Comparative nasal effects of bradykinin, kallidin and [Des-Arg9]-bradykinin in atopic rhinitic and normal volunteers

The temporal relationship between the neural and vascular actions of kallidin within the nose

The time course of effect of the B₂-receptor agonist kallidin (K) on induced changes of nasal airflow, rhinorrhoea, nasal pain, sneezing and nasal microvascular leakage has been examined and compared with its B₂ metabolite agonist bradykinin (B) and the B₁-agonist [des-arg⁹]-bradykinin (D). When administered as a single dose K and B induced an immediate sensation of pain, rhinorrhoea, elevations in lavage albumin and protein levels and a sustained increase in nasal airways resistance (NAR) for 5–40 min post-challenge. [des-arg⁹]-Bradykinin and vehicle placebo (V) were without effect on any of these indices. These studies identify the action of K and B within the nose and differentiate the neural and vascular effects of these kinins in addition to suggesting the potential that nasal blockage and nasal microvascular leakage represent alterations in differing vascular compartments. These findings have implications for the understanding and therapeutic manipulation of rhinitis.

The role of kinin B1 and B2 receptors in the scratching behaviour induced by proteinase-activated receptor-2 agonists in mice

BACKGROUND AND PURPOSE

Activation of the proteinase-activated receptor-2 (PAR-2) induces scratching behaviour in mice. Here, we have investigated the role of kinin B(1) and B(2) receptors in the pruritogenic response elicited by activators of PAR-2.

EXPERIMENTAL APPROACH

Scratching was induced by an intradermal (i.d.) injection of trypsin or the selective PAR-2 activating peptide SLIGRL-NH(2) at the back of the mouse neck. The animals were observed for 40 min and their scratching response was quantified.

KEY RESULTS

I.d. injection of trypsin or SLIGRL-NH(2) evoked a scratching behaviour, dependent on PAR-2 activation. Mice genetically deficient in kinin B(1) or B(2) receptors exhibited reduced scratching behaviour after i.d. injection of trypsin or SLIGRL-NH(2). Treatment (i.p.) with the non-peptide B(1) or B(2)receptor antagonists SSR240612 and FR173657, respectively, prevented the scratching behaviour caused by trypsin or SLIGRL-NH(2). Nonetheless, only treatment i.p. with the peptide B(2)receptor antagonist, Hoe 140, but not the B(1)receptor antagonist (DALBK), inhibited the pruritogenic response to trypsin. Hoe 140 was also effective against SLIGRL-NH(2)-induced scratching behaviour when injected by i.d. or intrathecal (i.t.) routes. Also, the response to SLIGRL-NH(2) was inhibited by i.t. (but not by i.d.) treatment with DALBK. Conversely, neither Hoe 140 nor DALBK were able to inhibit SLIGRL-NH(2)-induced scratching behaviour when given intracerebroventricularly (i.c.v.).

CONCLUSIONS AND IMPLICATIONS

The present results demonstrated that kinins acting on both B(1) and B(2) receptors played a crucial role in controlling the pruriceptive signalling triggered by PAR-2 activation in mice.

Kinins are involved in the development of allergic nasal hyperresponsiveness in guinea pigs

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.

Chemical response pattern of different classes of C-nociceptors to pruritogens and algogens

Vasoneuroactive substances were applied through intradermal microdialysis membranes and characterized as itch- or pain-inducing in psychophysical experiments. Histamine always provoked itching and rarely pain, capsaicin always pain but never itching. Prostaglandin E(2) (PGE(2)) led preferentially to moderate itching. Serotonin, acetylcholine, and bradykinin induced pain more often than itching. Subsequently the same substances were used in microneurography experiments to characterize the sensitivity profile of human cutaneous C-nociceptors. The responses of 89 mechanoresponsive (CMH, polymodal nociceptors), 52 mechanoinsensitive, histamine-negative (CMi(His-)), and 24 mechanoinsensitive, histamine-positive (CMi(His+)) units were compared. CMi(His+) units were most responsive to histamine and to PGE(2) and less to serotonin, ACh, bradykinin, and capsaicin. CMH units (polymodal nociceptors) and CMi(His-) units showed significantly weaker responses to histamine, PGE(2), and acetylcholine. Capsaicin and bradykinin responses were not significantly different in the two classes of mechano-insensitive units. We conclude that CMi(His+) units are "selective," but not "specific" for pruritogenic substances and that the pruritic potency of a mediator increases with its ability to activate CMi(His+) units but decreases with activation of CMH and CMi(His-) units.

Nitric oxide attenuates platelet-activating factor induced nasal airway plasma extravasation in healthy subjects

BACKGROUND

Paranasal sinuses and the nose are important sources of nitric oxide (NO) in humans but the relevance of NO production to the control of nasal airway plasma exudation and its response to inflammatory mediators such as platelet-activating factor (PAF) in healthy subjects is not well known.

DESIGN

In this study we aimed to evaluate the effect of the nitric oxide synthase (NOS) inhibitor NG L-arginine methyl ester (L-NAME) on nasal airway plasma extravasation at baseline and after an acute challenge with PAF that induces most symptoms of rhinitis. Eleven healthy subjects were enrolled in the study. Plasma extravasation in the nasal airway was assessed by measuring the albumin content of nasal lavage.

RESULTS

PAF challenge caused a significant increase in concentrations of albumin in the nasal lavage fluid (from 0.59 +/- 0.13 mg dL(-1) to 2.46 +/- 0.45 mg dL(-1)) after placebo. Pretreatment with L-NAME significantly prevented the increase of albumin in the nasal lavage fluid induced by PAF as compared to placebo (from 0.53 +/- 0.11 mg dL(-1) to 1.70 +/- 0.28 mg dL(-1); P < 0.005).

CONCLUSION

Topical administration of a NO inhibitor is able to attenuate the nasal airway plasma extravasation induced by PAF, suggesting that NO release in vivo is involved in the nasal response to PAF.

Allergic rhinitis: not purely a histamine-related disease

Allergic rhinitis is an inflammatory disorder of the nasal mucosa typified by the symptoms of nasal itch, sneeze, anterior nasal secretions, and nasal blockage. These symptoms arise from the interaction between mediators and neural, vascular, and glandular structures within the nose. Nasal itch, sneezes, and rhinorrhoea are predominantly neural in origin, while nasal obstruction is predominantly vascular. Nasal biopsy studies show accumulation of eosinophils within the lamina propria and epithelium and an increase in tissue and cell surface basophils in both seasonal and perennial allergic rhinitis. These cells are in an activated state. Within the epithelium, increased numbers of mast cells, T cells and Langerhans' cells, which induce T-cell activation, are found. The accumulation of these cells can be linked to chemokine and cytokine generation by the epithelial cells themselves. Thus, the tissue cell recruitment is orchestrated by activated mast cells, T cells, and epithelial cells, with the recruited tissue eosinophils also contributing to their persistence at this site through autocrine mechanisms. Mast cells generate an array of mediators including histamine, tryptase, leukotrienes, and prostaglandins. Histamine is also generated by basophils. Eosinophils and basophils contribute to the leukotriene synthesis within the tissue. Histamine nasal insufflation induces nasal itch, sneeze, and rhinorrhoea as well as nasal blockage, thereby reproducing all the symptoms of allergic rhinitis. These effects are primarily mediated by H1-receptors, and H1-receptor antagonists are a prominent treatment. Antagonism of histamine at these receptors reduces symptoms by about 40-50%, with the greatest effect on the neurally mediated responses. Thus, histamine is a major mediator of allergic rhinitis, but not the sole contributor. Nasal insufflation with leukotrienes, prostaglandins, or kinins is associated with the development of nasal blockage. These mediators act primarily on the nasal vasculature and, in this respect, leukotrienes are potent mediators. Leukotrienes also induce plasma protein exudation, which contributes to the anterior nasal secretions. Studies with combination products have suggested that modifying the effects of both leukotrienes and histamine has complementary effects in relieving nasal symptoms, indicating that both these mediators are relevant to disease expression.

Involvement of kinins in hyperresponsiveness induced by platelet activating factor in the human nasal airway

1. The aim of this study was to investigate the role of kinins in the development of nasal hyperresponsiveness induced by platelet activating factor (PAF) in normal human subjects. 2. Intranasal administration of PAF, 60 micrograms, induced an increased responsiveness to histamine, 200 micrograms per nostril, 6 h later. This effect was abolished by pretreatment with the bradykinin B2 receptor antagonists icatibant and [1-adamantaneacetyl-D-Arg0,Hyp3,beta-(2-thienyl)-Al a5,8,D-Phe7]-bradykinin ([Ad]-BK), both at 200 micrograms, every 2 h following PAF administration. 3. In a separate experiment, utilizing the same protocol, nasal lavage was used to measure the release of mediators into the nasal cavity following treatment with PAF. PAF increased the levels of eosinophil cationic protein (ECP) and kinin detected in the lavage samples, compared with a saline control. The levels of these mediators were reduced by pretreatment with either icatibant or [Ad]-BK. 4. Administration of lyso-PAF, 60 micrograms intranasally, did not cause a rise in kinin or ECP levels in nasal lavage fluid. 5. Exogenous bradykinin, 500 micrograms, or a saline control, applied topically to the nasal mucosa every 30 min for 2 h, failed to cause hyperresponsiveness to histamine. 6. We conclude that bradykinin itself does not cause hyperresponsiveness, but is involved in the hyperresponsiveness induced by PAF in the human nasal airway.

The kinin system in rhinitis and asthma

The past decade has seen renewed interest in the potential role of kinins in airway diseases. The correlation between kinin generation and symptoms of inflammation, together with the demonstration that administration of kinins to the airway mucosa can induce relevant symptoms, provides strong circumstantial support for a role of kinins in the pathogenesis of airway diseases, such as allergic and viral rhinitis and asthma. Definitive studies of the effects of blockade of kinin actions on symptomatic responses, however, are still needed. The effects of kinins in the airways, and the mechanisms by which they exert their actions clearly vary depending on the presence of inflammation in the airways. Although a growing body of evidence implicates activation of sensory nerves as an important component of kinin effects in inflamed airways, the components of inflammation that modify the response of these sensory nerves, the mechanisms by which neuronal responsiveness alters, and the degree of selectivity of neuronal activation to bradykinin are all topics that require further delineation.

Airway neural responses to kinins: tachyphylaxis and role of receptor subtypes

To further define the role of neural responses in the hyperreactivity of inflamed human upper airways to bradykinin (BK), we determined if repeated challenges with BK led to tachyphylaxis of neurally mediated responses in subjects with perennial allergic rhinitis. We also tested the hypothesis that enhanced reactivity to kinins in inflamed airways was caused by induction of B1-kinin receptors by comparing the effects of the selective B1-receptor agonist, des-Arg10-lysylbradykinin, and the B2 receptor agonist, BK, in the lower airways of asthmatics and in the upper airways of subjects with perennial allergic rhinitis. Repeated BK challenges led to tachyphylaxis of sneezing and of neurally mediated serous glandular secretion in subjects with perennial allergic rhinitis. Surprisingly, tachyphylaxis of increased local vascular permeability was also observed. By contrast, repeated challenges with BK in normal subjects led to reproducible increases in vascular permeability. Provocation with des-Arg10-lysylbradykinin did not cause bronchoconstriction in asthmatic subjects or increase glandular secretion or vascular permeability in the upper airways of subjects with rhinitis. We conclude that increased reactivity to kinins in inflamed human airways is mediated, at least in part, by neural reflexes, and is not caused by induction of B1-receptors.

Aminopeptidase activity in human nasal mucosa

BACKGROUND

Aminopeptidases activate bradykinin and degrade many inflammatory peptides.

OBJECTIVE

The objective of this study was to identify the types of aminopeptidase activities in human nasal mucosa.

METHODS

Human nasal mucosa was homogenized (n = 12), and cytoplasmic (S2) and membrane-rich (P2) fractions were obtained. Several aminopeptidase (Ap) activities were defined by (1) substrate specificity with leucine-enkephalin (leu-Ap) and alanine-nitroanilide (ala-Ap), (2) inhibitor studies with puromycin and bestatin, (3) enzyme activity histochemistry (zymography), (4) immunohistochemistry, and (5) gel electrophoresis. Human volunteers had methacholine, histamine, and allergen nasal provocations to determine the mechanisms controlling nasal aminopeptidase secretion in vivo.

RESULTS

P2 was the largest reservoir of puromycin-resistant aminopeptidase activity (630 pmol leu-enk/min/mg protein). S2 contained 32 pmol leu-enk/min/mg activity, with 80% representing puromycin-resistant activity and 20% puromycin-sensitive aminopeptidase (PS-Ap). Ala-Ap was detected in both P2 and S2 fractions and was localized by zymography to epithelial and gland cells. Anti-rat brain-soluble PS-Ap IgG detected immunoreactive material in epithelium, glands, and endothelium. In nasal provocation studies, leu-AP correlated with glandular exocytosis but not vascular leak.

CONCLUSIONS

The predominant aminopeptidase in human nasal epithelial and submucosal gland cells was membrane-bound puromycin-resistant aminopeptidase. A novel soluble puromycin-resistant aminopeptidase and lower amounts of soluble PS-Ap were also detected.

Exposing guinea pigs to ozone for 1 wk enhances responsiveness of rapidly adapting receptors

Acute exposure to ozone causes changes in breathing pattern and lung function which may be caused in part by stimulation of rapidly adapting receptors (RARs). The consequences of repeated daily ozone exposure on RAR responsiveness are unknown, although ozone-induced changes in pulmonary function diminish with repeated exposure. Accordingly, we investigated whether repeated daily ozone exposure diminishes the general responsiveness of RARs. Guinea pigs (n = 30) were exposed to 0.5 parts/million ozone or filtered air (8 h/day for 7 days). The animals were then anesthetized, and RAR impulse activity, dynamic compliance (Cdyn), and lung resistance were recorded at baseline and in response to four stimuli: substance P, methacholine, hyperinflation, and removal of positive end-expiratory pressure. Repeated daily ozone exposure exaggerated RAR responses to substance P, methacholine, and hyperinflation without causing physiologically relevant effects on baseline or substance P- and methacholine-induced changes in Cdyn and lung resistance. Because agonist-evoked changes in RAR activity preceded Cdyn changes, the data suggest that repeated daily ozone exposure enhances RAR responsiveness via a mechanism other than changes in Cdyn.

Inflammatory mediators in naturally occurring rhinitis

BACKGROUND

The mediators released during the allergic inflammatory reaction induce the clinical symptoms of the allergic disease and although there have been numerous studies investigating mediator release in allergen challenge models of allergic rhinitis very few have extended this approach to the study of natural disease.

OBJECTIVE

The aim of this investigation was therefore to measure mast cell and eosinophil mediator levels and indices of vascular permeability in naturally occurring rhinitis.

METHODS

Three groups of subjects were studied, normal non-rhinitics, seasonal allergic rhinitics in and out of the grass pollen season and perennial allergic rhinitics. Mediators were recovered using the technique of nasal lavage and the levels of tryptase, histamine, eosinophil cationic protein and albumin were determined. In addition, eosinophils were enumerated in nasal smears as an indices of underlying inflammation.

RESULTS

The levels of tryptase, eosinophil cationic protein and albumin were significantly higher in the lavage recovered from the symptomatic seasonal allergic rhinitics than when asymptomatic (P = 0.05, P = 0.003, P = 0.009, respectively). These levels of eosinophil cationic protein and albumin were also significantly higher than those of the normal non-rhinitics (P = 0.0008, P = 0.0.003, respectively). In the perennial allergic rhinitics the levels of tryptase, eosinophil cationic protein and albumin were higher than the normal non-rhinitics (P < 0.0001, P = 0.0003, P = 0.0001, respectively). The levels of tryptase and histamine were higher in the perennial allergic rhinitics than the seasonal allergic rhinitics (P = 0.0003, P = 0.006, respectively). These changes in mediator levels were accompanied by a significant influx of eosinophils into the nasal mucosa of both the symptomatic seasonal rhinitics, compared with asymptomatic (P = 0.04) and normal controls (P = 0.0006) and the perennial rhinitics compared to normal controls (P = 0.03).

CONCLUSION

These results indicate that in both naturally occurring seasonal allergic rhinitis and perennial allergic rhinitis mast cell and eosinophil activation occurs and this is accompanied by an increase in vascular permeability. These measurements in lavage fluid provide a method of monitoring the mucosal cellular events in response to therapy.

The contribution of histamine to the action of bradykinin in the human nasal airway

Bradykinin, 10 to 1000 micrograms given by aerosol into the nasal cavity of normal, healthy volunteers, produced a dose-related increase of nasal airway resistance. Bradykinin also reduced the minimal nasal cross-sectional area (Amin), increased albumin release into nasal lavage fluid and increased the symptoms of nasal inflammation. Pretreatment with cetirizine (10 mg orally) reduced the fall in Amin induced by bradykinin, 300 micrograms, but not by bradykinin, 100 micrograms. Pre-treatment of the subjects with the H1 histamine receptor antgonist cetirizine (10 mg, orally) or terfenadine (60 mg, orally) 3 h before bradykinin administration caused significant reduction of the bradykinin-induced increase in nasal airway resistance in the upper range of bradykinin doses (300-1000 micrograms) but not in the lower range (10-100 micrograms). Cetirizine reduced the albumin release into the nasal airway and the symptoms induced by bradykinin, 1000 micrograms. Following nasal challenge with bradykinin 300 micrograms or 1000 micrograms, no increase could be detected in the histamine content of nasal lavage fluid. Isolated human nasal cells released histamine in response to bradykinin, 33 and 100 microM, anti-IgE and calcium ionophore, A23187. We conclude that the actions of bradykinin in the human nasal airway are, in part, accounted for by the release of histamine.

Attenuation of human nasal airway responses to bradykinin and histamine by inhibitors of nitric oxide synthase

1. The effects of inhibitors of nitric oxide synthase and local anaesthetics were studied on changes in human nasal airway patency and albumin extravasation in response to bradykinin and histamine, in vivo. 2. Compared with the action of the vasoconstrictor, ephedrine, 2.5 mumol, NG-nitro-L-arginine methyl ester (L-NAME), 1 mumol alone, did not change the resting value of the minimal cross-sectional area (A min) of the human nasal airway. L-NAME, 0.1 to 10 mumol, produced a dose-related inhibition of the reduction in A min caused by bradykinin, 300 micrograms. NG-monomethyl-L-arginine (L-NMMA), 1 mumol, similarly reduced the effect of bradykinin, 300 micrograms, on A min, but NG-nitro-D-arginine methyl ester (D-NAME), had no effect. L-NAME, 0.1 to 10 mumol, or L-NMMA, 10 mumol, failed to inhibit the effect of histamine, 300 micrograms on A min. 3. The inhibition by L-NAME, 1 mumol of the action of bradykinin, 300 micrograms on A min was maximal between 15 and 30 min after pretreatment with L-NAME. 4. L-NAME, 1 and 10 mumol, inhibited the extravasation of albumin into the nasal cavity induced by bradykinin, 300 micrograms, and also by histamine, 300 micrograms. D-NAME, 1 and 10 mumol had no effect on the extravasation of albumin in response to bradykinin or histamine. 5. L-Arginine, 30 mumol, reversed the effect of L-NAME, 1 mumol, on the bradykinin- and histamine-induced albumin extravasation into the nasal airway. 6. Local anaesthesia of the nasal airway with lignocaine, 10 mg, or benzocaine, 10 mg, failed to inhibit the reduction in A min or the albumin extravasation induced by either bradykinin, 300 micrograms, and histamine, 300 micrograms. 7. We conclude that the extravasation of plasma albumin caused by bradykinin and by histamine involves the generation of nitric oxide. The nasal blockage induced by bradykinin involves nitric oxide generation but the nasal blockage induced by histamine does not.

Evidence that enhanced nasal reactivity to bradykinin in patients with symptomatic allergy is mediated by neural reflexes

OBJECTIVE

The aim of this study was to determine whether allergic inflammation induces nasal hyperreactivity to bradykinin by enhancing neuronal responsiveness.

METHODS

We compared the response to localized, unilateral nasal challenge with bradykinin in patients with perennial allergic rhinitis and nonallergic subjects, and in patients with seasonal allergic rhinitis challenged in and out of season. Weights of secretions from each nostril were recorded, and levels of albumin and lactoferrin in secretions recovered from each nostril were assayed. Contralateral administration of atropine (0.32 mg) was used to evaluate the role of cholinergic reflexes in nasal hyperresponsiveness to bradykinin.

RESULTS

In patients with symptomatic allergy, bradykinin induced greater symptom scores than in asymptomatic atopic or nonallergic control subjects. Moreover, bradykinin caused sneezing in a majority of patients with symptomatic allergy but in none of the asymptomatic atopic or nonallergic control subjects. Only patients with symptomatic allergy showed dose-dependent bilateral increases in secretion weights and levels of the serous glandular marker, lactoferrin. In contrast, bradykinin induced similar increases in ipsilateral, but not contralateral, levels of albumin in all patient populations. Atropine inhibited contralateral secretion and lactoferrin production (p < 0.05) in patients with symptomatic allergy.

CONCLUSION

The induction of sneezing and of atropine-inhibitable contralateral glandular secretion demonstrates that allergic inflammation causes nasal hyperreactivity to bradykinin, at least in part, by enhancing neuronal responsiveness.

Pathology of rhinitis and bronchial asthma

Studies of the pathology of rhinitis and asthma have identified similarities and differences between these two clinical conditions. With regard to symptoms, both the nose and the lower airways respond to neural stimulation by irritant substances, but a major difference is that engorgement of the capacitance vessels is the main cause of nasal obstruction in rhinitis, while muscle constriction is the major determinant of lower airway narrowing. There are also similarities and differences with respect to the role of inflammatory cells. In both conditions there is evidence of allergen-induced mast cell activation, with production of an array of mediators (some mast cell-derived and others originating from a variety of other cell types). Eosinophilia is also characteristic of both diseases--it is prominent even in mild forms of asthma, but is low in pollen-sensitive rhinitics outside of the season. T-cell activation and production of cytokines plays an important role in the development and maintenance of allergic disease, but the level of T-cell activation may differ between asthma and rhinitis. Further research into differences in cellular activity and response to treatment between these two diseases may help define factors which will determine whether atopic disease is expressed in the upper, lower, or both parts of the respiratory tract.

Peptidase inhibitors potentiate lysylbradykinin-induced bronchoconstriction in the rat

To determine whether lysylbradykinin (LBK, kallidin) causes bronchoconstriction in animals and if peptidase inhibitors modulate the response, we studied the effects of LBK administered by aerosol in rats and assessed whether pretreatment with aerosolized solutions of enalaprilat, an inhibitor of angiotensin converting enzyme (ACE), or phosphoramidon, an inhibitor of endopeptidase 24.11 (EP 24.11, neutral endopeptidase), altered the response. Accordingly, LBK-induced bronchoconstriction was measured in anesthetized, mechanically ventilated, specific pathogen-free, Sprague-Dawley rats by body plethysmography and followed by continuous determination of lung resistance (RL) and maximal expiratory flow (MEF). Incremental doses of aerosolized LBK were administered by nebulization to obtain a concentration that caused a 5-15% increase in RL, which was designated the BC10 dose. We found that pretreatment with aerosolized enalaprilat (1 mM) 3 min prior to a BC10 dose of LBK significantly increased RL as compared to the BC10 dose alone (129 +/- 4.1% vs. 105 +/- 2.4%, P < 0.002, n = 4) and significantly decreased MEF (83 +/- 1.5% vs. 97 +/- 1.4%, P < 0.008, n = 4). Following pretreatment with aerosolized phosphoramidon (1 mM), significant increases in RL (113 +/- 1.4% vs. 106 +/- 1.6%, P < 0.019, n = 7) and decreases in MEF (92 +/- 0.9% vs. 95 +/- 0.9%, P < 0.035, n = 7) were observed (paired Student's t-test). The above findings demonstrate the effects of LBK on airway caliber for the first time in an animal model, and suggest that ACE and EP 24.11 contribute to degradation of the peptide in the airway.

Inhibition of the response to nasal provocation with bradykinin by HOE-140: efficacy and duration of action

The present studies were undertaken as a first step to evaluate the potential usefulness of the bradykinin antagonist HOE-140 in delineating the role of kinins in the pathogenesis of chronic rhinitis. Intranasal single-dose administration of HOE-140, at doses up to 500 micrograms, was safe and well tolerated. Bradykinin-induced symptoms and increased vascular permeability could be inhibited, in a dose-dependent manner, by preadministration of HOE-140 5 min prior to kinin challenge. The results of dose-ranging experiments suggested that bradykinin and HOE-140 were approximately equipotent at bradykinin receptors. Preadministration of HOE-140 2 h before kinin challenge caused a significant but much weaker level of inhibition than that seen with 5-min preadministration. Comparison of data with those obtained during dose-ranging studies suggested that more than 90% of the administered HOE-140 was lost during this 2-h period. We conclude that topical HOE-140 is an effective inhibitor of the effects of bradykinin on the nasal mucosa but that the short duration of action of this drug may severely limit the utility of HOE-140 in delineating the role of kinins in the pathogenesis of chronic rhinitis.

Effects of ipratropium bromide on bradykinin nasal provocation in chronic allergic rhinitis

Bradykinin (BK) induces albumin exudation and glandular secretion in chronic allergic rhinitis subjects. Since bradykinin may stimulate nociceptive sensory nerves, neural reflex arcs could contribute to the secretion process. Six chronic allergic rhinitis subjects received 1000 nM bradykinin by unilateral nasal provocation using the method of Raphael et al. This dose induces optimal contralateral glandular secretion. Ipratropium bromide (80 micrograms) or saline were applied topically before the challenges. Total protein, albumin, glycoconjugate, and lysozyme were measured in lavage fluids. On the ipsilateral side, bradykinin induced significant total protein, glycoconjugate, and albumin secretion. None of these were affected by ipratropium. On the contralateral side, total protein and glycoconjugates were increased by bradykinin, while albumin and lysozyme were not significantly affected. Ipratropium bromide completely ablated total protein and glycoconjugate secretion on the contralateral side indicating that cholinergic reflexes mediated the glandular secretion. In chronic allergic rhinitis, bradykinin directly stimulated albumin secretion, but also stimulates nociceptive neuron--parasympathetic nerve reflexes to induce glandular secretion. The reflex loop was apparent on the contralateral side to the unilateral bradykinin challenge. This loop induced mucoglycoconjugate, but not serous cell, secretion in chronic allergic rhinitis subjects and can be inhibited by iptratropium bromide.

A study of the action of bradykinin and bradykinin analogues in the human nasal airway

1. The aim of this study was to investigate the action of bradykinin on resistance to airflow and on vascular permeability in the human nasal airway, and to explore the receptor mediating these effects. 2. Aerosol administration of bradykinin (10-1000 micrograms) caused a dose-related increase in nasal airway resistance (NAR) and an increase in albumin content of nasal lavage. 3. The bradykinin antagonists, [1-adamantane acetyl-D-Arg0, Hyp3, Thi5,8, D-Phe7]-bradykinin, 100 micrograms, and [D-Arg0, Hyp3, Thi5, D-Tic7, Oic8]-bradykinin, 100 micrograms, given 2 min before bradykinin, inhibited the increase in NAR and the increase of albumin content of nasal lavage caused by bradykinin. 4. The bradykinin antagonist, [D-Arg0, Hyp3, D-Phe7]-bradykinin (100 micrograms) did not affect the increase in NAR produced by bradykinin, or the albumin content of nasal lavage. Increasing the dose of the antagonist to 1000 micrograms did not change the increase in NAR induced by bradykinin. 5. The selective B1 kinin receptor agonist, [Des-Arg10]-kallidin (100 micrograms) did not affect NAR or the albumin content of nasal lavage. 6. The receptor mediating increased NAR and the release of albumin induced by bradykinin in the human nasal airway appears not to be a B1 kinin receptor. The data are not entirely consistent with the effects of bradykinin in the human nasal airway being mediated by a B2 kinin receptor.

Reduction by Hoe 140, the B2 kinin receptor antagonist, of antigen-induced nasal blockage

In subjects with allergic rhinitis to house-dust mite (HDM), antigen challenge produced a significant increase in nasal blockage but had no effect on nasal vascular permeability. The B2 kinin receptor antagonist, [D-Arg0,Hyp3,Thi5,D-Tic7,Oic8]-bradykinin (Hoe 140), 200 micrograms administered by intranasal aerosol 2 min prior to challenge with HDM, 500 u significantly reduced nasal blockage induced by the antigen challenge. The data are compatible with a role for B2 kinin receptors in the nasal response to challenge with antigen which is responsible for nasal blockage.

Acoustic rhinometry compared with posterior rhinomanometry in the measurement of histamine- and bradykinin-induced changes in nasal airway patency

1. Acoustic rhinometry is a relatively new method for objectively assessing nasal airway patency. In this paper we compare acoustic rhinometry with active posterior rhinomanometry. 2. Twenty normal healthy volunteers underwent nasal challenge with either histamine or bradykinin, 100 micrograms to 1000 micrograms, and responses were assessed by acoustic rhinometry. A further 20 subjects received identical nasal challenges and responses were assessed by active posterior rhinomanometry. 3. On a subsequent occasion, the subjects challenged previously with histamine, were given the selective H1-receptor antagonist, cetirizine, 10 mg orally, 3 h before repeat nasal challenge with histamine, 100-1000 micrograms. Again, responses were assessed by active posterior rhinomanometry and acoustic rhinometry. 4. The acoustic reflection measurements and the nasal airway resistance measurements showed comparable, significant dose-related changes in nasal patency to both histamine and bradykinin. Pretreatment with cetirizine blocked the histamine-induced change in nasal patency as measured by both methods. 5. We conclude that acoustic rhinometry has a number of advantages over posterior rhinomanometry. It is quick to perform, requires minimal subject co-operation and gives a reliable objective, measurement of dose-related changes in nasal airway patency before and after pharmacological treatment.

Sensory neuropeptide release by bradykinin: mechanisms and pathophysiological implications

Bradykinin (BK) and related kinins excite primary sensory neurons, thus leading to the activation of sensory impulses. More recently, both functional and neurochemical evidence have been accumulated that BK evokes release of neuropeptides, including calcitonin gene-related peptide and the tachykinins substance P and neurokinin A, from peripheral terminals of capsaicin-sensitive primary afferents. The present article will review the mechanisms and the pathophysiological implications of the ability of BK to release sensory neuropeptides at the peripheral level. An account of the clinical studies performed on this subject will be also given.

Comparative nasal effects of bradykinin and histamine: influence on nasal airways resistance and plasma protein exudation

BACKGROUND

Bradykinin may contribute to the pathogenesis of allergic rhinitis. Like histamine, nasal challenge with bradykinin induces rhinorrhoea, nasal blockage, and plasma protein leakage. Their comparative nasal potencies have not, however, been fully elucidated.

METHODS

Three double blind, randomised, placebo controlled and cross-over studies were undertaken to compare objectively the nasal effects of bradykinin, histamine, and vehicle.

RESULTS

Both bradykinin and histamine produced dose dependent increases in nasal airways resistance (NAR). There was no significant difference in the effects of bradykinin and histamine on NAR at any dose level. On a molar basis, however, bradykinin was 6.98 times more potent than histamine in inducing a 50% increase in NAR. Nasal challenge with bradykinin and histamine also induced significant rhinorrhoea compared with vehicle. The amount of rhinorrhoea induced by histamine was significantly greater than that induced by bradykinin at any dose level. Bradykinin and histamine induced dose dependent nasal pain and nasal itch respectively. When administered as single doses both bradykinin (1.9 mumol) and histamine (1.9 mumol) induced significant rhinorrhoea compared with the vehicle. The volume of rhinorrhoea secretions induced by histamine was 29% greater than that induced by bradykinin. In contrast, although NAR was increased significantly more by histamine than by the vehicle, the effect of bradykinin on NAR was significantly greater than histamine and vehicle in both magnitude and duration of effect. The incremental effect of bradykinin on lavage albumin levels was also significantly greater than both histamine and vehicle.

CONCLUSIONS

This study shows that the nasal vascular effects of histamine are less prominent than its actions on rhinorrhoea, and that the greater obstructive effect of bradykinin than histamine on NAR may contribute to the relative lack of efficacy of H1 antihistamines on nasal blockage in clinical disease.

The effect of BAY u 3405, a thromboxane receptor antagonist, on prostaglandin D2-induced nasal blockage

BACKGROUND

Nasal lavage and challenge studies in allergic rhinitis implicate prostaglandin (PG) D2 in the genesis of nasal blockage. PG D2 is known to act via at least two receptors, the thromboxane prostanoid receptor and the PG D2 prostanoid (DP) receptor; the lower airway effects are mediated chiefly by the TP receptor. The receptor involved in the genesis of PG D2-induced nasal blockage is unknown. BAY u 3405 is a potent selective competitive TP receptor antagonist, which inhibits the lower airway response to PG D2, and shifts the dose-response curve to the right by up to 16-fold.

METHODS

The efficacy of a single oral dose of 20 mg of BAY u 3405 was examined in comparison with PG D2 nasal insufflation in a randomized, double-blind, placebo-controlled crossover study, with objective measurement of nasal resistance by active posterior rhinomanometry.

RESULTS

BAY u 3405 afforded no protection against PG D2-induced nasal blockage.

CONCLUSIONS

This suggests that PG D2-induced nasal blockage may be mediated by the DP receptor rather than the TP receptor and that TP receptor antagonists are unlikely to be of benefit in the treatment of allergic rhinitis. In vivo investigation with specific potent DP receptor antagonists is awaited.

Bradykinin receptors: pharmacological properties and biological roles

Kinins contribute to the acute inflammatory response and are implicated in the pathophysiology of inflammatory disease. The development of therapeutically viable agents that counteract the effects of kinins is, therefore, potentially very rewarding. Since kinin actions are generally mediated via an interaction with cell-surface receptors, one approach is the development of site-specific receptor antagonists. The emphasis in this review is to outline our current understanding of the properties of bradykinin receptors and the potential therapeutic applications for drugs acting at these sites. As a result of the recent introduction of potent bradykinin receptor antagonists and the cloning of bradykinin receptor genes, considerable advances in kinin research can now be confidently anticipated.

The influence of terfenadine and ipratropium bromide alone and in combination on bradykinin-induced nasal symptoms and plasma protein leakage

Nasal instillation of bradykinin elicits many of the characteristic features of rhinitis. To assess the relevance of histamine release from metachromatic cells and the activation of cholinergic pathways, we investigated the effects of terfenadine, a histamine H1-receptor antagonist, and ipratroprium bromide, a selective antimuscarinic agent, on bradykinin induced rhinorrhoea, nasal airways resistance (NAR), nasal pain and plasma protein leakage. Oral terfenadine (120 mg) or matched placebo and nasal ipratropium bromide (80 micrograms) or matched placebo were administered at 4 hr and 30 min respectively prior to bradykinin nasal challenge in two randomized, double-blind and cross-over studies on eight non-rhinitic subjects. Thus subjects received either double-placebo, oral terfenadine and nasal placebo, oral placebo and nasal ipratopium bromide or oral terfenadine and nasal ipratropium bromide, as pretreatment. Bradykinin challenge induced mean maximal increases of 57%, 59%, 77% and 72% in NAR on the placebo, terfenadine, ipratropium bromide and terfenadine plus ipratropium bromide pretreatment days respectively. These increments were not significantly different. Similarly rhinorrhoea and nasal pain induced by bradykinin nasal challenge were not significantly different on the four challenge days. Bradykinin nasal challenge caused a mean maximal increase in albumin levels in recovered nasal lavages of 11.5, 13.0, 12.2 and 12.3 times of baseline levels on the placebo, terfenadine, ipratropium bromide and terfenadine plus ipratroprium bromide pretreatment days respectively. Similarly total protein levels achieved a mean maximal increase of 8.0, 8.2, 7.9 and 8.8 times of baseline levels on these challenge days. The increments in both albumin and total protein did not significantly differ on the 4 challenge days.(ABSTRACT TRUNCATED AT 250 WORDS)