TY - JOUR
T1 - Interaction of the retina with suprachiasmatic pacemakers in the control of circadian behavior
AU - Yamazaki, Shin
AU - Alones, Vinessa
AU - Menaker, Michael
PY - 2002/8/1
Y1 - 2002/8/1
N2 - The suprachiasmatic nucleus (SCN) is the central circadian pacemaker governing the circadian rhythm of locomotor activity in mammals. The mammalian retina also contains circadian oscillators, but their roles are unknown. To test whether the retina influences circadian rhythms of locomotor behavior, the authors compared the activity of bilaterally enucleated hamsters with the activity of intact controls held in constant darkness (DD). Enucleated hamsters showed a broader range of free-running periods (T) than did intact hamsters held for the same length of time in DD. This effect was independent of the age at enucleation (on postnatal days 1, 7, or 28). The average T of intact animals kept in DD from days 7 or 28 was significantly longer than that of intact animals kept in DD from day 1 or any of the enucleated groups. This indicates that early exposure to light-dark cycles lengthens the T and that the eye is required to maintain this effect even in DD. These data suggest that hypothalamic circadian pacemakers may interact continuously with the retina to determine the T of locomotor activity. Enucleation caused a large decrease in glial fibrillary acidic protein in the SCN but has no (or slight) effects on calbindin, neuropeptide Y, vasopressin, or vasoactive intestinal polypeptide, which suggests that enucleation does not produce major damage to the SCN, an interpretation that is supported by the fact that enucleated animals retain robust circadian rhythmicity. The presence of an intact retina appears to contribute to system-level circadian organization in mammals perhaps as a consequence of interaction between its circadian oscillators and those in the SCN.
AB - The suprachiasmatic nucleus (SCN) is the central circadian pacemaker governing the circadian rhythm of locomotor activity in mammals. The mammalian retina also contains circadian oscillators, but their roles are unknown. To test whether the retina influences circadian rhythms of locomotor behavior, the authors compared the activity of bilaterally enucleated hamsters with the activity of intact controls held in constant darkness (DD). Enucleated hamsters showed a broader range of free-running periods (T) than did intact hamsters held for the same length of time in DD. This effect was independent of the age at enucleation (on postnatal days 1, 7, or 28). The average T of intact animals kept in DD from days 7 or 28 was significantly longer than that of intact animals kept in DD from day 1 or any of the enucleated groups. This indicates that early exposure to light-dark cycles lengthens the T and that the eye is required to maintain this effect even in DD. These data suggest that hypothalamic circadian pacemakers may interact continuously with the retina to determine the T of locomotor activity. Enucleation caused a large decrease in glial fibrillary acidic protein in the SCN but has no (or slight) effects on calbindin, neuropeptide Y, vasopressin, or vasoactive intestinal polypeptide, which suggests that enucleation does not produce major damage to the SCN, an interpretation that is supported by the fact that enucleated animals retain robust circadian rhythmicity. The presence of an intact retina appears to contribute to system-level circadian organization in mammals perhaps as a consequence of interaction between its circadian oscillators and those in the SCN.
KW - Calbindin
KW - Circadian
KW - Glial fibrillary acidic protein
KW - Hamster
KW - Retina
KW - Serotonin
KW - Suprachiasmatic nucleus
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U2 - 10.1177/074873040201700405
DO - 10.1177/074873040201700405
M3 - Article
C2 - 12164248
AN - SCOPUS:85047686921
SN - 0748-7304
VL - 17
SP - 315
EP - 329
JO - Journal of Biological Rhythms
JF - Journal of Biological Rhythms
IS - 4
ER -