15-hydroxy-11-alpha-9-alpha-(epoxymethano)prosta-5-13-dienoic-acid and Nasal-Obstruction

Bayer has been interested in the observations that metabolites of arachidonic acid are involved in allergy and inflammation. Ramatroban was thus developed as a therapeutic agent for allergic and inflammatory diseases. Ramatroban showed an antagonistic action on the thromboxane A2 (TXA2) receptor in in vitro experiments using platelets or arteries. It inhibited the permeability of capillary and also the infiltration of eosinophils in nasal mucosa. Ramatroban had an inhibitory effect on the nasal resistance stimulated by either U-46619 or antigen challenge in in vivo experiments. The concentration of nasal TXA2 was increased when the antigen was challenged to allergic patients. Clinical trials demonstrated that ramatroban decreased sneezing, rhinorrhea, and rhinostenosis in patients enrolled in the study. No serious adverse reaction of ramatroban was observed in patients throughout the trials. The treatment with ramatroban is safe and improves nasal symptoms.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Airway Resistance; Animals; Capillary Permeability; Carbazoles; Clinical Trials as Topic; Humans; Nasal Cavity; Nasal Mucosa; Nasal Obstruction; Receptors, Thromboxane; Rhinitis, Allergic, Perennial; Sulfonamides

We examined the role of prostanoid DP receptor in nasal blockage in an experimental allergic rhinitis model in guinea pigs. Local inhalation of prostaglandin D(2) (PGD(2)) to the nasal cavity resulted in an increase in intranasal pressure in guinea pigs actively sensitized by repeated antigen exposure but not in non-sensitized guinea pigs. Nasal hyperresponsiveness was observed when the guinea pigs were exposed to histamine and U-46619 (11alpha, 9alpha-epoxymethano-PGH(2); a thromboxane (TX) A(2) mimetic) after repeated antigen exposure. S-5751 ((Z)-7-[(1R,2R,3S,5S)-2-(5-hydroxybenzo[b]thiophen-3-ylcarbonylamino)-10-norpinan-3-yl]hept-5-enoic acid), a prostanoid DP receptor antagonist, inhibited not only PGD(2)-induced nasal blockage but also nasal hyperresponsiveness to histamine and U-46619 in sensitized guinea pigs. Combined exposure of the nasal cavity of guinea pigs to an aerosol of PGD(2) with histamine or U-46619 at sub-threshold concentrations synergistically caused a marked increase in intranasal pressure. These responses were significantly suppressed by S-5751. These results suggest that PGD(2) plays a critical role in the increase in intranasal pressure via prostanoid DP receptor, probably through synergistically enhancing the nasal response with other chemical mediators released from mast cells and other inflammatory cells activated by allergens.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Administration, Intranasal; Allergens; Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Guinea Pigs; Histamine; Male; Nasal Mucosa; Nasal Obstruction; Nose; Ovalbumin; Pressure; Prostaglandin D2; Receptors, Immunologic; Receptors, Prostaglandin; Rhinitis, Allergic, Perennial; Thiophenes; Time Factors

Although thromboxane (TX)A2 is involved in allergic rhinitis, the mechanisms inducing nasal blockage have not been elucidated. We evaluated the roles of nasal mucosal vascular changes following intranasal instillation of the TXA2 analog U-46619 or leukotriene (LT)D4 to induce nasal blockage in a guinea pig model of allergic rhinitis. Both U-46619- and LTD4-induced nasal blockages in sensitized animals were swiftly and completely suppressed by a vasoconstrictor, naphazoline. The nitric oxide synthase inhibitor N(omega)-nitro-l-arginine methyl ester relieved LTD4-induced nasal blockage, but not U-46619-induced nasal blockage. Although both agonists produced vasodilatation of nasal mucosa in vivo, LTD4 caused vasodilatation while U-46619 caused vasoconstriction in vitro. Both LTD4- and U-46619-induced nasal blockages in vivo should depend on vasodilatation of nasal mucosa. LTD4-induced nasal blockage is induced by direct vasodilatation via nitric oxide. In contrast, U-46619-induced nasal blockage may be associated with contraction of a certain vein that should exist at the exit of capacitance vessels, leading to congestion of the nasal mucosa.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Airway Resistance; Animals; Blood Vessels; Disease Models, Animal; Drug Synergism; Guinea Pigs; Leukotriene D4; Male; Models, Biological; Naphazoline; Nasal Mucosa; Nasal Obstruction; NG-Nitroarginine Methyl Ester; Nitric Oxide; Phenylephrine; Pollen; Rhinitis, Allergic, Seasonal; Thromboxane A2

To estimate the involvement of thromboxane (Tx) A2 in the onset of nasal blockage, we examined the effect of the selective TxA2 receptor antagonist, S-1452, as well as an H1-antihistamine, diphenhydramine, on the antigen-induced increase in intranasal pressure, as an index of nasal blockage, in anesthetized guinea pigs actively sensitized by inhalation of aerosolized ovalbumin (OA). Oral administration of S-1452 or intravenous administration of diphenhydramine significantly but incompletely reduced the increase in intranasal pressure following exposure of the nasal cavity of guinea pigs to aerosolized OA. In combination, the two agents were more effective than either alone, but there was no significant difference between them. The TxB2 level was significantly elevated in nasal lavage fluid 15 and 30 min after antigen challenge. Exposure of the nasal cavity of guinea pigs to aerosolized U-46619, a TxA2 mimetic, also resulted in a marked increase in intranasal pressure, and this could be almost completely suppressed by S-1452. These findings suggest that TxA2 contributes to antigen-induced nasal blockage in guinea pigs.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Administration, Inhalation; Animals; Antigens; Bridged Bicyclo Compounds; Diphenhydramine; Fatty Acids, Monounsaturated; Guinea Pigs; Histamine; Male; Nasal Obstruction; Ovalbumin; Prostaglandin Endoperoxides, Synthetic; Thromboxane A2; Thromboxane B2