Melanopsin

Melanopsin is a protein of the opsin family, which was first identified in frogs as part of Lumineszenzwahrnehmung. It occurs in frogs in the melanocytes of the skin, eyes and brain. In humans, it was found only in nerve cells of the eye, where it is used for playing the ambient brightness. Their signals contribute to the synchronization of the circadian rhythm in with the natural day-night cycle or the social day -night rhythm and in addition also the pupillary reflex.

In the retina of the eye it is produced in a subset of retinal ganglion cells ( RGCs ), and they themselves are light- sensitive. About axons, the pull of the hypothalamus directly to the nuclei suprachiasmatici ( SCN ), sending this photo sensitives ganglion cells lasting, the brightness reflecting signals that are interpreted as a timer for timing sign endogenous rhythms. Investigations showed in particular the importance of melanopsin for light-dependent suppression of melatonin secretion in the pineal gland, and thus its relation to tasks of internal clock.

Human Genome Organisation Suprachiasmatic nucleus Intrinsically photosensitive retinal ganglion cells Zeitgeber
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