APPW2025

Oranizers :Masaaki Ikeda (Department of Physiology, Faculty of Medicine, Saitama Medical University) and Teruya Tamaru (Department of Physiology, Toho University School of Medicin)

Organisms live in different time zones according to their diurnal adaptation to the environment. The biological clock, which is the basis of diurnal adaptation, consists of the central clock SCN in the brain and peripheral clocks throughout the body, and regulates various biological functions to occur at optimal times. In the resting period, the parasympathetic nervous system becomes dominant, and sleep, digestion and absorption, metabolism, repair, anti-oxidation, cell differentiation and division, etc. become active. In the early phase of active period, the SCN is commanded by the clock-synchronized signals of the light-responsive SCN to become sympathetically dominant, and cortisol secretion, blood flow and body temperature rise, thought, immune response, etc. become active. During the transition phase from late resting to early active period, immune responses, allergic symptoms due to inflammation, etc., and ischemic diseases associated with cardiovascular stress become more pronounced. Rapid environmental changes in recent years have caused health problems and diseases due to inadequate diurnal adaptation.In this symposium, we will discuss the latest findings on diurnal environmental adaptation phenomena based on the biological clock, which is responsible for switching between the resting and active periods, by approaching from physiological, anatomical, pharmacological, and nutritional aspects.