TY - JOUR
T1 - Endogenous rhythms in period1 mutant suprachiasmatic nuclei in vitro do not represent circadian behavior
AU - Pendergast, Julie S.
AU - Friday, Rio C.
AU - Yamazaki, Shin
PY - 2009/11/18
Y1 - 2009/11/18
N2 - The mammalian circadian pacemaker in the suprachiasmatic nuclei (SCN) controls daily rhythms of behavior and physiology. Lesions of the SCN cause arrhythmicity of locomotor activity, and transplants of fetal SCN tissue restore rhythmic behavior that is consistent with the periodicity of the donor's genotype, suggesting that the SCN determines the period of the circadian behavioral rhythm. While several studies have demonstrated that the circadian characteristics of in vitro SCN rhythms represent circadian behavior, others have shown that the periods of explanted SCN are not always congruent with locomotor activity. We find that the aberrant rhythms of ex vivo SCN lacking functional Period1 (Per1 -/-) do not represent the behavioral rhythms of the mutant animals. Surprisingly, in C57BL/6J Per1 -/- mice, the real-time circadian gene promoter activity rhythm is weak or absent in adult SCN slices in vitro even though the free-running wheel-running activity rhythm is indistinguishable from wild-type (Per1 +/+) mice. While some neurons in Per1 -/- SCN explants exhibit robust circadian rhythms, others have irregular and/or low-amplitude rhythms. Together, these data suggest that either a small population of rhythmic neurons in the Per1 -/- SCNis sufficient to control wheel-running activity or that in vivo physiological factors can compensate for the aberrant endogenous rhythms of Per1 -/- SCN.
AB - The mammalian circadian pacemaker in the suprachiasmatic nuclei (SCN) controls daily rhythms of behavior and physiology. Lesions of the SCN cause arrhythmicity of locomotor activity, and transplants of fetal SCN tissue restore rhythmic behavior that is consistent with the periodicity of the donor's genotype, suggesting that the SCN determines the period of the circadian behavioral rhythm. While several studies have demonstrated that the circadian characteristics of in vitro SCN rhythms represent circadian behavior, others have shown that the periods of explanted SCN are not always congruent with locomotor activity. We find that the aberrant rhythms of ex vivo SCN lacking functional Period1 (Per1 -/-) do not represent the behavioral rhythms of the mutant animals. Surprisingly, in C57BL/6J Per1 -/- mice, the real-time circadian gene promoter activity rhythm is weak or absent in adult SCN slices in vitro even though the free-running wheel-running activity rhythm is indistinguishable from wild-type (Per1 +/+) mice. While some neurons in Per1 -/- SCN explants exhibit robust circadian rhythms, others have irregular and/or low-amplitude rhythms. Together, these data suggest that either a small population of rhythmic neurons in the Per1 -/- SCNis sufficient to control wheel-running activity or that in vivo physiological factors can compensate for the aberrant endogenous rhythms of Per1 -/- SCN.
UR - http://www.scopus.com/inward/record.url?scp=70949104144&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=70949104144&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.3261-09.2009
DO - 10.1523/JNEUROSCI.3261-09.2009
M3 - Article
C2 - 19923301
AN - SCOPUS:70949104144
SN - 0270-6474
VL - 29
SP - 14681
EP - 14686
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 46
ER -