title: Learned motivation drives circadian physiology in the absence of the master circadian clock.
abstract: The suprachiasmatic nucleus (SCN)-often referred to as the master circadian clock-is essential in generating physiologic rhythms and orchestrating synchrony among circadian clocks. This study tested the hypothesis that periodic motivation induced by rhythmically pairing 2 reinforcing stimuli [methamphetamine (Meth) and running wheel (RW)] restores autonomous circadian activity in arrhythmic SCN-lesioned (SCNX) C3H/HeN mice. Sham-surgery and SCNX mice were treated with either Meth (1.2 mg/kg, i.p.) or vehicle in association, dissociation, or absence of an RW. Only the association of Meth treatment and restricted RW access successfully reestablished entrained circadian rhythms in mice with SCNX. RW-likely acting as a link between the circadian and reward systems-promotes circadian entrainment of activity. We conclude that a conditioned drug response is a powerful tool to entrain, drive, and restore circadian physiology. Furthermore, an RW should be recognized as a potent input signal in addition to the conventional use as an output signal.-Rawashdeh, O., Clough, S. J., Hudson, R. L., Dubocovich, M. L. Learned motivation drives circadian physiology in the absence of the master circadian clock.
authors.affiliation: Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.
authors.forename: Oliver
authors.initials: O
authors.lastname: Rawashdeh
authors.affiliation: Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.
authors.forename: Shannon J
authors.initials: SJ
authors.lastname: Clough
authors.affiliation: Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
authors.forename: Randall L
authors.initials: RL
authors.lastname: Hudson
authors.affiliation: Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA; mdubo@buffalo.edu.
authors.forename: Margarita L
authors.initials: ML
authors.lastname: Dubocovich
mesh_terms: D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D007858:Learning / Q000502:physiology*; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D009042:Motivation / Q000187:drug effects / Q000502:physiology*; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D013493:Suprachiasmatic Nucleus / Q000473:pathology* / Q000502:physiology
chemical_list: D000697:Central Nervous System Stimulants; D008694:Methamphetamine
keywords: SCN lesions; methamphetamine; running wheel