Takeshi Nabe1, Nobuaki Mizutani1, Seiichi Osaki1, Shingo Sugahara1, Hiroshi Takenaka2 and Shigekatsu Kohno1,*
1Department of Pharmacology, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi, Yamashina, Kyoto 607-8414, Japan
2Department of Otorhinolaryngology, Osaka Medical College, 2-7 Daigaku-cho, Takatsuki, Osaka 569-8686, Japan
*Corresponding author. FAX: +81-75-595-4764, E-mail: kohno@mb.kyoto-phu.ac.jp
Abstract: We have developed an allergic rhinitis model in guinea pigs using Japanese cedar pollen as antigen. In the present study, we examined whether provocation by pollen induces similar magnitudes of rhinitis symptoms in passively and actively sensitized guinea pigs. One group of animals was actively sensitized by intranasal application of pollen extract, and another was passively sensitized by intraperitoneal injection with anti-pollen serum. Actively and passively sensitized groups were then challenged by repeated and a single pollen inhalation, respectively. In both groups, sneeze was induced immediately after the challenge. The actively sensitized animals developed not only early but also late nasal blockage, whereas the passively sensitized animals showed only early nasal blockage. In both groups, an H1 antagonist, mepyramine, inhibited the occurrence of sneezing but did not inhibit nasal blockage. Nasal hyperresponsiveness to intranasal instillation of leukotriene D4 was obvious only in the actively sensitized animals. We thus conclude that although early nasal blockage is induced by a single antigen-antibody reaction, repetitive anaphylactic reaction is required for occurrence of late nasal blockage and hyperresponsiveness to stimuli. Furthermore, histamine plays a central role in induction of sneezing but not in nasal blockage, irrespective of whether animals are actively or passively sensitized.
Keywords: Allergic rhinitis, Cedar pollen, Histamine, IgE, Nasal blockage
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