Periodic feeding of SCN-lesioned pregnant rats entrains the fetal biological clock.
Destruction of the maternal suprachiasmatic nuclei (SCN) early in gestation disrupts maternal communication of time-of-day information to the rat fetus. In the present study, we demonstrated that periodic feeding (food cue) to SCN-lesioned pregnant rats entrains the fetal biological clock. The phase of the drinking behavior rhythm was examined in pups reared in constant darkness, beginning at weaning. In several control (uncued) litters, pup phases at weaning were scattered. In other control litters where within-litter coordination of phase was observed, the average litter phase was unpredictable. In contrast, drinking rhythms of pups whose dams had received food cue during gestation were synchronized within- and between-litters, suggesting that prenatal food cue entrained the fetuses. The effect of food cue occurs prenatally, as similar results were obtained when offspring of SCN-lesioned, cued dams were fostered to lesioned, uncued dams on the day of birth. The present results, along with data from this and other laboratories, suggest that redundant mechanisms communicate time-of-day information to the fetus.
Weaver
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DR
Laboratory of Developmental Chronobiology, Massachusetts General Hospital, Boston 02114.
Reppert
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SM
D000818:Animals; D002940:Circadian Rhythm; D005314:Embryonic and Fetal Development; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D051381:Rats; D013493:Suprachiasmatic Nucleus / Q000196:embryology / Q000502:physiology*