Open Access

The circadian clock in mammals

  • Mauro Zordan and
  • Charalambos P. Kyriacou
The Journal of Headache and PainOfficial Journal of the Italian Society for the Study of Headaches1:103

The Erratum to this article has been published in The Journal of Headache and Pain 2005 6:242


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.

Key words Molecular chronobiologyCircadianMammalsGenesCluster headachePain