Present addresses: Division of Molecular Brain Science, Department of Brain Sciences, Kobe University Graduate School of Medicine, Kobe, Japan. †Division of Psychology, Department of Morphological and Physiological Sciences, Faculty of Medical Sciences, University of Fukui Matsuoka, Eiheiji, Fukui, Japan. ‡Laboratory of Molecular Neuroscience, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan.
Methamphetamine induces circadian oscillation in the brain outside the suprachiasmatic nucleus in rats
Article first published online: 27 MAR 2007
Sleep and Biological Rhythms
Volume 5, Issue 2, pages 132–140, April 2007
How to Cite
MASUBUCHI, S., HONMA, S., ABE, H., NAMIHIRA, M. and HONMA, K.-i. (2007), Methamphetamine induces circadian oscillation in the brain outside the suprachiasmatic nucleus in rats. Sleep and Biological Rhythms, 5: 132–140. doi: 10.1111/j.1479-8425.2007.00263.x
- Issue published online: 27 MAR 2007
- Article first published online: 27 MAR 2007
- Accepted for publication 21 November 2006.
- behavioral rhythm;
Chronic treatment with methamphetamine (MAP) in rats increases the amplitude of locomotor activity rhythm and desynchronizes the activity rhythm from a light–dark cycle. In MAP-treated animals the circadian rhythms in clock gene expressions in the parietal cortex and caudate putamen (CPU) desynchronized from those in the suprachiasmatic nucleus (SCN), the site of a circadian clock. In order to determine whether the 24-h pattern of clock gene expression was due to direct responses of clock genes to MAP treatment or to the oscillations uncoupled or induced by MAP, MAP treatment was terminated when the activity phase of MAP-treated rats was completely desynchronized from a light–dark cycle. In spite of MAP withdrawal, the behavioral as well as Per1, Per2 and DBP expression rhythms in the parietal cortex and CPU still persisted for at least one cycle. However, the rhythm amplitudes were substantially decreased in Per1 and Per2 expression. In contrast, the circadian rhythm of DBP expressions persisted without damping. These data indicate that chronic MAP treatment induced circadian oscillations in Per1 and Per2, in the parietal cortex and CPU, in parallel with the locomotor activity rhythm.