Vision, Light, and Circadian Clock

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Since my last post regarding the paper that studied the sleep of the zebrafish, I was keep thinking of the role of light and photoreceptor in our physiological control. There is a paper in Cell focusing on circadian clock, retina, and vision processing.

Storch K-F et al. first confirmed the intrinsic circadian clock of retina, by whole-genome microarray obtained from whole eyes, with the scenario of constant darkness, or 12:12 hr light-dark cycle.

Then using mice lacking Bmal1, either retina-specific or in all tissue, the authors showed that the gene expression rhythm was wildly disturbed, even the light-dark interval was given. This underscored the autonomy of the local intrinsic circadian clock within the eyes.

On the histology aspect, however, the retinas of these mice with either globally or locally targeted Bmal1 gene, appeared structurally normal by light microscopy, and further by electron microscopy.

The authors then turned to electrophysiological studies. Employing electroretinogram (ERG), they found both the Bmal1-deleted mice manifested defective inner retinal electrical responses to light, but the photoreceptor response was normal. This virtually suggests that the intrinsic circadian clock of the retina may be involved in vision processing.

Back to my original question, do zebrafish have intrinsic clock in her eyes? Or it is overwhelmed by the light?

Wilfred Wu Wonderland [ Portal | 1996 edition | 2001 edition | 2006 Blog ]
Tags: Circadian Clock, Circadian rhythm, Vision, Environment, Developmental Biology, Neurology, Ophthalmology, Molecular Biology, Physiology, Electrophysiology, Histology, Whole Genome Microarray, Bioinformatics, ERG, Retina, Medicine, Medical Science, Biomedical Science, Biological Science, Medicine-Ophtalmology, Medicine-Neurology, Medicine-Developmental Biology, Medicine-Molecular Biology, Medicine-Genetics