Effects of change of mothers and lighting conditions on the development of the circadian adrenocortical rhythm in blinded rat pups.
Free-running blood corticosterone rhythms were examined between the 4th and 9th postnatal week in blinded rat pups optically enucleated on day 1. The pups were born of mother rats having a free-running rhythm under constant illumination conditions and then were put under two separate illumination conditions (light - dark cycle and dark - light cycle) under the care of foster mothers already synchronized to each respective condition. Despite being born of the same mother rat, when the pups were raised by a mother with a different rhythm from that of the natural mother, they showed a different phase from that of the pups raised by the natural mother. Furthermore, each possessed different phase angles, depending on the rhythm of their respective foster mothers. On the other hand, although the rhythm of the natural mothers differed, when the rhythms of the nursing mothers were the same after birth, the blinded pups showed similar phase angles during the observation periods. These data suggested that the blinded pups were not affected by the rhythm of the natural mothers but rather showed a phase angle in accordance with the rhythm of the nursing mother.
D000818:Animals; D001766:Blindness / Q000097:blood; D002940:Circadian Rhythm; D003345:Corticosterone / Q000097:blood*; D005260:Female; D008027:Light; D009035:Mothers; D051381:Rats; D011919:Rats, Inbred Strains
D003345:Corticosterone