Two circadian oscillatory mechanisms in the mammalian retina

Neuroreport. 2000 Dec 18;11(18):3995-7. doi: 10.1097/00001756-200012180-00018.


To investigate the mechanism that controls circadian rhythms in the mammalian retina, we examined the mRNA expression rhythms of serotonin N-acetyltransferase (NAT), the mammalian clock gene rPer2 and a clock-controlled gene Dbp in the retina of rats with lesions of the suprachiasmatic nucleus (SCN), the master clock in mammals. Northern blot analyses showed that retinal NAT mRNA still exhibited the circadian expression in the SCN-lesioned rats, whereas the lesion abolished the rhythms of rPer2 and Dbp mRNAs. These findings suggest that the mammalian retina has two circadian oscillatory mechanisms: one can generate rhythmicity independent of the SCN and the other requires the SCN to maintain circadian oscillation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arylamine N-Acetyltransferase / genetics
  • Biological Clocks / genetics*
  • Cell Cycle Proteins
  • Circadian Rhythm / genetics*
  • DNA-Binding Proteins*
  • Male
  • Molecular Sequence Data
  • Nuclear Proteins / genetics
  • Period Circadian Proteins
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Retina / cytology
  • Retina / metabolism*
  • Suprachiasmatic Nucleus / cytology
  • Suprachiasmatic Nucleus / physiology
  • Suprachiasmatic Nucleus / surgery
  • Transcription Factors / genetics


  • Cell Cycle Proteins
  • DBP protein, rat
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Per2 protein, rat
  • Period Circadian Proteins
  • RNA, Messenger
  • Transcription Factors
  • Arylamine N-Acetyltransferase

Associated data

  • GENBANK/AB016532
  • GENBANK/J03179
  • GENBANK/U18913