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Circadian Rhythm Research Paper

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There are many factors that contribute to the regulation of the circadian rhythm. For the purpose of this essay, focus will be placed on genetic regulation, the role of melatonin, and environmental regulation, with examples discussed in each.

To fully understand the regulation of the circadian rhythm, it is important to discuss the genetics that underlie its function. The generation of the circadian rhythm can be found in the neurons of the SCN, which is controlled by a transcriptional feedback loop. This feedback loop allows the rhythm to adjust to various environmental changes1. The genes that are primarily responsible for the circadian rhythm include: period genes, cryptochrome genes, Bmal1, and clock gene1, 8, 9. Mutations of these genes can lead to desynchronization of the rhythm.

To begin the transcription process, CLOCK and BMAL1 form a heterodimeric transcriptional activator so that three Period genes and two Cryptochrome genes can be transcribed: Per1, Per2, Per3, and Cry1 and Cry2, respectively10, 11. To stop the transcription of the Per and Cry genes, a PER:CRY heterodimer will form and move back to the nucleus and act on CLOCK:BMAL1 to repress transcription of Per and Cry. The regulatory …show more content…

Its synthesis is restricted to the night and its secretion is inhibited by light. Once synthesized, melatonin acts on specific receptors within the body. Depending on the cell type, melatonin will initiate different signaling pathways. G-coupled receptors, MT(1) and MT(2), are both coupled to cyclic adenosine monophosphate (cAMP) and calcium, however MT(2) is also linked to cyclic guanosine monophosphate (cGMP). Interestingly, receptors for melatonin have been found in numerous peripheral tissues, in addition to receptors in the central nervous system12. Likewise, melatonin influences rhythmic release of thyroid, growth, and hypophysogonadal

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