… -type hamsters exhibit a differential response to photoperiod change. Reproductively active
… may exhibit a shorter critical photoperiod than Charles River ie the opposite direction to that …

… :LVG from Charles River Quebec in the second). In both cases we left the hamsters in LL for
15 … in the previous experiments gave no signs of being active at any time of the manipulation. …

… Twenty male hamsters (LAK:LVG, from Charles River Quebec, 63 days old at the start of the
… became fully active. In both Experiment 1 and 2, a minority of hamsters were less active and …

… and circadian phase resetting to light in the Syrian hamster. This … Male Syrian hamsters
(Charles River, Montreal, Canada) … Although the hamsters were active during the SD, previous …

… the circadian clock … active period, can induce phase shifts in the circadian clock, and support
the hypothesis that feed-back signals during both the rest and active phases of the circadian …

… adult golden hamsters, 80--100 g, were obtained from Charles River Lakeview. … , hamsters
active on days of the cycle associated with less estrogen had larger shifts than animals active …

… hamster (Mesocricetus auratus; Charles River Breeding Labs) that exhibited an abnormally
shortT in constant dark (DD). Whereas the normal TDD for golden hamsters … ; activity onsets …

… 48 male golden hamsters (LVG Lak) were obtained from Charles River Lakev~ew (Newfield,
NJ) or were bred m our colony from ammals obtained from Charles River Prior to …

… (LAK/LVG strain, Charles River Laboratories, Wilmington, MA) to create a Wright’s–Charles
River hybrid heterozygote with an intermediate (22 h) circadian phenotype and thus control …

… circadian activity cycle is reduced from 24 to 20 h (3). The original defect occurred in a single
individual male supplied by Charles River … to the onset of the active period in the two groups…

… Spontaneous activity after sleep deprivation thus likely reflects an advanced onset of the
active phase of the circadian cycle, in addition to any residual arousal from the deprivation …

… ) females obtained from Charles River Laboratories, Quebec. … and circadian organization of
adult hamsters whose locomotor … to perform low levels of activity following the manipulation (…

… assumption has been incorrect; circadian rhythms of hamsters, mice and rats maintained in
… hamster's rest phase and maximum delays when applied at the end of the hamster's active …

… All hamsters (LAK:LVG, male, 60 days old upon arrival in our laboratory) were obtained from
Charles River (Montreal). Once in our laboratory, they were placed in LD 14:10 for 12 days, …

… background (tau SS , Charles River; tau ++ , Wright’s) of the hamster colonies used for this
part … are strongly seasonal breeders and remain reproductively active under long day lengths (…

… responses to light in hamsters are attenuated if simultaneous … were males obtained from
Charles River, Quebec (CRL, Lak:… to light was attenuated in the active animals. It is unlikely that …

… strain hamster (LAK/LVG), obtained from Charles River … Mutant animals born in London
were all of the Charles River … circadian hours (CTs 12-23), slightly longer than the active …

… were similar to those of the Charles River facility, and conditions in … Splitting of the circadian
rhythm of activity in hamsters: … Dark pulses affect the circadian rhythm of activity in hamsters …

… active in hamsters at doses equal to, or lower than, those reported for the mouse or rat. …
(Mesocricetus auratus) were purchased at one month of age from Charles River Laboratories (…

… feeding rhythm of rats or mice, the feeding pattern of hamsters shows a weak diurnal variation…
when young hamsters are normally active. So far, pharmacological approaches to improve …