Interaction between Two Circadian Clocks in the Rabbit and Their Main Input
It was previously shown [review in 1] for the rabbit that photosensitivity of the visual system fluctuates according to a block-shaped circadian rhythm. The time courses of this rhythm after exposure to 24 hrs light-dark alternations or to constant environmental circumstances strongly suggest that this rhythm is governed by a central circadian mechanism with the properties of a double-oscillator. These 2 oscillators may correspond with the Morning- and Evening type oscillators which have been described for hamsters and other rodents [2,3]. This raised the following questions: — does the rabbit show corresponding circadian changes in food intake? If so, is there any indication that this rhythm also is controlled by a double-oscillator? And, in case of the latter, how do these separate oscillators respond to entrainment by light-dark regimens or to constant photic circumstances?
- 1.A.C. Bobbert and J. Brandenburg: “Characteristics of the Interaction Between the Central Circadian Mechanism and the Retina in Rabbits”. In Vertebrate Circadian Systems. Ed. by J. Aschoff, S. Daan and G. Groos. Springer Verlag Berlin-Heidelberg-New York, 52–61 (1982)Google Scholar