The effect of temporal adaptation to different temperatures and osmolarities on heat response of TRPV4 in cultured cells.

Abstract

Transient receptor potential vanilloid 4 (TRPV4) channel is a polymodal receptor activated by moderate heat and hypoosmolarity. TRPV4 expressed in the skin area contributes to several skin functions as a barrier to maintain internal body physiology and a transporter of external stimuli. The skin condition such as skin temperature and osmolarity varies with internal and external changes, and may influence the activity of TRPV4 contributing to skin physiology, thermal sensation, and thermoregulation. However, the combination effect of skin conditions such as temperature and osmolarity on the activity of TRPV4 has not been examined. In the current study, we investigated the effect of temporal adaptation (5-10\u202fmin) to different temperature (25-35\u202f°C) and osmolarity (250-350 mOsm) conditions on the heat response (until 40\u202f°C) of human TRPV4 in cultured cells using Ca2+ imaging. The temperature to activate TRPV4 increased with elevation of the adaptation temperature, and decreased with the adaptation to hypoosmolarity in the range of 25-35\u202f°C. In addition, the heat response was inhibited with the adaptation to hyperosmolarity in the range of 25-35\u202f°C. Thus, we demonstrated that the activation temperature of TRPV4 varied with the temporal sensory adaptation to different temperature and osmolarity conditions. These findings may contribute to gaining better understanding of the variation in several TRPV4-mediated skin functions.