Phase shifts and Per gene expression in mouse suprachiasmatic nucleus

Yan, Lili; Hochstetler, Kelly J.; Silver, Rae; Bult‐Ito, Abel

doi:10.1097/00001756-200307010-00012

Cited by 8 publications

(6 citation statements)

References 24 publications

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“…This is in agreement with previous studies suggesting a relationship between the light-induced mPer2 gene and the phase-delay response (Albrecht et al, 2001;Yan and Silver, 2002;Yan et al, 2003). It is unlikely that there are differences in mPer1 induction between the DARPP-32 KO and WT mice at time points not examined here, because the peak response occurs after 90 min of light exposure for both mPer1 and mPer2 (Takumi et al, 1998;Yan and Silver, 2002).…”

Section: Discussionsupporting

confidence: 93%

DARPP-32 Involvement in the Photic Pathway of the Circadian System

Yan¹,

Bobula²,

Svenningsson³

et al. 2006

J. Neurosci.

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The multifunctional regulator of protein kinases and phosphatases dopamine-and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32) is an important molecular target of the dopamine signaling pathway. In the present study, we investigated the possible involvement of DARPP-32 regulation in the circadian system using DARPP-32 knock-out (KO) mice. These mice showed normal entrainment to a 12 h light/dark cycle and free run in constant darkness with a period similar to that of wild-type controls. After light exposure, however, the behavioral phase-delay response and the expression of light-induced clock gene mPer2 were attenuated in the DARPP-32 KO mice. Attenuated phase delays were also seen in animals bearing a point mutation in DARPP-32 at the PKA (Thr34) but not at the casein kinase I (Ser130) phosphorylation site. We next examined DARPP-32 expression in the retina and intergeniculate leaflet (IGL), both of which convey light information to the suprachiasmatic nucleus (SCN), the locus of a master circadian clock, and in the SCN itself. DARPP-32 was expressed in the retina but not in the IGL or the SCN. The results indicate that DARPP-32 is involved in the retinal pathway transmitting photic information that resets the circadian clock.

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Section: Discussionsupporting

confidence: 93%

DARPP-32 Involvement in the Photic Pathway of the Circadian System

Yan¹,

Bobula²,

Svenningsson³

et al. 2006

J. Neurosci.

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“…In this study, the time course for entrainment by scheduled feeding was much longer than that reported for photic entrainment (34). However, the time course was similar to the gradual process by which mice entrain to daily schedules of voluntary or forced running (13,18).…”

Section: Discussionmentioning

confidence: 40%

“…Testing in cages with running wheels revealed significant differences between big and small nest builders in several circadian rhythm characteristics, including robustness of the locomotor activity rhythm and magnitude of light-induced phase shifts (2,4,34). These lines also show characteristic differences in expression of some clock gene mRNAs and proteins within the SCN (2,4,7,34).…”

Section: Animals Male Mice (Mus Domesticus)mentioning

confidence: 99%

“…Mouse chow (Purina Mills, Lab Diet Mouse Diet #5015, St. Louis, MO) was available ad libitum until the start of scheduled feeding, whereas access to water was unrestricted throughout the experiment. Wheel running data were collected in 5-min bins using the VitalView data-collection system (MiniMitter, Bend, OR) following standard protocols (2,34). Activity data were analyzed with the following software: Actiview (MiniMitter), ClockLab (Actimetrics, Evanston, IL), and MatLab (The MathWorks, Natick, MA).…”

Section: Animals Male Mice (Mus Domesticus)mentioning

confidence: 99%

“…Male mice (Mus domesticus) at least 50 days old at the start of experiments were taken from four lines bidirectionally selected for thermoregulatory nest building behavior, which resulted in two independently maintained replicate lines each of small and big nest builders [line 1 (small 1), line 2 (small 2), line 3 (big 1), and line 4 (big 2) (3, 6, 7)]. Testing in cages with running wheels revealed significant differences between big and small nest builders in several circadian rhythm characteristics, including robustness of the locomotor activity rhythm and magnitude of light-induced phase shifts (2,4,34). These lines also show characteristic differences in expression of some clock gene mRNAs and proteins within the SCN (2, 4, 7, 34).…”

mentioning

confidence: 99%

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Entrainment of the master circadian clock by scheduled feeding

Castillo

Hochstetler

Tavernier

et al. 2004

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

119

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The master circadian clock, located in the mammalian suprachiasmatic nuclei (SCN), generates and coordinates circadian rhythmicity, i.e., internal organization of physiological and behavioral rhythms that cycle with a near 24-h period. Light is the most powerful synchronizer of the SCN. Although other nonphotic cues also have the potential to influence the circadian clock, their effects can be masked by photic cues. The purpose of this study was to investigate the ability of scheduled feeding to entrain the SCN in the absence of photic cues in four lines of house mouse (Mus domesticus). Mice were initially housed in 12:12-h light/dark cycle with ad libitum access to food for 6 h during the light period followed by 4 -6 mo of constant dark under the same feeding schedule. Wheel running behavior suggested and circadian PER2 protein expression profiles in the SCN confirmed entrainment of the master circadian clock to the onset of food availability in 100% (49/49) of the line 2 mice in contrast to only 4% (1/24) in line 3 mice. Mice from line 1 and line 4 showed intermediate levels of entrainment, 57% (8/14) and 39% (7/18), respectively. The predictability of entrainment vs. nonentrainment in line 2 and line 3 and the novel entrainment process provide a powerful tool with which to further elucidate mechanisms involved in entrainment of the SCN by scheduled feeding. nonphotic entrainment; scheduled feeding; suprachiasmatic; PER2; wheel running activity THE SUPRACHIASMATIC NUCLEI (SCN) of the anterior hypothalamus are the master circadian (near 24 h) clock in mammals, entraining clocks located in other brain regions and peripheral organs (26,33). The clock mechanism consists of molecular feedback loops containing positive and negative elements, i.e., clock gene products, that cycle with a near 24-h period in the absence of external signals (26). Light, the strongest natural zeitgeber or timing cue, shifts the clock so that it can entrain to the external light/dark (LD) cycle (28). Scheduled food availability is one of several nonphotic periodic signals (24, 25) that have been shown to entrain behavioral rhythms (17,19,22). Although entrainment of the master circadian clock was inferred in these studies (17,19,22), it was not confirmed at the level of the SCN (12).When feeding is dissociated from the normal activity period by allowing animals to eat only during their inactive period, two behavioral activity components result. One component entrains to and is in anticipation of onset of food availability, i.e., food anticipatory activity (FAA), which is controlled by an SCN-independent food-entrainable clock. The other is the animal's normal nocturnal or light-entrainable activity (LEA) component, which is controlled by the SCN when food access is not limited and has been presumed to be controlled by the SCN when access to food is temporally limited (8). The likelihood of the free-running LEA component being entrained by scheduled daily feeding in constant dark (DD) is species dependent. Hamsters typically show behavior...

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Transcriptional Regulation of Circadian Clocks

Ripperger

Brown

2009

The Circadian Clock

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Phase shifts and Per gene expression in mouse suprachiasmatic nucleus

Cited by 8 publications

References 24 publications

DARPP-32 Involvement in the Photic Pathway of the Circadian System

DARPP-32 Involvement in the Photic Pathway of the Circadian System

Entrainment of the master circadian clock by scheduled feeding

Transcriptional Regulation of Circadian Clocks

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