목적: Allergic rhinitis (AR) is characterized by typical symptoms such as rhinorrhea, itching, sneezing and nasal blockage. The severity of nasal congestion follows circardian rhythm, being worst at night and in the early morning. Sneezing and rhinorrhea secondary to AR are greater in intensity during morning. The mechanism involving in circardian rhythm of AR is not clearly understood yet. We speculate that these symptoms are under control of the circardian clock. The present study is to investigate the expression and distribution pattern of clock gene in human and rat nasal mucosa, and further evaluate the expression levels of clock gene in mild, and moderate/severe persistent allergic nasal mucosa. 방법:Clock genes (per1, per2, clock, BMAL1) were evaluated in normal and allergic nasal mucosa using RT-PCR, real-time PCR, immunohistochemistry, and western blot. Cultured epithelium derived from normal turbinates was used to evaluate the effect of glucocorticoids on the clock genes. The expression levels of clock genes were evaluated in time series analysis using real time PCR. 결과:Cloke genes mRNA and proteins are expressed in normal and allergic nasal mucosa. Their expression levels in mild and moderate/severe persistent allergic nasal mucosa were decreased compared with normal nasal mucosa. The expression levels of clock genes in cultured epithelial cells were increased by glucocorticoids administration. The rhythmical curve of these genes levels were noted in rat nasal mucosa in time-dependent manner. 결론:The present results showed that clock genes (per1, per2, clock, BMAL1) were present in human and rat nasal mucosa. Deregulated expression of these genes may participate in the pathogenesis of allergic nasal mucosa. Furthermore, these genes may possibly contribute to the development of the nasal cycles.