Circadian profile of Per gene mRNA expression in the suprachiasmatic nucleus, paraventricular nucleus, and pineal body of aged rats

J Neurosci Res. 2001 Dec 15;66(6):1133-9. doi: 10.1002/jnr.10010.


Aging alters circadian components such as the free-running period, the day-to-night activity ratio and photic entrainment in behavioral rhythms, and 2-deoxyglucose uptakes and neuronal firing in the suprachiasmatic nucleus (SCN). A core clock mechanism in the mouse SCN appears to involve a transcriptional feedback loop in which Period (Per) and Cryptochrome (Cry) genes play a role in negative feedback. The circadian rhythm systems include photic entrainment, clock oscillation, and outputs of clock information such as melatonin production. In this experiment, we examined clock gene expression to determine whether circadian input, oscillation, and output are disrupted with aging. Circadian expression profiles of rPer1, rPer2, or rCry1 mRNA were very similar in the SCN, the paraventricular nucleus of the hypothalamus (PVN), and the pineal body of young and aged (22-26 months) rats. On the other hand, the photic stimulation-induced rapid expression of Per1 and Per2 in the SCN was reduced with aging. The present results suggest that the molecular mechanism of clock oscillation in the SCN, PVN, and pineal body is preserved against aging, whereas the impairment of Per1 induction in the SCN after light stimulation may result in impaired behavioral photic entrainment in aged rats.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / genetics*
  • Animals
  • Biological Clocks / genetics
  • Cell Cycle Proteins
  • Circadian Rhythm / genetics*
  • Cryptochromes
  • Darkness
  • Drosophila Proteins*
  • Eye Proteins*
  • Flavoproteins / genetics
  • Gene Expression Regulation / physiology*
  • Male
  • Nuclear Proteins / genetics*
  • Paraventricular Hypothalamic Nucleus / metabolism*
  • Period Circadian Proteins
  • Photic Stimulation
  • Photoreceptor Cells, Invertebrate*
  • Pineal Gland / metabolism*
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Receptors, G-Protein-Coupled
  • Suprachiasmatic Nucleus / metabolism*
  • Transcription Factors


  • Cell Cycle Proteins
  • Cryptochromes
  • Drosophila Proteins
  • Eye Proteins
  • Flavoproteins
  • Nuclear Proteins
  • PER1 protein, human
  • Per1 protein, mouse
  • Per1 protein, rat
  • Per2 protein, mouse
  • Per2 protein, rat
  • Period Circadian Proteins
  • RNA, Messenger
  • Receptors, G-Protein-Coupled
  • Transcription Factors
  • cry protein, Drosophila