Temperature as a Universal Resetting Cue for Mammalian Circadian Oscillators

Abstract

Time and Temperature Daily cycles in environmental temperature are an important cue for many organisms to synchronize their endogenous circadian clock. However, mammals do not respond to this cue. Studying mouse tissue, Buhr et al. (p. 379 ; see the Perspective by Edery ) find that this resistance to temperature is a feature specific to the suprachiasmatic nucleus (SCN), a region of the mammalian brain that functions as the body's master clock. In contrast, the clocks in peripheral tissues (for example, lung, liver) are fully capable of resetting in response to temperature changes and do so by a mechanism involving the heat shock pathway. The SCN drives daily rhythms in body temperature, and SCN-driven changes in temperature may synchronize the body's peripheral clocks. Without its intrinsic resistance to temperature, the SCN could be subject to disruptive feedback effects.