Memory on long but not on short days is stored in the rat suprachiasmatic nucleus.
In order to follow adjustment of the rat circadian pacemaking system to a change of the photoperiod, the rhythm in the light-induced c-fos expression was used as a marker of the intrinsic rhythmicity of the suprachiasmatic nucleus (SCN). After a change from a long photoperiod with 16 h of light per day to a short one with 8 h of light, the interval enabling high c-fos photoinduction decompressed gradually and the full extension by 5-6 h was achieved only within 2 weeks. After a change from a short to a long photoperiod, the interval was compressed by 5-6 h within 3 days. The data indicate a rapid adjustment of the photoperiod dependent-state of the SCN pacemaker to long days but only a slow one to short days.
Sumová
A
A
Institute of Physiology, Academy of Sciences of the Czech Republic, Prague.
Trávnícková
Z
Z
Illnerová
H
H
D000818:Animals; D015415:Biomarkers; D007150:Immunohistochemistry; D008297:Male; D008568:Memory / Q000502:physiology*; D017440:Photoperiod; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D013493:Suprachiasmatic Nucleus / Q000502:physiology*
D015415:Biomarkers; D016760:Proto-Oncogene Proteins c-fos