What is the Origin of Peripheral Clock Entrainment?

This concept emerged from chronobiology research that identified the existence of clock genes not only in the suprachiasmatic nucleus (SCN) but also in virtually every cell in the body. The term 'entrainment' specifically refers to the synchronization of a rhythm to an external cue, distinguishing it from the rhythm itself.

What is the Mechanism of Peripheral Clock Entrainment?

While the SCN provides the primary signal, peripheral clocks are highly sensitive to non-photic cues, known as Zeitgebers, with nutrient signaling being paramount. Timed feeding can acutely reset the liver clock, for instance, by activating nutrient-sensing pathways like the insulin-Akt pathway, which in turn regulates local clock gene expression. This entrainment ensures that the metabolic machinery of each organ is prepared for the incoming flux of nutrients or the fasting state, maximizing physiological throughput.

Peripheral Clock Entrainment

Meaning

Peripheral clock entrainment is the process by which the circadian rhythms of individual organs and tissues outside of the brain’s master clock are synchronized and aligned with the external 24-hour cycle. These peripheral clocks, found in the liver, pancreas, muscle, and adipose tissue, regulate local metabolic and hormonal functions. Effective entrainment, often achieved through timed feeding or exercise, is essential for maintaining metabolic harmony and preventing chronic metabolic disorders.