9]-bradykinin (1-1000 nM), had no effect (P>0.05). Two potent B2 receptor antagonists, FR173657 (1 and 100 nM) and icatibant (10 nM), significantly antagonized the inhibitory action of serosally applied bradykinin on peristalsis (P<0.01), whilst the B1 receptor antagonist, Lys-[des-Arg9, Leu8]-bradykinin (100 nM) was inactive (P>0.05). In comparison, 5-hydroxytryptamine (1-1000 nM) facilitated peristalsis (EC50=37.7+/-23.0 nM; maximum reduction of the pressure threshold for peristalsis was approximately 76 Pa), as did FR173657 at 100 nM (reducing the pressure threshold for peristalsis by approximately 15 Pa; P<0.05) but icatibant at 10 nM was inactive (P>0.05). The results indicate that bradykinin B2 receptors mediate an inhibition of peristalsis in the guinea pig isolated ileum.

Topics: Animals; Bradykinin; Bradykinin B2 Receptor Antagonists; Guinea Pigs; Ileum; In Vitro Techniques; Kallidin; Male; Morphine; Muscle, Smooth; Peristalsis; Pressure; Quinolines; Receptor, Bradykinin B2; Reflex; Serotonin

The role of kinins, well known as peripheral inflammatory mediators, in the modulation of brain inflammation is unclear. The present data show that bradykinin, a bradykinin B(2) receptor agonist, enhanced both basal and lipopolysaccharide-induced prostaglandin E(2) synthesis in rat neonatal glial cells in culture. By contrast, Lys-des-Arg(9)-bradykinin, which is a kinin breakdown product and a selective bradykinin B(1) receptor agonist, attenuated both basal and lipopolysaccharide-induced production of prostaglandin E(2) in glia. These results suggest a feedback regulatory mechanism of kinins on glial cells, in which prostaglandin synthesis is initially enhanced by bradykinin (B(2)) and eventually blocked by the effect of the kinin breakdown product, acting on bradykinin B(1) receptors.

Topics: Animals; Animals, Newborn; Bradykinin; Cells, Cultured; Dinoprostone; Dose-Response Relationship, Drug; Encephalitis; Kallidin; Kinins; Lipopolysaccharides; Neuroglia; Rats; Rats, Wistar; Receptor, Bradykinin B1; Receptor, Bradykinin B2

The N-terminal sequence of icatibant, a widely used peptide antagonist of the bradykinin B(2) receptors, is analogous to that of other known aminopeptidase N inhibitors. Icatibant competitively inhibited the hydrolysis of L-Ala-p-nitroanilide by recombinant aminopeptidase N (K(i) 9.1 microM). In the rabbit aorta, icatibant (10-30 microM) potentiated angiotensin III, but not angiotensin II (contraction mediated by angiotensin AT(1) receptors), and Lys-des-Arg(9)-bradykinin, but not des-Arg(9)-bradykinin (effects mediated by the bradykinin B(1) receptors), consistent with the known susceptibility of these agonists to aminopeptidase N. At concentrations possibly reached in vivo (e.g., in kidneys), icatibant alters physiological systems different from bradykinin B(2) receptors.

Topics: Angiotensin II; Angiotensin III; Aniline Compounds; Animals; Aorta; Bradykinin; Bradykinin B2 Receptor Antagonists; CD13 Antigens; Dose-Response Relationship, Drug; In Vitro Techniques; Kallidin; Kinetics; Protease Inhibitors; Quinolines; Rabbits; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, Angiotensin; Recombinant Proteins; Signal Transduction; Vasoconstriction; Vasoconstrictor Agents

The proinflammatory mediator bradykinin (BK) is suggested to play an important role in the pathogenesis of various inflammatory diseases including periodontitis. In this study, BK per se stimulated interleukin-8 (IL-8) production in human gingival fibroblasts in vitro. Furthermore, BK upregulated the stimulatory effect of the cytokines IL-1beta and TNFalpha on the production of IL-8. The stimulatory effect of BK on the IL-1beta- or TNFalpha-stimulated IL-8 production was reduced in the presence of BK B2 receptor antagonist HOE 140, whereas the B1 receptor antagonist Lys-(des-arg9, Leu8)-BK had no effect. Similar to BK, the calcium ionophore A23187 also upregulated the stimulatory effect of IL-1beta and TNFalpha on IL-8 production. The protein kinase C (PKC) inhibitor bisindolylmaleimide, BIS, significantly reduced the stimulatory effect of BK on IL-1beta and TNFalpha increased IL-8 production but did not affect the production of IL-8 stimulated by cytokines alone. The specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB 203580 reduced IL-8 production stimulated by the combination of BK and IL-1beta as well as the IL-1beta-stimulated IL-8 production. In conclusion, this study shows that BK upregulates IL-1beta- and TNFalpha-stimulated IL-8 production via BK B2 receptor and that PKC signal pathway seems to be involved in the upregulation of the cytokine-induced IL-8 production in gingival fibroblasts. This stimulatory effect of BK on IL-8 production may contribute to the maintenance of the gingival inflammation and enhanced risk for destruction of gingival connective tissue.

Topics: Adolescent; Bradykinin; Bradykinin B2 Receptor Antagonists; Calcimycin; Cells, Cultured; Child; Fibroblasts; Gingiva; Humans; Imidazoles; Indoles; Interleukin-1; Interleukin-8; Ionophores; Kallidin; Maleimides; MAP Kinase Kinase 2; Protein Kinase C; Pyridines; Receptor, Bradykinin B2; Tumor Necrosis Factor-alpha; Up-Regulation

This study was designed to investigate the mechanisms by which bradykinin induces contraction of the pig iris sphincter muscle in vitro. Addition of bradykinin, Lys-bradykinin and Met-Lys-bradykinin to the pig iris sphincter resulted in a graded contraction with a mean EC(50s) of 21, 11 and 5 nM, respectively. The bradykinin B(1) receptor agonist des-Arg(9)-bradykinin only caused a slight contraction, measured 6 h after the tissue was set up. The B(2) receptor antagonists FR 173657 ((E)-3-(6-acetamido-3-pyridyl)-N [N-2-4-dichloro-3-[(2-methyl-8-quinolinyl) oxymethyl] phenyl]-N-methylamino-carbonyl-ethyl] acrylamide) and Hoe 140 (D-Arg(0)-[Hyp(3), Thi(5), D-Tic(7), Oic(8)]-bradykinin produced a graded shift to the right associated with marked inhibition of the bradykinin-induced contraction. Atropine, guanethidine or tetrodotoxin significantly reduced the bradykinin-induced contraction. Dazoxiben, an inhibitor of thromboxane A(2), and MK-571 (3-(3-(2-(7-chloro-2-quinolinyl) ethenyl) phenyl ((3-dimethyl amino-3oxo-propyl) thio) methyl) propanoic acid, a leukotriene D(4) receptor-selective antagonist, also caused inhibition of the bradykinin-mediated contraction. Cyclooxygenase-1 and -2 inhibitors, indomethacin, ibuprofen, valeryl salicylate and NS 398 (N-[2-(cyclohexyloxy)-4-nitrophenyl]methanosulfonamide) all significantly inhibited the bradykinin-mediated contraction without affecting the carbachol-induced contraction of the pig iris sphincter. Taken together, these results indicate that the bradykinin-mediated contraction of the pig iris sphincter muscle seems to be mediated primarily by the activation of the B(2) receptor release of acetylcholine, noradrenaline and both cyclooxygenase-1 and -2 metabolites besides the release of leukotriene D(4) and tromboxane A(2) from the arachidonic acid pathway.

Topics: Animals; Atropine; Bradykinin; Bradykinin Receptor Antagonists; Cyclooxygenase Inhibitors; Dose-Response Relationship, Drug; Enzyme Inhibitors; Guanethidine; Ibuprofen; Imidazoles; In Vitro Techniques; Indomethacin; Iris; Kallidin; Muscle Contraction; Muscle, Smooth; Nitrobenzenes; Propionates; Quinolines; Salicylates; Sulfonamides; Swine; Tetrodotoxin; Thromboxane-A Synthase

Kininase I-type carboxypeptidases convert native kinin agonists for B(2) receptors into B(1) receptor agonists by specifically removing the COOH-terminal Arg residue. The membrane localization of carboxypeptidase M (CPM) and carboxypeptidase D (CPD) make them ideally situated to regulate kinin activity. Nitric oxide (NO) release from human lung microvascular endothelial cells (HLMVEC) was measured directly in real time with a porphyrinic microsensor. Bradykinin (1-100 nM) elicited a transient (5 min) peak of generation of NO that was blocked by the B(2) antagonist HOE 140, whereas B(1) agonist des-Arg(10)-kallidin caused a small linear increase in NO over 20 min. Treatment of HLMVEC with 5 ng/ml interleukin-1beta and 200 U/ml interferon-gamma for 16 h upregulated B(1) receptors as shown by an approximately fourfold increase in prolonged (>20 min) output of NO in response to des-Arg(10)-kallidin, which was blocked by the B(1) antagonist des-Arg(10)-Leu(9)-kallidin. B(2) receptor agonists bradykinin or kallidin also generated prolonged NO production in treated HLMVEC, which was significantly reduced by either a B(1) antagonist or carboxypeptidase inhibitor, and completely abolished with a combination of B(1) and B(2) receptor antagonists. Furthermore, CPM and CPD activities were increased about twofold in membrane fractions of HLMVEC treated with interleukin-1beta and interferon-gamma compared with control cells. Immunostaining localized CPD primarily in a perinuclear/Golgi region, whereas CPM was on the cell membrane. These data show that cellular kininase I-type carboxypeptidases can enhance kinin signaling and NO production by converting B(2) agonists to B(1) agonists, especially in inflammatory conditions.

Topics: Bradykinin; Capillaries; Carboxypeptidases; Cell Line; Cell Membrane; Endothelium, Vascular; Humans; Immunohistochemistry; Interferon-gamma; Interleukin-1; Kallidin; Lysine Carboxypeptidase; Nitric Oxide; Pulmonary Circulation; Receptor, Bradykinin B1; Receptors, Bradykinin; Stimulation, Chemical; Subcellular Fractions; Up-Regulation

We evaluated roles of kinins in allergen-induced nasal blockage and sneezing, and development of nasal hyperresponsiveness to leukotriene D4 in a Japanese cedar pollen-induced allergic rhinitis model of guinea pigs. Sensitised guinea pigs were repeatedly challenged by pollen inhalation once every week. Neither a bradykinin B1 receptor antagonist, des-Arg9-[Leu8]bradykinin nor a bradykinin B2 receptor antagonist, icatibant suppressed allergen-induced sneezing and nasal blockage. However, development of nasal hyperresponsiveness to leukotriene D4 was significantly suppressed by them. The amount of bradykinin in nasal cavity lavage fluid was immediately increased after the challenge. In non-sensitised animals, hyperresponsiveness to leukotriene D4 was developed by a bradykinin B2 receptor agonist, bradykinin, but not by a bradykinin B1 receptor agonist, des-Arg10-kallidin, while in the sensitised-challenged animal, both agonists developed hyperresponsiveness. In conclusion, the nasal hyperresponsiveness appeared to be induced by kinins produced in response to the antigen challenge through activation of not only bradykinin B2 but also B1 receptors.

Topics: Airway Resistance; Allergens; Animals; Bradykinin; Bradykinin B1 Receptor Antagonists; Bradykinin B2 Receptor Antagonists; Disease Models, Animal; Guinea Pigs; Kallidin; Kinins; Leukotriene D4; Male; Nasal Lavage Fluid; Pollen; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Rhinitis, Allergic, Seasonal; Time Factors

The present study was performed to: (a) evaluate the effects of kinin B1 (Sar[D-Phe8]-des-Arg9-BK; 10 nmol/kg) and B2 (bradykinin (BK); 10 nmol/kg) receptor agonists on plasma extravasation in selected rat tissues; (b) determine the contribution of a lipopolysaccharide (LPS) (100 microg/kg) to the effects triggered by B1 and B2 agonists; and (c) characterize the selectivity of B1 ([Leu8]desArg9-BK; 10 nmol/kg) and B2 (HOE 140; 10 nmol/kg) antagonists as inhibitors of this kinin-induced phenomenon. B1 and B2 agonists were shown to increase plasma extravasation in the duodenum, ileum and also in the urinary bladder of the rat. LPS pretreatment enhanced the plasma extravasation mediated only by the B1 agonist in the duodenum, ileum, trachea, main and segmentar bronchi. These effects were prevented by the B1. but not the B2 antagonist. In normal rats, the B2 antagonist inhibited the effect of B2 agonist in all the tissues analyzed. However, in LPS-treated rats, the B2 antagonist was ineffective in the urinary bladder. These results indicate that kinins induce plasma extravasation in selected rat tissues through activation of B1 and B2 receptors, and that LPS selectively enhances the kinin effect on the B1 receptor in the duodenum, ileum, trachea and main and segmentar bronchi, and may increase B1 receptor expression in these tissues.

Topics: Animals; Bradykinin; Bradykinin Receptor Antagonists; Duodenum; Ileum; Kallidin; Lipopolysaccharides; Rats; Rats, Wistar; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, Bradykinin; Trachea; Urinary Bladder

To investigate the molecular basis for the specificity of ligand recognition in human kinin B(1) (B(1)R) and B(2) (B(2)R) receptors, we constructed a series of chimeric receptors by progressively replacing, from the N to the C terminus, the human B(2)R domains by their B(1) counterparts. The chimeric construct possessing the C-terminal tail and the transmembrane domain VII (TM VII) of the B(2)R (construct 6) displayed 7- and 20- fold decreased affinities for the B(1) agonist [(3)H]desArg(10)-kallidin (desArg(10)-KD) and the B(1) antagonist [(3)H]desArg(10)-[Leu(9)]-KD respectively, as compared with the wild-type B(1)R. Moreover, the substitution of the B(1) TM VII by its B(2) homologue TM increased the affinity for the pseudopeptide antagonists, Hoe140 and NPC 567. High affinity for desArg(10)-KD binding was fully regained when the B(2) residue Thr(287) was replaced in construct 6 by the corresponding B(1) Leu(294) residue. When the B(2) residue Tyr(295) was exchanged with the corresponding B(1) Phe(302), high affinity binding for both agonist and antagonist was recovered. Moreover, the L294T and F302Y mutant B(1)R exhibited 69- and 6.5-fold increases, respectively, in their affinities for the B(2) receptor antagonist, Hoe140. Therefore we proposed that Leu(294) and Phe(302) residues, which may not be directly involved in the binding of B(1)R ligands and, hence, their Thr(287) and Tyr(295) B(2) counterparts, are localized in a receptor region, which plays a pivotal role in the binding selectivity of the peptide or pseudopeptide kinin ligands.

Topics: Amino Acid Sequence; Animals; Binding Sites; Bradykinin; Bradykinin Receptor Antagonists; CHO Cells; Cricetinae; Humans; Inositol Phosphates; Kallidin; Molecular Sequence Data; Mutation; Peptides; Protein Binding; Quinolines; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, Bradykinin; Recombinant Fusion Proteins; Tetrahydroisoquinolines; Transfection

Prostaglandin (PG) release in cells expressing constitutive cyclooxygenase-1 is known to be regulated by liberation of arachidonic acid by phospholipase A2 followed by metabolism by cyclooxygenase. However, the relative contribution of phospholipase A2 to the release of PGs in cells expressing cyclooxygenase-2 is not clear. We addressed this question by using radioimmunoassay to measure PGE2 release by human cells (A549) induced to express cyclooxygenase-2 (measured by Western blot analysis) by interleukin-1beta. Cells were either unstimulated or stimulated with agents known to activate phospholipase A2 (bradykinin, Des-Arg10-kallidin, or the calcium ionophore A23187) or treated with exogenous arachidonic acid. When cells were treated to express cyclooxygenase-2, the levels of PGE2 released over 15 min were undetectable; however, in the same cells stimulated with bradykinin, A23187, or arachidonic acid, large amounts of prostanoid were produced. Using selective inhibitors/antagonists, we found that the effects of bradykinin were mediated by B2 receptor activation and that prostanoid release was due to cyclooxygenase-2, and not cyclooxygenase-1, activity. In addition, we show that the release of PGE2 stimulated by either bradykinin, A23187, or arachidonic acid was inhibited by the phospholipase A2 inhibitor arachidonate trifluoromethyl ketone. Hence, we have demonstrated that PGE2 is released by two components: induction of cyclooxygenase-2 and supply of substrate, probably via activation of phospholipase A2. This is illustrated in A549 cells by a clear synergy between the cytokine interleukin-1beta and the kinin bradykinin.

Topics: Adrenergic beta-Agonists; Adrenergic beta-Antagonists; Arachidonic Acid; Bradykinin; Calcimycin; Cell Line; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Dinoprostone; Humans; Inflammation; Interleukin-1; Isoenzymes; Kallidin; Membrane Proteins; Phospholipases A; Phospholipases A2; Prostaglandin-Endoperoxide Synthases; Receptors, Bradykinin

The elevation of intracellular [Ca2+] induced by bradykinin (Bk) was monitored with fura-2 fluorescence in human skin fibroblasts. Neither [des-Arg10][Leu9]kallidin nor D-Arg[Hyp3,Thi5,D-Tic7,Oic8]bradykinin (HOE140) inhibited the Ca2+ response stimulated by Bk. Moreover, each behaved as a partial agonist causing the elevation of intracellular [Ca2+].

Topics: Adolescent; Adrenergic beta-Antagonists; Bradykinin; Bradykinin Receptor Antagonists; Calcium; Cells, Cultured; Dose-Response Relationship, Drug; Fibroblasts; Humans; Kallidin; Male; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, Bradykinin; Skin

The effects of BK agonists and antagonists, and other hyperalgesic/antihyperalgesic drugs were measured (3 h after injection of hyperalgesic drugs) in a model of mechanical hyperalgesia (the end-point of which was indicated by a brief apnoea, the retraction of the head and forepaws, and muscular tremor). DALBK inhibited responses to carrageenin, bradykinin, DABK, and kallidin. Responses to kallidin and DABK were inhibited by indomethacin or atenolol and abolished by the combination of indomethacin + atenolol. DALBK or HOE 140, given 30 min before, but not 2 h after, carrageenin, BK, DABK and kallidin reduced hyperalgesic responses to these agents. A small dose of DABK+ a small dose of BK evoked a response similar to the response to a much larger dose of DABK or BK, given alone. Responses to BK were antagonized by HOE 140 whereas DALBK antagonized only responses to larger doses of BK. The combination of a small dose of DALBK with a small dose of HOE 140 abolished the response to BK. The hyperalgesic response to LPS (1 microg) was inhibited by DALBK or HOE 140 and abolished by DALBK + HOE 140. The hyperalgesic response to LPS (5 microg) was not antagonized by DALBK + HOE 140. These data suggest: (a) a predominant role for B2 receptors in mediating hyperalgesic responses to BK and to drugs that stimulate BK release, and (b) activation of the hyperalgesic cytokine cascade independently of both B1 and B2 receptors if the hyperalgesic stimulus is of sufficient magnitude.

Topics: Adrenergic beta-Antagonists; Animals; Atenolol; Bradykinin; Bradykinin Receptor Antagonists; Carrageenan; Dinoprostone; Dose-Response Relationship, Drug; Drug Synergism; Hyperalgesia; Indomethacin; Inflammation; Interleukin-8; Kallidin; Lipopolysaccharides; Male; Mice; Pain Measurement; Pain Threshold; Rats; Rats, Wistar; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, Bradykinin; Sheep; Time Factors; Tumor Necrosis Factor-alpha

In C9 rat liver cells bradykinin and kallidin increased (approximately 2-fold) the intracellular concentration of calcium, but the B1 agonist, des-Arg9-bradykinin did not. The effect of bradykinin was inhibited by the B2 antagonists, Hoe 140 and N-alpha-adamantaneacetyl-D-Arg-[Hyp3, Thi5,8, D-Phe7]-bradykinin, but not by the B1 antagonist, des-Arg9-[Leu8]-bradykinin. The action of bradykinin was diminished, but not abolished, in medium without calcium. The peptide was able to increase intracellular calcium concentration in cells treated with thapsigargin. Bradykinin action was not observed in cells previously stimulated with this local mediator: however, under the same conditions, angiotensin II induced a clear increase in intracellular calcium concentration. Our data indicate that activation of bradykinin B2 receptors increase intracellular calcium concentrations by inducing both gating of the cation and intracellular mobilization in C9 liver cells. In addition, homologous desensitization was observed.

Topics: Angiotensin II; Animals; Bradykinin; Calcium; Cell Line; Enzyme Activation; Kallidin; Liver; Rats; Receptor, Bradykinin B2; Receptors, Bradykinin; Thapsigargin

An increased response to the activation of receptors mediating excitatory effects may be involved in some forms of epilepsy. In this study, it has been tested whether B1 bradykinin receptors (which mediate excitatory effects in the peripheral nervous system and have little constitutional expression in the central nervous system) may be proposed in this role. Two experimental models of epilepsy (kindling and kainate) have been employed, and glutamate outflow experiments have been performed in hippocampal and cortical slices taken from control, kindled and kainate-treated rats. The endogenous B1 receptor agonist Lys-des-Arg9-bradykinin (10(-7) M) did not affect electrically-evoked glutamate overflow in control animals, but concentration-dependently increased it in kindled rats (maximal effect +40 to + 50%) and, to a lesser extent (+20%), in kainate-treated rats. These effects were fully prevented by the selective B1 receptor antagonist R-715 (10(-6) M), but not by the selective B2 receptor antagonist Hoe 140 (10(-6) M). The observed changes in B1 bradykinin receptor biological activity may play a role in epileptic hyperexcitability.

Topics: Animals; Bradykinin; Bradykinin Receptor Antagonists; Cerebral Cortex; Electric Stimulation; Epilepsy; Glutamic Acid; Hippocampus; In Vitro Techniques; Kainic Acid; Kallidin; Kindling, Neurologic; Male; Osmolar Concentration; Rats; Rats, Sprague-Dawley; Receptors, Bradykinin

The effects of selected bradykinin receptor antagonists on leukocyte infiltration into the lungs were studied in a model of guinea pig lung inflammation induced by the intravenous injection of Sephadex beads. The bradykinin B1 receptor antagonist, [Leu8]desArg9-BK (40 mg kg(-1) 24 h(-1)) and the bradykinin B2 receptor antagonist, DArg[Hyp3,Thi5,DTic7,Oic8]BK (code name HOE 140; 4 mg kg(-1) 24 h(-1)), administered intravenously by osmotic pumps, significantly reduced eosinophil counts by 33% and 42% in bronchoalveolar fluid, respectively. HOE 140 decreased neutrophil counts by 35%. LysLys[Hyp3,Igl5,D-Igl7,Oic8]desArg9BK+ ++ (code name B 9858), a newly described bradykinin B1 receptor antagonist, administered intraperitoneally (1 mg kg(-1)), decreased eosinophil and neutrophil counts by 45% in bronchoalveolar fluid. D-Arg[Hyp3,Igl5,D-Igl7,Oic8]BK (code name B 9430), a non-selective bradykinin B1/B2 receptor antagonist, also administered intraperitoneally (1 mg kg(-1)), decreased eosinophil and macrophage counts by 62% and 80% in bronchoalveolar fluid. These results suggest that bradykinin B1 and B2 receptors are involved in leukocyte recruitment in our model of lung inflammation.

Topics: Animals; Bradykinin; Bradykinin Receptor Antagonists; Bronchoalveolar Lavage Fluid; Cell Count; Dextrans; Guinea Pigs; Indicators and Reagents; Inflammation; Kallidin; Leukocytes; Lung Diseases; Male; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, Bradykinin

The pharmacological properties of bradykinin receptors were characterized in rat cultured vascular smooth muscle cells (VSMCs) using [3H]-bradykinin as a ligand. Analysis of binding isotherms gave an apparent equilibrium dissociation constant (K(D)) of 1.2 +/- 0.2 nM and a maximum receptor density (Bmax) of 47.3 +/- 4.4 fmol/mg protein. The specific binding of [3H]-bradykinin to VSMCs was inhibited by the B2 receptor-selective agonists (bradykinin and kallidin) and antagonists ([D-Arg0, Hyp3, Thi5, D-Tic7, Oic8]-bradykinin (Hoe 140) and [D-Arg0, Hyp3, Thi(5,8), D-Phe7]-bradykinin) with an order of potency as kallidin = bradykinin = Hoe 140 > [D-Arg0, Hyp3, Thi(5,8), D-Phe7]-bradykinin, but not by a B1 receptor-selective agonist (des-Arg9-bradykinin) and antagonist ([Leu8, des-Arg9]-bradykinin). Stimulation of VSMCs by bradykinin produced a concentration-dependent inositol phosphate (IP) accumulation, and initial transient peak of [Ca2+]i with half-maximal responses (pEC50) were 7.53 and 7.69, respectively. B2 receptor-selective antagonists (Hoe 140 and [D-Arg0, Hyp3, Thi(5,8), D-Phe7]-bradykinin) significantly antagonized the bradykinin-induced responses with pK(B) values of 8.3-8.7 and 7.2-7.9, respectively. Pretreatment of VSMCs with pertussis toxin (100 ng/ml, 24 h) did not alter the bradykinin-induced inositol phosphate accumulation and [Ca2+]i changes in VSMCs. Removal of external Ca2+ led to a significant attenuation of responses induced by bradykinin. Influx of external Ca2+ was required for the bradykinin-induced responses, since Ca2+-channel blockers, nifedipine, verapamil, and Ni2+, partially inhibited the bradykinin-induced IP accumulation and Ca2+ mobilization. These results demonstrate that bradykinin stimulates phosphoinositide hydrolysis and Ca2+ mobilization via a pertussis toxin-insensitive G-protein in rat VSMCs. Bradykinin B2 receptors may be predominantly mediating IP accumulation and subsequently induction of Ca2+ mobilization may function as the transducing mechanism for bradykinin-stimulated contraction of vascular smooth muscle.

Topics: Animals; Aorta; Bradykinin; Calcium; Calcium Channel Blockers; Calcium Signaling; Cells, Cultured; Enzyme Activation; Inositol Phosphates; Kallidin; Muscle Contraction; Muscle Proteins; Muscle, Smooth, Vascular; Nifedipine; Pertussis Toxin; Phosphatidylinositol Diacylglycerol-Lyase; Phosphatidylinositols; Radioligand Assay; Rats; Rats, Sprague-Dawley; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, Bradykinin; Type C Phospholipases; Verapamil; Virulence Factors, Bordetella

The action of bradykinin was studied in rat-1 fibroblasts stably expressing alpha1b-adrenoceptors. It was observed that bradykinin and kallidin markedly increase cytosol calcium concentration, but that the B1 agonist, des-Arg9-bradykinin, only mimicked this effect to a minimal extent. Antagonists, selective for the B2 subtype, such as Hoe 140, blocked this effect of bradykinin and kallidin. Similarly, bradykinin and kallidin stimulated the production of inositol phosphates and B2 antagonists blocked their actions. The possibility that bradykinin could modulate alpha1b-adrenoceptors was studied. It was observed that bradykinin and kallidin increased alpha1b-adrenoceptor phosphorylation and that such effect was also blocked by Hoe 140. Interestingly, the ability of norepinephrine to increase intracellular calcium concentration was not altered by pretreatment of the cells with bradykinin, i.e. bradykinin induced alpha1b-adrenoceptor phosphorylation but this did not lead to receptor desensitization.

Topics: Animals; Bradykinin; Calcium; Cell Line; Cricetinae; Cytosol; Endothelins; Inositol Phosphates; Kallidin; Norepinephrine; Phosphorylation; Rats; Receptor, Bradykinin B2; Receptors, Adrenergic, alpha-1; Receptors, Bradykinin; Recombinant Proteins; Signal Transduction; Transfection

The positive chronotropic effect of bradykinin was investigated in the pithed rat preparation. Cumulative treatment with bradykinin (0.20 nmol/kg-6.59 mumol/kg, intravenous [i.v.]) caused a dose-dependent increase in heart rate (HR) by a maximum of 80 +/- 3.3 beats min-1. In contrast, the active metabolite of bradykinin and selective bradykinin B1-receptor agonist, [des-Arg9]-bradykinin did not influence the spontaneous frequency of beating. Propranolol alone reduced the bradykinin-induced increase in HR and a combination of propranolol with prazosin abolished the chronotropic effect of bradykinin. The selective bradykinin B2 receptor antagonist. Hoe 140, dose-dependently shifted the dose-response curves of bradykinin to the right, whereas the bradykinin B1 receptor antagonist, des-Arg10-[Leu9]-kallidin proved ineffective. From our experiments it may be concluded that bradykinin induces tachycardia in the pithed rat primarily by stimulating the sympathetic ganglia leading to the release of noradrenaline, which subsequently activates cardiac beta 1-adrenoceptors. The bradykinin-induced chronotropic effect is mediated by bradykinin B2-receptors, whereas B1-receptors appear not to be involved.

Topics: Adrenalectomy; Adrenergic alpha-1 Receptor Antagonists; Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Animals; Blood Pressure; Bradykinin; Bradykinin Receptor Antagonists; Decerebrate State; Heart Rate; Kallidin; Male; Rats; Rats, Wistar; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, Adrenergic

To characterize the kinin receptor subtype involved in the relaxation of human isolated corpus cavernosum (HCC) induced by bradykinin (BK), Lys-bradykinin (Lys-BK), Met-Lys-bradykinin (Met-Lys-BK) and des-Arg9-bradykinin, and to investigate whether the kinin-induced relaxation of HCC results from the stimulation of nonadrenergic, noncholinergic (NANC) neurons supplying the cavernosal tissue.. Excised HCC tissues were immediately placed in Krebs solution and kept at 4 degrees C until use (never > 24 h after removal). HCC was cut in strips of approximately 2 cm, suspended in a cascade system and superfused with oxygenated and warmed Krebs solution at 5 mL/min. After equilibration for approximately 90 min, noradrenaline (3 micromol/L) was infused to induce a submaximal contraction of the HCC strips. The release of cyclo-oxygenase products was prevented by infusing indomethacin (6 micromol/L). HCC strips were calibrated by injecting a single bolus of the nitrovasodilator glyceryl trinitrate (GTN) and the sensitivity of the tissues adjusted electronically to be similar. The agonists (kinins, histamine and acetylcholine) were injected as a single bolus (up to 100 microL) and the relaxation of HCC expressed as a percentage of the submaximal relaxation induced by GTN.. Bradykinin, Lys-BK and Met-Lys-BK significantly relaxed the HCC tissues; on a molar basis, there was no statistical difference among the degrees of relaxation induced by these peptides. The B1 kinin receptor agonist des-Arg9-bradykinin had no effect on the HCC. The infusion of the B2 kinin receptor antagonist Hoe 140 (50 nmol/L) virtually abolished the relaxation induced by BK, Lys-BK and Met-Lys-BK without affecting those induced by acetylcholine and histamine. The infusion of the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester increased the tone of the HCC tissues and significantly reduced (P < 0.01) the relaxation induced by BK (74%), Lys-BK (90%), Met-Lys-BK (87%) and acetylcholine (89%) without affecting those induced by GTN. The subsequent infusion of L-arginine (300 micromol/L) partially reversed the increased tone and significantly (P < 0.01) restored the relaxation induced by BK, Lys-BK and Met-Lys-BK. The results were similar with the novel guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,3,-alquinoxalin-1-one] which reduced by > 95% (P < 0.01) the relaxation induced by BK, Lys-BK, Met-Lys-BK, acetylcholine and GTN. The infusion of the sodium-channel blocker tetrodotoxin had no significant effect on the BK-, GTN- and acetylcholine-induced relaxation of HCC.. This study clearly showed the existence of functional B2 kinin receptors in human erectile tissues that when activated lead to the release of NO and hence relaxation of the HCC tissues. As tetrodotoxin failed to affect the kinin-induced relaxation of HCC strips, it is likely that these peptides release NO from the endothelium of sinusoidal capillaries rather than from neuronal sources supplying the cavernosal tissue. Although tissue kallikreins and their components have been found in the male reproductive system, the physiopathological importance of these findings has yet to be elucidated.

Topics: Adolescent; Adrenergic beta-Antagonists; Adult; Bradykinin; Bradykinin Receptor Antagonists; Enzyme Inhibitors; Humans; Kallidin; Male; Middle Aged; NG-Nitroarginine Methyl Ester; Nitric Oxide; Penile Erection; Penis; Receptors, Bradykinin

The present study has employed in vitro electrophysiology to characterise the ability of bradykinin to depolarise the rat isolated nodose ganglion preparation, containing the perikarya of vagal afferent neurons. Both bradykinin and kallidin elicited a concentration-dependent (1-100 nM) depolarisation when applied to the superfusate bathing the nodose ganglia, whereas the bradykinin B1 receptor agonist, des-Arg9-bradykinin, was only effective in the micromolar range. Furthermore, the electrophysiological response to bradykinin was antagonised by the bradykinin B2 receptor antagonist, D-arginyl-L-arginyl-L-prolyl-trans-4-hydroxy-L-prolylglycyl-3-(2-t hienyl)-L-alanyl-L-seryl-D-1,2,3,4-tetrahydro-3-isoquinolinecarbonyl+ ++-L-(2alpha,3beta,7abeta)-octahydro-1H-indole-2-carbonyl-L- arginine (Hoe 140), in a concentration-related manner. To determine the anatomical location of functional bradykinin B2 receptors, in vitro autoradiography with [125I]para-iodophenyl Hoe 140 was performed on sections of rat and human inferior vagal (nodose) ganglia and confirmed the presence of binding over vagal perikarya. Collectively, these data provide evidence for functionally relevant bradykinin B2 receptors on vagal afferent neurons, which are apparently also present on human vagal perikarya.

Topics: Adrenergic beta-Antagonists; Animals; Autoradiography; Bradykinin; Bradykinin Receptor Antagonists; Electrophysiology; Humans; Kallidin; Male; Neurons, Afferent; Nodose Ganglion; Rats; Rats, Sprague-Dawley; Receptor, Bradykinin B2; Receptors, Bradykinin; Vasodilator Agents

This study investigates the effect and some of the mechanisms involved following systemic treatment of mice with Mycobacterium bovis bacillus Calmette-Guérin (BCG) (1 dose per animal containing 6.4 x 10(4) colony-forming units (CFu) 20-60 days beforehand) on modulation of the kinin B1 receptor agonist-induced nociception and oedema formation in the formalin test. Intraplantar (i.p.l.) co-injection of des-Arg9-bradykinin (4-32 nmol/paw) or des-Arg10-kallidin (1-15 nmol/paw), together with sub-maximal concentrations of formalin (0.01 or 0.5%), potentiated (P < 0.01) both pain phases and the paw oedema caused by formalin in animals pre-treated with saline. However, when animals were pre-treated with BCG, the dose-response curves for both B1 agonists were shifted 2 to 8-fold to the left. These B1-mediated effects peaked at 30-45 days after BCG treatment and were still elevated at 60 days after BCG injection. The pain response and oedema formation caused by i.p.l. co-injection of des-Arg9-bradykinin, together with formalin in BCG-pre-treated animals, were dose-dependently antagonised by i.p.l. co-injection of the B1 antagonist des-Arg9[Leu8]bradykinin (1-15 nmol/paw), but were not affected by the B2 antagonist Hoe 140 (10 nmol/paw). The i.p.l. co-injection of tyrosine8-bradykinin (a B2 agonist, 3-15 nmol/paw) with formalin (0.01 or 0.5%) potentiated the pain response and paw oedema in BCG and saline-pre-treated animals to the same extent (P < 0.01). The actions caused by tyrosine8-bradykinin were antagonised by Hoe 140, while des- Arg9[Leu8]bradykinin (10 nmol/paw) had no effect. Dexamethasone (0.5 mg/kg, s.c.), given every 24 h, from day 0 to 30-45, inhibited significantly the potentiation of nociceptive response and oedema formation caused by i.p.l. co-injection of formalin plus des-Arg9-bradykinin, while indomethacin (2 mg/kg, i.p.) or phenidone (30 mg/kg, i.p.), given 1 h prior, caused less inhibition. These data show that the long-term systemic treatment of mice with BCG produced dose-related potentiation of B1 receptor agonist-mediated nociception and oedema formation, without affecting similar responses caused by the B2 receptor agonist tyrosine8-bradykinin. Thus, systemic treatment of mice with BCG induces upregulation of B1 receptors, without affecting B2-mediated responses, by a mechanism that seems to be secondary to cytokine release.

Topics: Animals; Bradykinin; Dexamethasone; Dose-Response Relationship, Drug; Drug Synergism; Edema; Formaldehyde; Hindlimb; Indomethacin; Kallidin; Male; Mice; Mycobacterium bovis; Pain; Pain Measurement; Pyrazoles; Receptor, Bradykinin B1; Receptors, Bradykinin

Responses to T-kinin, a peptide formed from the acute-phase substrate T-kininogen, were investigated in the hindlimb vascular bed of the cat. Under constant-flow conditions, injections of T-kinin into the perfusion circuit in doses of 0.03-1 nmol induced rapid dose-related decreases in perfusion pressure. Responses to T-kinin were similar in time course and magnitude to responses to bradykinin and kallidin and were inhibited by the kinin B2-receptor antagonist, Hoe-140. Responses to T-kinin were attenuated by an inhibitor of nitric oxide synthase and by tetraethylammonium chloride and were enhanced in duration by the guanosine 3',5'-cyclic monophosphate (cGMP) phosphodiesterase inhibitor zaprinast. Responses to T-kinin were not altered by inhibitors of K+(ATP) channels, by the cyclooxygenase pathway, or by muscarinic or beta-adrenergic-receptor antagonists. These data suggest that vasodilator responses to T-kinin are mediated by kinin B2-receptor-stimulated release of nitric oxide from the endothelium and increased smooth muscle cGMP levels. These results indicate that activation of K+(ATP) channels and muscarinic or beta-adrenergic receptors and the release of vasodilator prostaglandins are not involved in mediating the response to T-kinin in the hindlimb circulation of the cat.

Topics: Acetylcholine; Albuterol; Angiotensin-Converting Enzyme Inhibitors; Animals; Bradykinin; Bradykinin Receptor Antagonists; Cats; Enalaprilat; Endothelium, Vascular; Female; Hindlimb; Hydrazines; Kallidin; Male; Muscle, Skeletal; Muscle, Smooth, Vascular; NG-Nitroarginine Methyl Ester; Nitrogen Oxides; Penicillamine; Regional Blood Flow; S-Nitroso-N-Acetylpenicillamine; Tetraethylammonium; Tetraethylammonium Compounds; Vasodilation; Vasodilator Agents

Previous studies have demonstrated that transient ischemia inhibits the release of norepinephrine (NE) following a sustained ischemia. However, the mechanism underlying this inhibition is unknown. Therefore, this study was designed to investigate whether bradykinin (BK) may be involved in the inhibition of NE release following ischemic preconditioning. The effects of transient ischemia, exogenous BK, and kinin receptor blockers on NE release after a prolonged ischemia were tested in the isolated rat heart preparation. Three cycles of 5-min ischemia and reperfusion resulted in the reduction of NE release from 115.3 +/- 14.5 to 51.6 +/- 9.3 pmol.g-1 (p < 0.05) after 30 min of subtotal global ischemia. This effect was not prevented by the administration of either Lys-[Leu8]-des-Arg9-BK (1 mumol.L-1), a B1 antagonist, or HOE-140 (1 mumol.L-1), a B2 antagonist. Three cycles of 5-min BK or des-Arg9-BK infusion also resulted in a dose-dependent inhibition of NE release after 30 min of ischemia. The inhibitory effects of BK (1 mumol.L-1) or des-Arg9-BK (0.5 mumol.L-1) were blocked by Lys-[Leu8]-des-Arg9-BK (1 mumol.L-1), but not by HOE-140 (1 mumol.L-1). The results show that transient ischemia and BK protect sympathetic nerve endings in the isolated rat heart. The inhibition of NE release by pretreatment with BK is mediated by the activation of B1 receptors, whereas preconditioning provided by transient ischemia may be mediated by a different, yet unknown, mechanism in the rat heart.

Topics: Animals; Bradykinin; Heart; Kallidin; Male; Myocardial Ischemia; Myocardial Reperfusion; Norepinephrine; Rats; Rats, Wistar; Receptors, Tachykinin

Topics: Bradykinin; Humans; Ileum; In Vitro Techniques; Kallidin; Muscle Contraction; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, Bradykinin

1. The ability of bradykinin and its analogues to depolarize rat and mouse superior cervical ganglia was studied by use of in vitro grease-gap recording techniques, and the ability of antagonists selective for bradykinin receptor subtypes to block their effects was examined. 2. Bradykinin (3 microM) depolarized ganglia from both species, although the magnitude of the maximal response was less in mouse (15 +/- 5%, n = 7) than rat tissue (33 +/- 6%, n = 7), relative to muscarine (1 microM). 3. Interleukin 1 beta (30 u ml-1 for 18 h at 37 degrees C) increased the depolarization caused by bradykinin (3 microM) in mouse ganglia from 15% to 54% (P < 0.001, n = 12). Responses to the B1 receptor agonist, [des-Arg10]-kallidin (3 microM) were similarly potentiated but this was only detected after inhibition of peptidase activity with 10 microM captopril (4% to 35%, n = 5). 4. In ganglia from both species the rank order of agonist potency was bradykinin = [Lys0]-bradykinin >> [des-Arg10]-kallidin. However, like responses to [des-Arg10]-kallidin in mouse tissue, both the potency of bradykinin and the maximal depolarization achieved (EC50 = 912 nM; 80%, n = 11) was enhanced following inhibition of angiotensin converting enzyme with 10 microM captopril (EC50 = 50 nM; 135%, n = 4). 5. Responses to bradykinin were selectively antagonized by the B2 receptor antagonist, Hoe 140 but not by the B1 antagonist, [Leu8]-bradykinin1-8. From Schild analysis the pA2 value for Hoe 140 in mouse tissue was 9.65, although the slope of the regression line was significantly greater than unity, indicating non-competitive kinetics (slope = 1.88 +/- 0.18, n = 9). The depolarization caused by [Lys0]-bradykinin was also antagonized by Hoe 140 (3 nM).6. Thus the predominant bradykinin receptor in mouse superior cervical ganglia is compatible with a B2 subtype. Furthermore the depolarizations caused by B1 and B2 agonists in this tissue can be increased following exposure to interleukin l beta, and by blocking peptide degradation with captopril.

Topics: Amino Acid Sequence; Animals; Bradykinin; Bradykinin Receptor Antagonists; Electrophysiology; Interleukin-1; Kallidin; Male; Mice; Molecular Sequence Data; Muscarine; Rats; Rats, Sprague-Dawley; Receptors, Bradykinin; Structure-Activity Relationship; Superior Cervical Ganglion

The present study was undertaken to characterize the direct chronotropic effect of bradykinin in isolated spontaneously beating atria of the guinea pig. Bradykinin caused concentration-dependent increases in the beating rate of atria. In contrast, the active metabolite of bradykinin and the typical bradykinin B1 receptor agonist, Des-Arg9-bradykinin, had no effect on the beating rate of atria. Inhibition of converting enzyme or neutral endopeptidase by captopril or SQ-28603, respectively, did not affect beating rate but potentiated bradykinin-induced increase in beating rate. The potent bradykinin B2 receptor antagonist, HOE 140, antagonized bradykinin-induced chronotropic effect. In contrast, the bradykinin B1 receptor antagonist, Lys-[Leu8]Des-Arg9-bradykinin, had no effect. The increase in beating rate caused by bradykinin was not affected by blockade of beta 1-adrenoceptors, cyclooxygenase, or nitric oxide synthesis using atenolol, indomethacin and N omega-nitro-L-arginine, respectively. Unlike bradykinin, angiotensin I and angiotensin II caused very small or no change in beating rate in the presence or absence of captopril and SQ-28603. These results indicate that bradykinin causes a direct positive chronotropic effect which is mediated by activation of bradykinin B2 receptors independently of prostaglandins and beta 1-adrenoceptors.

Topics: Adrenergic beta-Agonists; Alanine; Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Atrial Function; Bradykinin; Bradykinin Receptor Antagonists; Captopril; Enzyme Inhibitors; Guinea Pigs; Heart; Heart Atria; Heart Rate; In Vitro Techniques; Kallidin; Male; Myocardium; Nitric Oxide; Prostaglandins; Receptor, Bradykinin B2; Receptors, Bradykinin; Sensitivity and Specificity

Bradykinin (BDK)-induced increases in intracellular Ca2+ concentration ([Ca2+]i) were monitored in cultured canine tracheal smooth muscle cells (TSMCs) using a fluorescent Ca2+ indicator, Fura-2. BDK and kallidin caused an initial transient peak followed by a sustained elevation of [Ca2+]i in a concentration-dependent manner, with half-maximal stimulation (log EC50) obtained at -8.10 M and -8.04 M, respectively. The BDK-induced rise in [Ca2+]i was not affected by the BDK B1 receptor antagonist, des-Arg9[Leu8]-BDK (10 microM). However, the BDK B2 receptor antagonists des-Arg[Hyp3, Thi5,8, D-Phe7]-BDK and Hoe 140 had high affinity in antagonizing BDK with pKB values of 7.5 +/- 0.3 and 8.7 +/- 0.3, respectively. The sustained phase of the rise in [Ca2+]i was dependent on the presence of external Ca2+, as evidenced by a decline to the resting level on addition of EGTA. In the absence of external Ca2+, only an initial transient peak was seen which then declined to the resting level; a sustained elevation of [Ca2+]i could then be evoked by addition of 1.8 mM Ca2+ in the continued presence of BDK. Ca2+ influx was required for the changes in [Ca2+]i, since Ca(2+)-channel blockers, diltiazem, verapamil, and Ni2+, decreased both the initial and sustained elevation of [Ca2+]i in response to BDK. In conclusion, these findings indicate that the initial increase in [Ca2+]i stimulated by BDK acting on BDK B2 receptors is due to the release of Ca2+ from internal stores, followed by the influx of external Ca2+ into the cells. The influx of extracellular Ca2+ partially involves a diltiazem- and verapamil-sensitive Ca2+ channel.

Topics: Animals; Bradykinin; Calcium; Carbachol; Cells, Cultured; Diltiazem; Dogs; Dose-Response Relationship, Drug; Egtazic Acid; Female; Fura-2; Kallidin; Male; Muscle, Smooth; Trachea; Verapamil

Kinin B1 receptors on rabbit aorta smooth muscle cells in culture were investigated. [3H]Des-Arg10-kallidin labeled a single site in cells at early passage with an equilibrium dissociation constant of 258 pM and a maximal binding density of approximately 680 sites/cell. Treatment of the same cells for 18 h with epidermal growth factor increased the binding density over 6-fold without affecting the ligand's affinity. At latter passages, the density of binding sites was found to increase and the growth factor had a much less pronounced effect. The rank order of potencies for agonist inhibition of binding (des-Arg10-kallidin > des-Arg9-BK = kallidin > bradykinin) was consistent with the specific labeling of a B1 receptor. Also, [3H]des-Arg10-kallidin binding was potently inhibited by the B1 receptor antagonist des-Arg9[Leu8]bradykinin but not by the B2 receptor antagonist Hoe 140. The agonists were found to stimulate phosphoinositide hydrolysis in the smooth muscle cells with an order of potencies that reflected their binding assay activities. Des-Arg9[Leu8] BK blocked the des-Arg10-kallidin response with a potency consistent with its known B1 receptor activity while Hoe 140 was inactive. These results demonstrate the presence of inducible B1 receptors on rabbit aorta smooth muscle cells in culture that couple to phospholipase C activation. These cells should be useful in future studies of the mechanisms and factors involved in the regulation of expression of the B1 receptor.

Topics: Animals; Aorta; Binding Sites; Binding, Competitive; Bradykinin; Cells, Cultured; Enzyme Activation; Hydrolysis; Kallidin; Lysophospholipase; Muscle, Smooth, Vascular; Phosphatidylinositols; Rabbits; Receptors, Bradykinin

1. Hoe-140, a potent kinin receptor antagonist, was investigated for its ability to inhibit the effects of lysylbradykinin (kallidin) on a cultured colonic epithelium, HCA-7 Colony 29, derived from a human adenocarcinoma. 2. Measurements of electrogenic chloride secretion (as short circuit current), and of intracellular Ca2+ (from Fura-2 fluorescence) were used to assess the action of lysylbradykinin in the absence and presence of Hoe 140. 3. From short circuit current data, Hoe 140 appeared to be a competitive antagonist with a Ki value of 5 nM. However, with measurements of intracellular Ca2+ Hoe 140 was apparently a non-competitive antagonist with a Ki of between 4-6 nM. 4. Because of the unexpected finding of non-competitive antagonism, measurements were made with a second antagonist pair, histamine and mepyramine. Mepyramine behaved as a competitive antagonist against responses to histamine with a Ki value of approximately 5 nM when short circuit current measurements were evaluated. However, when intracellular Ca2+ concentration was used as a measure mepyramine, 30 nM, produced a near parallel shift in the response curve, but at 100 nM the maximal response was depressed. 5. The reasons why the apparent type of antagonism depends upon the method of measurement is discussed, bearing in mind that the increase in intracellular Ca2+ is a signal which precedes the increase in short circuit current.

Topics: Adenocarcinoma; Binding, Competitive; Bradykinin; Calcium; Chlorides; Colonic Neoplasms; Epithelium; Fura-2; Histamine; Humans; Ion Channels; Kallidin; Kinins; Pyrilamine; Tumor Cells, Cultured

Topics: Bradykinin; Humans; Hypotension; Kallidin; Kallikreins; Muscle Contraction; Muscle, Smooth; Oligopeptides