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The circadian clock in mammals

The Original Article was published on 01 December 2000


The basic physiological and anatomical basis for circadian rhythms in mammalian behaviour and physiology is introduced. The pathways involved in photic entrainment of the circadian clock are discussed in relation of new findings that identify the molecules that are involved in signalling between the environment and the clock. The molecular basis of endogenous cycles is described in the mouse, and compared to the mechanism that is present in the fly. Finally we speculate on the relationship between circadian physiology and pain.

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Correspondence to C. P. Kyriacou.

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Zordan, M.A., Kyriacou, C.P. The circadian clock in mammals. J Headache Pain 6, 424 (2005).

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Key words

  • Molecular chronobiology
  • Circadian
  • Mammals
  • Genes
  • Cluster headache
  • Pain