Abstract
The understanding of the mammalian circadian system profoundly progressed in recent years. The recent molecular dissection of the biological clock has revealed that circadian oscillations are generated by interacting positive and negative transcription/translation feedback loops of a set of clock genes. This molecular core oscillator is present in most cells in the body, and thus it is believed that mammalian circadian system is composed of multiple oscillatory systems with a hierarchical architecture. The master clock in the hypothalamic suprachiasmatic nucleus (SCN) drives slave oscillators in peripheral tissues. In this circadian system, the central and peripheral autonomic nervous system has an important role in carrying the circadian signals from the SCN clock to the peripheral organs. In all airway tissues, we investigated the role of vagal nerve activity on the respiratory clock. We will discuss the circadian role of airway mucin and muscarinic acetylcholine receptors. Vagal signaling will be essential gears in conferring circadian time information to airway glands. [J Physiol Sci. 2008;58 Suppl:S13]
