| Abstract: | Developmental studies of circadian function in mammals are generally difficult because of the close interaction between mother and young. The European rabbit presents an exception, providing developmental chronobiologists with an unusual opportunity to study the early development of circadian function. Doe rabbits only visit their newborn young once a day to nurse for a few minutes, and pups anticipate this regular event with heightened arousal and by uncovering of the nest. Both the mother's nursing visit and pups' anticipatory arousal represent well synchronized circadian rhythms. They also represent discrete, quantifiable events that can be readily manipulated by controlling does' access to the pups, by cross-fostering or by eliminating a nursing either before, during or after the development of visual function. The doe's long absence makes it possible to carry out surgical or other interventions without disrupting the normal pattern of maternal care, and the correspondence between pups' anticipatory arousal and the expression of c-Fos in hypothalamic nuclei demonstrates the suitability of this model for investigating the neural basis of early circadian function. |
