Inbred @entity19 have been routinely used in studies of genetic effects that determine behavioral variation due to circadian rhythm. In addition to activity patterns (Act), we aimed to characterize variations in the circadian rhythm of deep-body temperature (T(db)) and heart rate (HR) in a specific genetic model of differential cardiorespiratory control. Radiotelemeters were implanted in @entity28244 ( @entity28244 ; n = 11) and C57BL/6J (B6; n = 11) inbred strains. Reciprocal first-generation offspring, B6C3F1/J (B6F1; n = 8) and C3B6F1 (C3F1; n = 3) @entity19 , were included to initiate an evaluation of heritable phenotypes. @entity19 were housed individually in a facility maintained at 23-24 degrees C, and the light-dark cycle was set at 12-h intervals. In each animal, repeated measurements were obtained at 30-min intervals, and the circadian patterns of Act, T(db), and HR were assessed by novel statistical methods that detailed the periodic function for each strain. During the dark phase, B6 @entity19 demonstrated two distinct peaks in Act and T(db) relative to a single early peak for @entity28244 @entity19 . In contrast to the parental strains, B6F1 and C3F1 @entity19 demonstrated intermediate second peaks in Act and T(db). With respect to HR, the @entity28244 strain demonstrated a significantly (P < 0.01) greater daily average compared with B6 @entity19 . The circadian rhythm in HR differed significantly from the Act and T(db) patterns in B6 @entity19 (but not in @entity28244 @entity19 ); that is, the periodicity in HR for B6 @entity19 preceded the rise and fall in Act and T(db) during both peaks. The B6 phenotype was also observed in F1 @entity19 . In conclusion, these data suggest that the circadian regulation of Act, T(db), and HR vary significantly among @entity28244 , B6, and F1 @entity19 . Furthermore, phenotypic differences between @entity28244 and B6 strains can be used to explore the genetic basis for differential circadian regulation of body temperature and HR.

Circadian rhythm variation in activity, body temperature, and heart rate between XXXX and C57BL/6J inbred strains.

@entity19 :: ('10090', 'Species') :: ['mice', 'Mice'] @entity28244 :: ('12266(Tax:10090)', 'Gene') :: ['C3', 'C3H/HeJ']
@entity28244 :: (12266(Tax:10090),Gene) :: ['C3H/HeJ']
