EXPRESSION OF HISTAMINE-RECEPTORS IN NASAL EPITHELIAL-CELLS AND ENDOTHELIAL-CELLS - THE EFFECTS OF SEX-HORMONES

Background: Hyperreactivity of the nasal mucosa is a characteristic of nasal allergy During pregnancy, aggravation of nasal allergic symptom s is occasionally observed in subjects with nasal allergy. Methods: Us ing the reverse transcription-polymerase chain reaction and Southern b lot hybridization method, we investigated histamine H1 receptor mRNA ( H1R mRNA) expressions in specimens of nasal epithelial layer obtained by scraping, as well as cultured human nasal epithelial cells (HNECs) and human mucosal microvascular endothelial cells (HMMECs). We compare d the expressions on the specimens from patients with nasal allergy wi th those with nonallergic rhinitis or those from normal volunteers. In addition, we investigated die effects of female hormones on the H1R m RNA expressions in HNECs and HMMECs. Results: H1R mRNA was detected in scraped specimens of nasal epithelial layer, as well as in HNECs and HMMECs. The mRNA expressions in nasal mucosal scraped specimens of epi thelial layers and HNECs were more marked in patients with nasal aller gy than in the other two groups. In addition, the present study demons trates that the female hormones beta-estradiol and progesterone signif icantly increase the expressions of H1R mRNA on HNECs and HMMECs. Conc lusion: The increase of the expressions of H1R mRNA may explain, in pa rt, the nasal hyperreactivity to histamine observed in patients with n asal allergy It has also been suggested that sex hormones are related to the preponderance of females in the incidence of allergic rhinitis after puberty, and that they are related, at least partially, to the a ggravation of the nasal hyperreactivity symptoms during pregnancy thro ugh the enhanced expression of H1R mRNA on HNECs and HMMECs.