calcimycin and amlexanox

Antiallergic effects of 6-(1-pyrrolidinyl)-N-(1H-tetrazol-5-yl)-2-pyrazinecarboxamide (HSR-6071), a newly synthesized agent, were investigated. The 48-hr homologous passive cutaneous anaphylaxis (PCA) in rats was inhibited in a dose-dependent manner by i.v. and p.o. administration of the agent (ED50 = 0.0096 mg/kg and 0.18 mg/kg, respectively). The IgE-mediated histamine release from rat peritoneal exudate cells was inhibited by HSR-6071, with an IC50 of 4.6 x 10(-10) M. Regarding the non-immunological histamine release, HSR-6071 inhibited compound 48/80-induced, but not A23187-induced and spontaneous histamine release. On the other hand, an increase in vascular permeability induced by histamine, serotonin and bradykinin was unaffected by HSR-6071 in doses sufficient to inhibit PCA. In addition, the contractile responses of isolated guinea pig ileum to histamine, acetylcholine and serotonin were also unaffected by the agent even in a high concentration of 10(-4) M. These results indicate that HSR-6071 possesses a potent antiallergic activity and that the inhibition of PCA by HSR-6071 may be due to the suppression of chemical mediators release from mast cells.

Topics: Aminopyridines; Animals; Antigens; Ascaris; Azoles; Calcimycin; Cromolyn Sodium; Dinitrophenols; Guinea Pigs; Histamine Release; Ileum; Immunoglobulin E; Ketotifen; Male; Muscle Contraction; Muscle, Smooth; p-Methoxy-N-methylphenethylamine; Passive Cutaneous Anaphylaxis; Pyrrolidines; Rats; SRS-A; Tetrazoles

Amoxanox has potent antiallergic activity because it inhibits the release of chemical mediators such as histamine and leukotrienes. We studied the in vitro effect of amoxanox on arachidonic acid metabolism, including the lipoxygenase and cyclooxygenase pathways. Amoxanox inhibited calcium ionophore A23187-induced formation of 5-HETE, LTB4, SRS-A (LTC4, LTD4 and LTE4), and 12-HETE in rat peritoneal resident monocytes. These results indicate that amoxanox inhibits 5- and 12-lipoxygenases. The compound, however, did not affect the formation of TXB2 or 6-keto-PGF1 alpha in guinea pig lung fragments and PGE2 or PGF2 alpha in bovine seminal vesicles, suggesting that it did not inhibit cyclooxygenase. These results show that the antiallergic action of amoxanox is associated, at least in part, with the reduction of leukotrienes due to the inhibition of lipoxygenases.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; 5,8,11,14-Eicosatetraynoic Acid; Aminopyridines; Animals; Asthma; Calcimycin; Cattle; Guinea Pigs; Histamine H1 Antagonists; Hydroxyeicosatetraenoic Acids; Hypersensitivity; In Vitro Techniques; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Male; Monocytes; Prostaglandins; Rats; Rats, Inbred Strains; SRS-A; Thromboxane B2