Regulation and Synchronization of the Master Circadian Clock by Purinergic Signaling from Suprachiasmatic Nucleus Astrocytes

作者：Alisa D. Womac · 发表于：OakTrust (Texas A&M University Libraries) · 年份：2012 · 研究领域：Circadian rhythm and melatonin、Photoreceptor and optogenetics research

Molecular, cellular, and physiological processes within an organism are set to occur at specific times throughout the day. The timing of these processes is under control of a biological clock. Nearly all organisms on Earth have biological clocks, ranging from unicellular bacteria and fungi to multicellular plants, insects, reptiles, fish, birds, and mammals. The biological clock is an endogenous time-keeping mechanism that generates the onset of many processes and coordinates the phases of processes over 24 hours. While the biological clock allows these organisms to maintain roughly 24-hour, or circadian, timing in daily processes, many organisms have the ability to set their clocks, or entrain them, to changes in light. In mammals, the suprachiasmatic nucleus (SCN) is the master biological clock that entrains daily physiological and behavioral rhythms to the appropriate times of day and night. 
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\nThe SCN is located in the hypothalamus and contains thousands of neurons and glia that function in coordinating system-level physiological rhythms that are entrained to environmental light cues. Many of these neurons and glia are individual circadian oscillators, and the cellular mechanisms that couple them into ensemble oscillations are emerging. Adenosine triphosphate (ATP) is a transmitter involved in local communication among astrocytes and between astrocytes and neurons. ATP released from astrocytes may play a role in SCN cellular communication and synchrony. 
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