L. Bitting et al., C-FOS MESSENGER-RNA INCREASES IS THE GROUND-SQUIRREL SUPRACHIASMATIC NUCLEUS DURING AROUSAL FROM HIBERNATION, Neuroscience letters, 165(1-2), 1994, pp. 117-121
During hibernation the body temperature of the golden-mantled ground s
quirrel, Spermophilus lateralis, may drop below 5 degrees C for a few
hours to a week or more. Animals cycle between euthermia and deep hibe
rnation many times over the course of the hibernation season. Expressi
on of the transcription factor c-fos increased in the suprachiasmatic
nucleus (SCN) of the hypothalamus, the mammalian circadian clock, duri
ng deep hibernation and peaked during the arousal from hibernation. Th
e pattern of increase in c-fos messenger RNA seen in the SCN by in sit
u hybridization was similar to that seen by Northern blot analysis of
total hypothalamic RNA. The induction of c-Sos may reflect a wake-up s
ignal, increasing transcription of genes required in the euthermic sta
te.