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In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells
Published on: September 28, 2017
The methamphetamine-sensitive circadian oscillator does not employ canonical clock genes
Jennifer A Mohawk1, Matthew L Baer, Michael Menaker
1Department of Biology, University of Virginia, Charlottesville VA 22904, USA.
Abstract:
The "master clock" in the suprachiasmatic nucleus (SCN) of the hypothalamus controls most behavioral, physiological, and molecular circadian rhythms in mammals. However, there are other, still unidentified, circadian oscillators that are able to carry out some SCN functions. Here we show that one of these, the methamphetamine-sensitive circadian oscillator (MASCO), which generates behavioral rhythms in the absence of the SCN, is based on an entirely different molecular mechanism. We tested mice lacking, or with mutations of, genes that form the canonical circadian machinery. In all cases, animals that were arrhythmic as a consequence of genetic defect expressed circadian locomotor rhythms when treated with methamphetamine. These results strongly support the hypothesis that the mechanism generating MASCO does not involve the molecular feedback loops that underlie canonical circadian rhythmicity. The properties of MASCO may provide insight into the evolution of circadian mechanisms. Importantly, MASCO may play a role in addiction to psychostimulants.
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