Effect of disease modifying antirheumatic drugs and nonsteroidal antiinflammatory drugs upon cellular and fibronectin responses in a pleurisy model.

Intrapleural injections of carrageenan into rats resulted in peak increases in intrapleural inflammatory cell counts (90% mononuclear cells) and fibronectin content at 3 days after the injections. Administration of disease modifying antirheumatic drugs (DMARD) prevented the increases in both fibronectin levels and intrapleural cell counts, whereas nonsteroidal antiinflammatory drugs, in general, potentiated the increases. Inhibition of fibronectin production by DMARD in carrageenan induced pleurisy in rats may be related to the antirheumatic activity of this class of drugs.

Differential effects of pharmacologic agents on the reverse passive Arthus reaction in guinea pigs.

Five different pharmacologic agents were examined for their effects upon edema, hemorrhage, and vascular infiltration by neutrophils in the reverse passive Arthus reaction (RPAR) in guinea pigs. Two agents, colchicine (3.0 mg/kg p.o.) and ibuprofen (100 mg/kg p.o.) significantly inhibited all three parameters of RPAR. Cobra venom factor (100 units/kg i.p.) inhibited edema and hemorrhage but it did not inhibit neutrophil infiltration. Aminophylline and sulfinpyrazone (100 mg/kg p.o.) inhibited only hemorrhage; they did not inhibit edema or neutrophil infiltration. The results from these studies with five chemically or biologically unrelated pharmacologic agents suggest that the RPAR in guinea pigs can be separated into its basic components (edema, hemorrhage, and neutrophilic infiltration) by selective inhibitors. Inhibition of edema and hemorrhage, or hemorrhage alone of the two-hour RPAR in guinea pigs is not dependent upon inhibition of neutrophilic infiltration.

Effects of FPL 55712, ETYA and aminophylline upon Ascaris-induced bronchoconstriction in cynomolgus monkeys.

Dose-related impairment of pulmonary functions was induced in artificially respired, anesthetized cynomolgus monkeys by inhalation of aerosolized Ascaris antigen (AA) in ascending doses. The effects of pharmacologic agents were assessed by increases in threshold Ascaris dose (TAD). TAD were defined as the doses of AA needed for 20% increase in pulmonary resistance and 15% decrease in compliance. Inhaled FPL 55712, an SRS-A antagonist (1.24 mg through-the-valve dose; TTVD), and 5,8,11,14-eicosatetraynoic acid (ETYA), an inhibitor of lipoxygenase and cyclooxygenase (1.0 mg TTVD) resulted in significant increases in the geometric means of TAD for changes in compliance (p less than 0.01). The effects of both agents upon resistance were of borderline significance. Orally administered aminophylline (30 mg/kg) had no significant effect upon mean TAD for resistance or compliance. The activities of FPL 55712 and ETYA suggest that spasmogenic leukotrienes are involved in the pulmonary allergic reactions in cynomolgus monkeys.

Novel orally active inhibitors of passive cutaneous anaphylaxis in rats: N-[2-(4-pyridinyl)-4-pyrimidinyl]ureas and dialkyl [[[2-(4-pyridinyl)-4-pyrimidinyl]amino]methylene]malonates.

4-Chloro-2-(4-pyridinyl)pyrimidines were treated with alkylamines to afford the corresponding N-substituted amino derivatives. 4-Amino-2-(4-pyridinyl)pyrimidines and their N-substituted analogues were converted to amides, carbamates, aminomethylenemalonates, and ureas. Many of these compounds were found to have potential antiallergic activity as indicated by the rat passive cutaneous anaphylaxis screen. The most compounds were found in the last two series.

Relaxant effects of amrinone upon pulmonary smooth muscle.

Amrinone, a cardiac positive inotropic agent, inhibited histamine-induced bronchoconstriction in a dose-related manner in dogs when administered intra-duodenally at doses ranging from 0.3 to 10 mg/kg. This bronchodilatory property of amrinone in vivo was confirmed in vitro: amrinone relaxed carbachol-induced contractions and it inhibited Ba2+- or histamine-induced contractions of guinea pig tracheas. When amrinone was examined for its inhibition of histamine contractions under modified Ca2+ availability, the EC25 and EC75 of amrinone were 76 and 8 times smaller, respectively, under conditions of intracellular rather than normal Ca2+ availability. The corresponding decreases for verapamil were 12,414 and 33 times. No meaningful changes in the potencies of amrinone or verapamil were seen when normal Ca2+ availability was changed to extracellular Ca2+ availability. These data suggest that verapamil, and partially amrinone, inhibit histamine-induced tracheal contractions by reducing the bioavailability of intracellular Ca2+.

Comparison of effects of investigational compounds upon allergic phenomena in rodents in vivo and in human basophils in vitro.

Investigational compounds active in anti-allergic/anti-asthmatic screens in rodents in vivo (IgE-mediated passive cutaneous anaphylaxis in rats, IgE-mediated anaphylactic bronchoconstriction in guinea pigs, and histamine-, or acetylcholine-induced bronchoconstriction in guinea pigs) were examined for their effects against IgE-mediated histamine release from human basophiles. Fifty-seven% (19/33) of investigational compounds active against passive cutaneous anaphylaxis in rats and 40% (12/30) of compounds active against anaphylactic bronchoconstriction in guinea pigs were active also against histamine release from human basophiles. Twenty-eight percent (8/29) and 38% (6/15) of compounds active agonist histamine- and acetylcholine-bronchoconstriction in guinea pigs, respectively, were active also against histamine release from human basophiles. The lack of consistent activity of investigational compounds in the in vivo IgE-mediated anaphylactic screens suggests that diverse inhibitory mechanisms are involved. Anaphylactic histamine release from human basophiles may serve as an adjunct in the determination of the activity profiles of new antiallergic agents. It is of limited value in the search for new bronchodilators.

Pharmacologic characterization of immune complex induced bronchoconstriction in guinea pigs.

Intravenous injections of soluble immune complexes to anesthetized guinea pigs resulted in bronchoconstriction that was inhibited by FPL 55712, indomethacin, oxarbazole, soybean trypsin inhibitor, and cobra venom factor. Immune complex induced bronchoconstriction was not inhibited by atropine, imidazole, mepyramine, ketotifen, methysergide, and the anti-anaphylactic compound DPP (Diethyl [2-(4-pyridyl)-4-pyrimidinyl]aminoethylene malonate). Immune complex induced bronchoconstriction in guinea pigs appears to involve activation of complement and formation of anaphylatoxins. In addition, products of cyclo-oxygenase metabolism of arachidonic acid and kinins may be involved.

The effects of antiasthmatic drugs against immune complex-induced bronchoconstriction in anesthetized dogs.

Bronchoconstriction was induced in nonsensitized dogs by intravenous injections of soluble immune complexes. Immune complex-induced bronchoconstriction was associated with a drop in blood pressure and a drop in the circulating complement levels. Different antiasthmatic agents were compared for their effects in dogs against bronchoconstriction induced by intravenous injections of immune complexes or histamone. Bronchodilators (isoproterenol, aminophylline, and bitolterol) inhibited both types of bronchoconstriction, whereas disodium cromoglycate, prednisone, and oxarbazole inhibited only bronchoconstriction induced by immune complexes. Thenyldiamine and atropine inhibited histamine- and carbachol-induced bronchoconstriction, respectively, but they were ineffective at the same doses against immune complex-induced bronchoconstriction.

Evaluation of the antiasthmatic potential of oxarbazole in guinea pigs.

Oxarbazole, 9-benzoyl-2,3,4,9,-tetrahydro-6-methoxy-1H-carbazole-3-carboxylic acid, inhibited bronchoconstriction induced by a crude SRS-A preparation or by bradykinin in dose-related manner in anesthetized guinea pigs. Oxarbazole was ineffective against bronchoconstriction induced by histamine, carbachol, serotonin, or PGF2alpha. Inhibition of bonchoconstriction induced by the crude SRS-A preparation by oxarbazole was unimpeded by the presence of beta-adrenergic- or cholinergic-blocking agents, but it could be overcome by increased doses of the SRS-A preparation.