Rat photoreceptor circadian oscillator strongly relies on lighting conditions

• DOI: 10.1111/j.1460-9568.2011.07772.x
• Publication Date: 2011-07-20T02:38:53Z
• Authors: Cristina Sandu; David Hicks; Marie-Paule Felde...
• Keywords: PER2; PER1; Oscillating gene; Darkness; Melanopsin

Mammalian retina harbours a self-sustained circadian clock able to synchronize the light : dark (LD) cycle and drive cyclic outputs such as night-time melatonin synthesis. Clock genes are expressed in distinct parts of tissue, it is presently assumed that contains several oscillators. However, molecular organization cell type-specific clockworks has been poorly investigated. Here, we questioned presence rat photoreceptors by studying 24-h kinetics output gene expression whole photoreceptor layers isolated vibratome sectioning. To address importance stimulation towards properties, animals were exposed 12 h LD or 36 constant darkness. Clock, Bmal1, Per1, Per2, Cry1, Cry2, RevErbα Rorβ all found be display rhythmic transcription cycle. retinas, used reference, also showed with marked similarity profiles pure photoreceptors. In contrast, oscillations no longer detectable after darkness, exception Cry2 Rorβ. Importantly, transcripts from two well-characterized genes, Aanat (arylalkylamine N-acetyltransferase) c-fos, retained sustained rhythmicity. We conclude contain core machinery oscillator likely operative under exposure Constant darkness dramatically alters clockwork functions might then rely on inputs extra-photoreceptor