BIOLOGY 3UU3 Lecture Notes - Circadian Clock, Vasoactive Intestinal Peptide, Arntl
9 Feb 2013
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Can lead to cardiovascular disease and cancer. Sleep onset is accompanied by increased secretion of growth hormone and prolactin. Although isolated individual scn neurons can act as autonomous circadian clocks, if the balance between vip, gaba and other signaling pathways is disturbed, the core oscillator is disabled. The negative components of the feedback loop are the products of three period (per) and two cryptochrome (cry) genes. Melanopsin a homologue of a photoreceptor in amphibian skin. Melanopsin is expressed in a sub-population of retinal ganglion cells that project directly to the scn and other sites, mediating non-image-forming photoreception. Knock out of the melanopsin gene in mice attenuates circadian and subliminal responses to light in vivo. Exposure to light during circadian night increases the firing rates of scn core neurons. As dawn and dusk move apart in spring, the duration of per expression in the scn lengthens.
