thromboxane-a2 and Sneezing

The aim of this study was to investigate the involvement of chemical mediators in a nasal congestion model in Brown Norway (BN) rats. For the above purpose, we studied the effects of pranlukast and zafirlukast (cysteinyl leukotriene (cys-LT) receptor antagonists), seratrodast and ramatroban (thromboxane A(2) (TXA(2)) receptor antagonists) on nasal congestion and sneezing induced by toluene 2, 4-diisocyanate (TDI). All of these drugs suppressed the increase of enhanced pause (Penh), the index of nasal congestion, in both early and late phase responses; however, pranlukast, zafirlukast and seratrodast failed to suppress immediate sneezing caused by TDI challenge. These results indicate that cys-LTs and TXA(2) are responsible for the development of both early and late phase nasal congestion. Moreover, these chemical mediators contribute very little to immediate sneezing in a BN rat model of allergic rhinitis.

Topics: Animals; Benzoquinones; Carbazoles; Chromones; Dose-Response Relationship, Drug; Heptanoic Acids; Indoles; Leukotrienes; Male; Membrane Proteins; Phenylcarbamates; Rats; Rats, Inbred BN; Receptors, Leukotriene; Receptors, Thromboxane A2, Prostaglandin H2; Rhinitis; Sneezing; Sulfonamides; Thromboxane A2; Tosyl Compounds

The purpose of this study was to investigate the involvement of chemical mediators other than histamine in nasal allergic signs using histamine H(1) receptor-deficient mice. In passively sensitized mice, antigen instillation into the nasal cavity induced significant increases in sneezing and nasal rubbing in wild-type mice, but no such increases were observed in histamine H(1) receptor-deficient mice. In actively sensitized mice, both sneezing and nasal rubbing were also significantly increased in a dose-dependent manner in both wild-type and histamine H(1) receptor-deficient mice. Histamine H(1) receptor antagonists such as cetirizine and epinastine significantly inhibited antigen-induced nasal allergic signs in wild-type mice, although the effects were incomplete. In addition, the thromboxane A(2) receptor antagonist ramatroban also inhibited these responses in wild-type mice. However, the leukotriene receptor antagonist zafirlukast showed no effects in wild-type mice. These results suggested that in the acute allergic model (passive sensitization), only histamine H(1) receptors are related to nasal signs induced by antigen, whereas in the chronic allergic model (active sensitization), both histamine H(1) receptors and thromboxane A(2) receptors were involved in the responses.

Topics: Animals; Anti-Allergic Agents; Antigens; Behavior, Animal; Carbazoles; Cetirizine; Dose-Response Relationship, Drug; Female; Histamine H1 Antagonists; Immunization; Immunoglobulin E; Indicators and Reagents; Indoles; Leukotriene Antagonists; Mice; Mice, Knockout; Ovalbumin; Passive Cutaneous Anaphylaxis; Phenylcarbamates; Receptors, Histamine H1; Rhinitis, Allergic, Seasonal; Sneezing; Sulfonamides; Thromboxane A2; Tosyl Compounds

We investigated the effects of the thromboxane (TX) A2 antagonist seratrodast, the peptide leukotriene (p-LT) antagonist pranlukast, the antihistaminic drug terfenadine and the glucocorticoid dexamethasone on antigen-induced sneezing, biphasic nasal blockage and nasal hyperresponsiveness to histamine using a guinea pig model of allergic rhinitis.. Male Hartley guinea pigs were used.. Intranasally sensitized guinea pigs were challenged once every week for 13 weeks by inhalation of Japanese cedar pollen as the antigen. Dexamethasone and other agents were administered orally 3 and 1 h, respectively, before the 4th, 6th and 13th challenge.. Sneezing frequency and the change in specific airway resistance (sRaw) were measured at these challenges. Two days after the 13th challenge, nasal responsiveness to histamine was evaluated by measuring sRaw after intranasal instillation of increasing doses of histamine. Moreover, the levels of TXB2, p-LTs and histamine were estimated in nasal cavity lavage fluid (NCLF) collected at the 13th challenge.. Only terfenadine (10 mg/kg) significantly inhibited sneezing at any challenge time. Seratrodast (3 and 10 mg/ kg), pranlukast (30 mg/kg) and dexamethasone (10 mg/kg), but not terfenadine, suppressed both the early and late phase elevation of sRaw (biphasic nasal blockage), although the degree of inhibition on the early phase response varied with the challenge time. In contrast, the development of nasal hyperresponsiveness to histamine was inhibited by only dexamethasone. Furthermore, biphasic increases in TXB2, p-LTs and histamine in NCLF were observed after the challenge in sensitized animals.. These results suggest that TXA2 and p-LTs, but not histamine, play important roles in both the early and the late phase nasal blockage in this model of allergic rhinitis.

Topics: Animals; Anti-Allergic Agents; Anti-Asthmatic Agents; Anti-Inflammatory Agents; Benzoquinones; Chromones; Dexamethasone; Guinea Pigs; Heptanoic Acids; Histamine; Histamine Release; Leukotrienes; Male; Nasal Cavity; Nasal Obstruction; Rhinitis, Allergic, Seasonal; Sneezing; Terfenadine; Therapeutic Irrigation; Thromboxane A2