Anti-asthmatic activity of newly synthesized calcium antagonists: 2-n-butyl-1 (N-methyl-n-[2-(N',N'-dimethylamino)ethyl]amino) -5,6-methylenedioxy-indene and -indane

The anti-asthmatic activity of the newly synthesized methylenedioxyindene (MDI) derivatives, 2-n-butyl-1 (N-methyl-N-[2-(N', N' -dimethylamino)ethyl]amino)-5, 6-methylenedioxy-indene (MDI-C) and -indane (MDI-D), were investigated in vitro and in vivo in guinea pigs. The in vitro pharmacological activity of both derivatives was compared to that of 8-(diethylamino)octyl-3,4, 5-trimethyoxybezoate hydrochloride. All three agents caused a concentration-dependent inhibition of the antigen-induced contraction of sensitized guinea pig tracheal smooth muscle. In histamine and leukotriene D4-induced contractions of guinea pig tracheal smooth muscle, each agent showed clear antagonistic actions. Additionally, all three agents demonstrated potent calcium antagonistic actions via inhibition of guinea pig tracheal smooth muscle contractions caused by CaCl2 in a high potassium and Ca-free medium and by compound 48/80 in a solution of ethylene glycol bis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid in a contained Ca-free medium. MDI-C and MDI-D inhibited the antigen-induced release of histamine and slow reacting substance of anaphylaxis from sensitized guinea pig lung tissue. Lastly, both MDI is clearly inhibited asthmatic respiratory disorders without affecting blood pressure in guinea pigs.     

Effect of cinnarizine on IgE antibody-mediated experimental allergic reactions in guinea pigs

The anti-allergic activity and mechanism of cinnarizine was investigated in guinea pigs. Nifedipine, a calcium antagonist, and tranilast, a potent, orally active anti-allergic agent, were used as comparative drugs. Cinnarizine protected against fatal systemic anaphylactic shock in guinea pigs passively sensitized with IgE antibody. Cinnarizine reduced many of the features of severe respiratory disorders. Nifedipine and tranilast showed similar effects. Cinnarizine and nifedipine inhibited the contractile response to antigen of sensitized tracheal smooth muscle when the challenge was carried out at low antigen concentrations. Tranilast showed a tendency to inhibit the antigen-induced contraction of tracheal smooth muscle. Cinnarizine and nifedipine inhibited Ca-induced contraction in potassium-depolarized tracheal smooth muscle, tranilast had no effect. Cinnarizine showed antagonistic action to the contraction by histamine or leukotriene D4 (LTD4) of tracheal muscle. Nifedipine showed similar antagonistic action, although its potency is lower than cinnarizine. Tranilast showed slight antagonistic action to LTD4. Antigen-induced release of histamine and slow reacting substance of anaphylaxis (SRS-A) from sensitized lung tissues was inhibited by nifedipine and tranilast but not by cinnarizine. The release of histamine and SRS-A from lung tissues by calcium ionophore A23187 was inhibited by nifedipine and tranilast but not by cinnarizine. These results suggest that the anti-allergic action of cinnarizine is mainly due to the antagonistic action to allergic mediators and not by interfering with the release of mediators. Cinnarizine's mechanism seems to be related to its antagonistic action to Ca in smooth muscle, but not to the transport of Ca in releasing the anaphylactic chemical mediators in mast cells and other target cells.     

Quercetin inhibits anaphylactic contraction of guinea pig ileum smooth muscle

Certain flavonoids inhibit antigen-induced release of histamine from mast cells and basophils and also inhibit contraction of guinea pig ileum induced by histamine, acetylcholine, and PGE2. We examined the effect of one flavonoid, quercetin, on anaphylactic smooth muscle contraction of ileum from guinea pigs sensitized to egg albumin. Quercetin inhibited both the phasic and tonic components of anaphylactic contraction in a concentration-dependent fashion (IC50 approximately 10 microM). Whether this is primarily an effect on mast cell mediator release or inhibition of mediator effects on smooth muscle has not been established.     

Inhibition of antigen-induced contraction of guinea pig isolated tracheal muscle with 2-n-butyl-3-dimethylamino-5,6-methylenedioxy indene (MDI-A), indane (MDI-B) and 8-(diethylamino)octyl-3,4,5-trimethoxy benzoate hydrochloride (TMB-8)

The effects of three intracellular calcium antagonists on antigen-induced contraction of sensitized guinea pig tracheal muscle were investigated. The agents employed were: 2-n-butyl-3-dimethylamino-5,6-methylenedioxy indene hydrochloride (MDI-A), 2-n-butyl-3-dimethylamino-5,6-methylenedioxy indane hydrochloride (MDI-B) and 8-(diethylamino)octyl-3,4,5-trimethoxy benzoate hydrochloride (TMB-8). Each of these agents caused a concentration-dependent inhibition of the antigen-induced contraction of sensitized tracheal smooth muscle. Moreover, in histamine and leukotriene D4 (LTD4) incited contractions of guinea pig tracheal muscle, they showed antagonistic action. The induced tracheal muscle contraction, achieved through the addition of compound 48/80 to a solution of ethylene glycol bis (beta-aminoethylether)-N,N,N1, N1-tetraacetic acid (EGTA) in a contained Ca-free medium, was completely inhibited by individual pretreatment with MDI-A, MDI-B and TMB-8. In the case of tracheal muscle contraction induced by CaCl2 in a high potassium, Ca-free medium, only TMB-8 inhibited contraction. Lastly, none of these three intracellular calcium antagonists affected the antigen-induced release of histamine and slow reacting substance of anaphylaxis (SRS-A). These results suggest that MDI-A and MDI-B inhibit the antigen-induced contraction of sensitized guinea pig tracheal muscle by interfering with the contractile responses caused by histamine and LTD4.     

Bronchoprotective effects of atrial natriuretic peptide against propranolol-induced bronchoconstriction after allergic reaction in guinea pigs

OBJECTIVE: To study the effects of intravenous atrial natriuretic peptide (ANP) on antigen-induced bronchoconstriction, propranolol-induced bronchoconstriction (PIB) after antigen challenge, and histamine-induced bronchoconstriction in guinea pigs. METHODS: Allergic bronchoconstriction was evoked by inhalation of ovalbumin (OA) and PIB was caused when 10 mg/mL of propranolol was inhaled 20 min after OA challenge in passively sensitized and artificially ventilated guinea pigs. 25, 50, 100 and 200 microg/mL of histamine were inhaled for 20 s at 5-min intervals in non-sensitized guinea pigs. RESULTS: Pretreatment with ANP in doses of 0.1 and 1.0 nmol/kg injected intravenously 15 min after antigen challenge reduced PIB in a dose-dependent manner, and 5 min before antigen challenge significantly attenuated PIB but not antigen-induced bronchoconstriction. Intravenous ANP significantly reduced bronchial responses to increasing concentrations of inhaled histamine in a dose-dependent manner. CONCLUSION: These results suggest that ANP possesses protective effects against propranolol-induced and histamine-induced bronchoconstriction, albeit by a non-specific mechanism in guinea pig in vivo.     

The influence of a new corticosteroid,budesonide, on anaphylactic bronchoconstriction and SRS-A release in the guinea pig

Groups of guinea pigs sensitized with ovaibumin were treated with budesonide and beclomethasone dipropionate, respectively, in an intraperitoneal dose of 50 mg/kg. 20 h later, the anaphylactic release of histamine and slow reacting substance of anaphylaxis (SRS-A) from chopped lung tissue was studied. Whereas the corticosteroids studied had no effect on the tissue content of histamine or on the amount of antigen-induced release of this autacoid, budesonide and beclomethasone dipropionate to a great extent inhibited the release of SRS-A. The anti-anaphylactic effect of budesonide and beclomethasone was also shown in sensitized guinea pigs pretreated with mepyramine, 2.5 mg/kg intraperitoneally, and challenged with nebulized ovalbumin. We suggest that the partial protection given by the corticosteroids budesonide and beclomethasone dipropionate is due to the inhibition of SRS-A release.Subsidiary of AB Astra, Sweden.     

The role of calcium antagonists in bronchial reactivity

Calcium (Ca) ions play an important pathophysiologic role in allergic reactions. Thus, mediator release from mast cells, synthesis of some newly formed chemical mediators, airway smooth muscle contraction, and nerve-impulse conduction are all dependent on the availability and flux of Ca ions. It is likely, therefore, that Ca antagonists would modify allergic bronchoconstriction. In vitro, Ca antagonists have been demonstrated to inhibit mediator release (histamine, slow-reacting substance of anaphylaxis, and platelet-activating factor) from mast cells, passively sensitized human lung fragments, and leukocytes. Ca antagonists have also been found to inhibit synthesis of leukotrienes in rat lungs and cyclooxygenase products in sheep, possibly by inactivating phospholipase A2 and/or 5-lipoxygenase. In addition, nifedipine, verapamil, and gallopamil have demonstrated inhibition of airway smooth muscle contractions to histamine, carbachol, and antigen in various species. In vivo effects of Ca antagonists are variable, depending on the species, experimental design, the stimulus or the agonist, and the Ca antagonist used. Animal studies have demonstrated the inhibition of histamine, methacholine, citric acid, and prostaglandin F2 alpha-induced bronchoconstriction in guinea pigs and dogs by intravenous nifedipine. In contrast, verapamil inhibited antigen-induced bronchoconstriction in allergic sheep without any effect on histamine- and carbachol-induced responses. Ca antagonists (nifedipine and verapamil) have been of limited value in human subjects and generally have no significant bronchodilating activity. Both nifedipine and verapamil prevent the exercise-induced asthma and partly attenuate the histamine and methacholine-induced bronchoconstriction. Oral nifedipine is generally more effective than oral verapamil against acute antigen-induced bronchoconstriction; however, this efficacy may be limited by systemic side effects. Inhaled Ca antagonists may be more effective and free of systemic side effects, as demonstrated by greater efficacy of inhaled verapamil. A new Ca antagonist, gallopamil (a methoxy derivative of verapamil), is being investigated as an aerosol, and preliminary studies in animals and humans have found it fourfold to seventeenfold more potent than verapamil. In sheep, gallopamil has been found to attenuate histamine, carbachol, and platelet-activating factor-induced bronchoconstriction, as well as to inhibit early and late-phase allergic airway responses. Studies in human subjects have also demonstrated the inhibition of antigen-induced bronchoconstriction by inhaled gallopamil, with efficacy comparable or better than cromolyn sodium.(ABSTRACT TRUNCATED AT 400 WORDS)     

Histamine-releasing activity of lymphocyte supernatants of guinea pig spleen cell cultures

We demonstrated the production of a histamine releasing factor (HRF) by 24-h cultures of guinea pig spleen cells which were stimulated or not with specific antigen (ovalbumin, OA) or mitogen (phytohemagglutinins or concanavalin A). HRF induced the release of histamine from homologous mesenteric mast cells in a dose-dependent fashion. The HRF-induced histamine release was not high compared to the release induced by calcium ionophore A23187, but higher than that induced by compound 48/80, polymyxin B and con canavalin A. The mast cells from sensitized guinea pigs released histamine when challenged with OA. We found that HRF-induced histamine release was additive to that induced by antigen, when both agents were added simultaneously to sensitized mast cells. The phenomenon was most significant when a suboptimal dose of antigen was used. Moreover, we did not observe any differences in the magnitude of HRF-induced histamine release between the mast cells from nonsensitized and sensitized guinea pigs. The time course of histamine release induced by HRF was significantly slower than that with specific antigen (10 min and 45 sec, respectively). Our results may suggest that HRF acts on mast cells through a different not immunological mechanism.     

Histamine-releasing properties of guinea pig cardiac mast cells

The immunization of guinea pigs with OA + Al(OH)3 induced substantial IgG1a and IgG1b antibody response and low, transient IgE response, as examined by PCA test. Cardiac mast cells obtained by enzymatic dispersion method from sensitized animals released histamine in vitro after the challenge with specific antigen (histamine release up to 21%). Cardiac mast cells obtained from nonsensitized guinea pigs were sensitive to the action of ionophore A23187 and polymyxin B only when the agents were used in high concentrations (histamine release up to 25.1% and 21. respectively) and were only slightly responsive to the challenge with Concanavalin A and compound 48/80.     

Effects of NZ-107 on bronchoconstriction in guinea pigs.

The effect of 4-bromo-5-(3-ethoxy-4-methoxybenzylamino)-3(2H)-pyridazinone (NZ-107) on bronchoconstriction in guinea pigs was studied (1). The antigen-induced bronchoconstriction was studied in guinea pigs which had been passively sensitized by intravenous injection of antiserum containing anti-benzylpenicilloyl bovine-gamma-globulin IgE antibody. The sensitized guinea pigs were divided into two groups; one group was pretreated with metyrapone (11 beta-hydroxylase inhibitor in glucocorticoid metabolism) and the other with saline. The antigen-induced bronchoconstriction in the metyrapone-treated animals was more severe than that in the saline-treated animals. The asthmatic respiratory changes, in terms of prolongation of the ratio between expiration and inspiration, was also dramatically increased. NZ-107 at doses of 25 and 50 mg/kg significantly inhibited antigen-induced bronchoconstriction in both the saline-and metyrapone-treated animals. NZ-107 showed a tendency to inhibit accelerated severe asthmatic respiration more strongly in metyrapone-treated animals than in those treated with saline. Salbutamol inhibited antigen-induced bronchoconstriction in saline-treated animals, but its efficacy decreased in metyrapone-treated animals. Unlike salbutamol, prednisolone and hydrocortisone showed the reverse effect, inhibiting bronchoconstriction in metyrapone-but not in saline-treated animals. Sodium cromoglycate inhibited antigen-induced bronchoconstriction in both saline- and metyrapone-treated animals (2). When a subthreshold dose of platelet-activating factor was injected into guinea pigs, airway responsiveness against histamine was clearly increased. NZ-107 at a dose of 0.2 mg/kg i.v. inhibited PAF-induced airway hyperreactivity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reduction of antigen-induced contraction of sensitized guinea-pig tracheal smooth muscle in vitro by calmodulin inhibitors

The effect of two calmodulin inhibitors, 1-[bis(p-chlorophenyl)methyl]-3-[2,4-dichloro-beta-(2,4-dichlorobenzylox y) phenethyl]imidazolinium chloride (R 24571) and chlorpromazine (CPZ) on antigen-induced contraction of guinea-pig tracheal smooth muscle was studied. Ketotifen, an anti-allergic compound, was used as a comparative drug. Contraction of sensitized guinea-pig trachea induced by antigen challenge was reduced by all three agents. The two calmodulin inhibitors effected relaxation of contraction of guinea-pig trachea induced by histamine and leukotriene D4 (LTD4). Ketotifen relaxed histamine-induced contraction, but hardly affected LTD4-induced tone. Contrary to chemical mediator induced tone, all examined agents had no effect on resting tone. These three agents shifted histamine- and LTD4-induced concentration-contraction curves to the right. They produced a downward displacement of the maximum, without a parallel shift in histamine- and LTD4-induced concentration-contraction curves. The two calmodulin inhibitors did not affect the antigen-induced release of histamine and SRS-A from sensitized guinea-pig lung tissue. Ketotifen slightly inhibited the release of histamine. These results suggest that R 24571 and CPZ, calmodulin inhibitors, reduced an antigen-induced contraction of sensitized guinea-pig trachea in vitro mainly by affecting the contractility of tracheal smooth muscle by chemical mediators but not by interfering with the release of mediators.     

Effects of aerosol antigen challenge in vivo on responsiveness of guinea pig tracheal and parenchymal strips in vitro to contractile agonists

Guinea pigs sensitized to produce IgG-like antibodies were challenged with aerosol antigen in vivo. The following day responses in vitro to histamine and carbachol of tracheal and lung parenchymal strips (LPS) from challenged animals and unchallenged controls were compared. Responses of LPS to both histamine and carbachol were increased in challenged animals but tracheal strips from challenged guinea pigs did not display increased sensitivity to histamine or carbachol compared with controls. Moreover, the sensitivity of tracheal strips to carbachol decreased in challenged animals. The increased sensitivity of LPS from challenged animals may be due to the release of chemical mediators and down regulation of postsynaptic muscarinic receptors may account for the decreased sensitivity of tracheal strips.     

CI-922--a novel, potent antiallergic compound--I. Inhibition of mediator release in vitro

CI-922 (3,7-dimethoxy-4-phenyl-N-1H-tetrazol-5-yl-4H-furo[3,2-b]-indole- 2-carboxamide, L-arginine salt) is a novel antiallergy compound which inhibits the release of the inflammatory mediators histamine and leukotriene (LT) from stimulated cells. CI-922 showed potent, effective inhibition of antigen-induced mediator release from human basophils and isolated guinea pig lung. The drug inhibited ragweed or housedust-induced histamine release from basophils of allergic human donors (IC50 = 8.6 microM). The antiallergy agents proxicromil (IC50 = 80 microM) and cromolyn (100 microM) were less potent than CI-922 or inactive, respectively. In fragmented lung from actively sensitized guinea pigs, CI-922 (IC50 = 1.5 microM), blocked the antigen-induced production of LT and was a more potent inhibitor of histamine release (IC50 = 13.4 microM) than proxicromil (IC50 = 72.9 microM), or cromolyn (inactive at 1 mM). CI-922 (IC50 = 0.9 microM) completely inhibited repeated contractions of guinea pig lung strips that were induced by low antigen concentration in the presence of antihistamine (H1). Nordihydroguaiaretic acid (NDGA) (IC50 = 2.8 microM), proxicromil (IC50 = 6.2 microM) and the LT antagonist FPL-55712 (IC50 = 3.3 microM) also were fully effective, but cromolyn (300 microM) was inactive. In other experiments, CI-922 (IC50 = 7.0 microM) inhibited a strong, nonrepeatable lung contraction induced with high antigen concentration (histamine responses blocked), and was six times more potent than FPL-55712. Other investigations in isolated tissue preparations showed CI-922 to be a weak inhibitor of LT or histamine-induced effects with no anticholinergic activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

BRL 22321, a compound that has mast cell stabilizing activity similar to that of disodium cromoglycate and in addition has smooth muscle relaxing activity

BRL 22321 is 4,9-dihydro-6,7-dimethyl-4,9-dioxo-1H-naphtho[2,3-d]-v-triazole sodium salt. It combines some of the chemical structural features of disodium cromoglycate (DSCG) and theophylline. It has mast cell stabilizing activity similar to that DSCG and in addition it has some smooth muscle relaxant activity. BRL 22321 was more potent than DSCG as an inhibitor of rat passive cutaneous and peritoneal anaphylaxis (PCA and PPA) and histamine release by antigen from passively sensitized rat peritoneal cellsin vitro. In the rat PCA test it was active when given orally and a large intravenous dose of DSCG reduced the potency of subsequent intravenous doses of either DSCG or BRL 22321, suggesting that the compounds were active by a common pathway. The compounds had similar potencies as inhibitors of the release, by antigen, of histamine and slow reacting substance of anaphylaxis (SRS-A) from passively sensitized human lung fragments. BRL 22321 was more potent than DSCG and theophylline as an inhibitor of a cyclic adenosine and a cyclic guanosine monophosphate phosphodiesterase. BRL 22321 inhibited histamine release in systems in which DSCG was inactive, for example it inhibited histamine release by antigen from chopped lung taken from hyperimmune guinea pigs and by anti-IgE from human leucocytes; in these tests it was more potent than theophylline. BRL 22321 had smooth muscle relaxant activity not shown by DSCG. It relaxed histamine elevated tone in guinea pig lung strip and tracheal spiral preparations at doses at which theophylline produced a dose dependent response. It was difficult to compare potencies since there was a difference in the nature of the responses to the drugs. DSCG had little activity over the same dose range or at higher doses. BRL 22321 also reduced increased airways resistance in the anaesthetized guinea pig produced by 5-hydroxytryptamine (5-HT) or histamine but at somewhat higher doses than those at which theophylline was active. BRL 22321 was not an antagonist of acetylcholine, histamine, 5-HT or SRS-A on the isolated guinea pig ileum.     

In vitro studies on the mechanism of action of a new antiallergic,Ro 21-7634

The effects of Ro 21-7634 and disodium cromoglycate (cromoglycate) on the in vitro release of mediators of anaphylaxis from rat peritoneal cells and guinea pig lung tissue were compared. Ro 21-7634 was 25 fold more potent than cromoglycate as an inhibitor of antigen-induced histamine release from passively sensitized (IgE) rat peritoneal cells. Ro 21-7634 was also the more potent inhibitor of both compound 48/80- and concanavalin A-induced histamine release from rat peritoneal cells. The two drugs shared the common properties of producing the same maximal level of inhibition in each of the above releasing systems and exhibiting a time and concentration dependent loss of inhibitory activity when added to the cells prior to the releasing agent. Neither drug inhibited ionophore A23187- or ionophore X537A-induced histamine release from these cells. Ro 21-7634 inhibited antigen-induced (IgG₁) histamine and SRS-A release from actively sensitized guinea pig lung fragments, whereas cromoglycate did not. The results indicate that Ro 21-7634 and cromoglycate act through a common mechanism to inhibit allergic mediator release and that Ro 21-7634 is the more potent inhibitor.     

Effects of leukotriene B4 receptor antagonist, LY293111Na, on antigen-induced bronchial hyperresponsiveness and leukocyte infiltration in sensitized guinea pigs

OBJECTIVE AND DESIGN: LY29311 Na, 2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy] propoxy] -phenoxy]-benzoic acid sodium salt, is a novel leukotriene B4 (LTB4) receptor antagonist. Its effects on guinea pig models of asthma were compared with those of dexamethasone. METHODS: Effects of LY293111Na were tested in antigen (ovalbumin, OA)-induced bronchial hyperresponsiveness (BHR) and leukocyte accumulation in actively sensitized guinea pigs. Its effects on antigen-induced acute bronchoconstriction in passively sensitized guinea pigs were also studied. RESULTS: LY293111 Na (10 to 30 mg/kg p.o., 1 h before and 6 h after OA challenge) inhibited BHR to acetylcholine. LY293111 Na (3 mg/kg p. o.) significantly inhibited accumulation of neutrophils in bronchoalveolar lavage (BAL) fluid 24 h after antigen challenge but it did not inhibit accumulation of eosinophils and macrophages at any doses used. In contrast, dexamethasone (30 mg/kg p.o., 4 h before OA challenge) not only inhibited BHR but also reduced the infiltration of all three types of leukocytes. A significant increase of LTB4 levels in BAL fluid was noted at 3 and 15 min after the antigen challenge. LY293111Na did not inhibit antigen-induced acute bronchoconstriction in passively sensitized guinea pigs. CONCLUSION: These results indicate that LTB4 may participate in antigen-induced BHR but not in eosinophil infiltration and acute bronchoconstriction in guinea pigs.     

Inhibition of acute lung anaphylaxis by aerosolized azelastine in guinea pigs sensitized by three different procedures

The influence of aerosolized azelastine on acute lung anaphylaxis in actively sensitized guinea pigs (experimental asthma model) was studied. Azelastine administered as an aerosol produced significant inhibition of acute lung anaphylactic responses, ie, the reduction in dynamic lung compliance and an increase in pulmonary airway resistance. These data showed that regardless of the method of sensitization and time of administration (immediately or 15 minutes before antigen challenge), aerosolized azelastine affords significant protection against acute lung anaphylaxis. The inhibition of acute lung anaphylaxis by aerosolized azelastine in the guinea pig asthma model may be due to (1) inhibition of the synthesis/release of chemical mediators, eg, histamine and leukotrienes, etc and/or (2) antagonism of the pharmacologic mediators at the receptor site in respiratory smooth muscles.     

Antigen-induced release of histamine from rat tissues in vitro: dissociation in development of serosal mast cell, lung tissue, and tracheal tissue response capacity

We examined the temporal development and the fading in Sprague Dawley rats, actively sensitized to ovalbumin (OA), of the capacity of serosal mast cells, chopped lung tissue, and occasionally chopped tracheal tissue, to respond at antigen challenge in vitro with histamine release. Response capacity of both serosal mast cells and lung tissue developed within 2-3 weeks after injection of 1 microgram OA or more together with 100 mg of alum. Maximum response capacity was observed in cells and tissue from animals injected with 10 micrograms OA, part of the response capacity then remained until 3 months after immunization. Development of serosal mast cell reactivity was occasionally dissociated from that of lung tissue. When low amounts of alum (1 or 10 mg) were employed as adjuvant, lung tissue reactivity could be induced in the virtual absence of serosal mast cell response capacity. Silica gel was less efficient than alum as an adjuvant for induction of a primary response, but 'secondary' tissue responses could be induced when silica gel was used as an adjuvant. Pretreatment of the animals with cyclophosphamide before the booster injection enhanced and prolonged the response capacity of lung tissue. Animals injected with OA together with Freund's complete adjuvant did not provide responding serosal mast cells; response capacity of lung tissue varied with immunization dose of antigen. Antigen-induced histamine release from chopped tracheal tissue did not correlate to response capacity of lung tissue. Thus, the development in the rat of response capacity with respect to antigen-induced histamine release dissociates from serosal mast cells, lung tissue, and tracheal tissue.     

The influence of cyclic nucleotides on histamine release from lungs and on the histamine-induced contraction of guinea pig ileum

Conclusion In conclusion, exogenous cAMP and cGMP exert certain opposite actions on antibody-induced histamine release from guinea pig lungs as well as on histamine or antigen-induced contraction of guinea pig ileum smooth muscle.     

Role of Respiratory Epithelium in the Development of Hyperreactivity of Bronchial Smooth Muscles

In guinea pigs sensitized with ovalbumin the respiratory epithelium lost its ability to modulate the responses of airway smooth muscles to histaminergic stimuli. Incubation of bronchial segments with IL-5 potenntiated the contractile responses of bronchial smooth muscles to histamine in both intact and sensitized animals. Incubation of bronchial segments with IL-5 receptors moderated contractile activity of segments from sensitized pigs, but not in the segments from intact controls. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 9, pp. 250–252, September, 2005