Control of Rest:Activity by a Dopaminergic Ultradian Oscillator and the Circadian Clock

Abstract

There is long-standing evidence for rhythms in locomotor activity, as well as various other aspects of physiology, with periods substantially shorter than 24 h in organisms ranging from fruit flies to humans. These ultradian oscillations, whose periods frequently fall between 2 and 6 h, are normally well integrated with circadian rhythms; however, they often lack the period stability and expression robustness of the latter. An adaptive advantage of ultradian rhythms has been clearly demonstrated for the common vole, suggesting that they may have evolved to confer social synchrony. The cellular substrate and mechanism of ultradian rhythm generation have remained elusive so far, however recent findings—the subject of this review—now indicate that ultradian locomotor rhythms rely on an oscillator based on dopamine, dubbed the dopaminergic ultradian oscillator (DUO). These findings also reveal that the DUO period can be lengthened from <4 to >48 h by methamphetamine treatment, suggesting that the previously described methamphetamine-sensitive (circadian) oscillator represents a long-period manifestation of the DUO.

Applying machine learning in motor activity time series of depressed bipolar and unipolar patients compared to healthy controls

“…Motor activity is indisputably an articulation of repeated daily social rhythms in interaction with cyclical biological rhythms, driven by the 24-hour circadian clock interlocked with numerous ultradian rhythmic cycles of 2 to 6 hours [9]. Out of sync biological rhythmic patterns are suggested as essential symptoms of mood episodes [10].…”

Evidence for a Coupled Oscillator Model of Endocrine Ultradian Rhythms

“…This knowledge has facilitated translational breakthroughs, exemplified by personalized chronotherapy, for example, in which the timing of pharmaceutical administration is aligned to the patient’s circadian peak of receptivity to treatment (Giacchetti et al, 2006; Lévi et al, 2010). Whereas ultradian variation also provides clinically relevant information (Hompes et al, 1992; Sturis et al, 1992) and has long been suggested to be central to mammalian physiology (Brandenberger et al, 1987; Lloyd, 1992; Miyata et al, 2016; Veldhuis et al, 2008), there is no single accepted systems-level framework to unify the study of ultradian rhythms (URs) at the organismal level (Bashan et al, 2012; Bourguignon and Storch, 2017; Prendergast and Zucker, 2016). Because of the absence of a unifying framework, as well as the technical challenges of measuring endocrine systems at ultradian timescales, circadian studies outnumber ultradian studies nearly 32:1 (Landgraf et al, 2014; Prendergast and Zucker, 2016).…”

Effects of autonomic denervations on the rhythms in axial length and choroidal thickness in chicks

“…The most commonly studied are rhythms in locomotor activity, sleep, feeding, body temperature and hormone levels. In general, their periods are less stable than circadian ones, and can be altered by variations in external cues that are unrelated to the light/dark cycle (reviews: (Blessing and Ootsuka 2016;Bourguignon and Storch 2017). Of relevance to our current findings, there is an ultradian component (1.875 cycles/day) in the endogenous circadian rhythm in scleral proteoglycan synthesis in isolated chick scleras from fast-growing myopic eyes that is not as prevalent in normallygrowing eyes (Nickla et al 1999).…”