The effects of chronic administration of methamphetamine on circadian rhythm of mice

The suprachiasmatic nucleus (SCN) orchestrates synchrony among many peripheral oscillators and and is required for circadian rhythms of locomotor activity and many physiological processes. However, chronic administration of methamphetamine (MAP) treatment dramatically lengthens circadian period of locomotor activity rhythms and induces rhythms in animals lacking SCN. These unique effects of MAP on circadian behavior suggest methamphetamine-sensitive circadian oscillator (MASCO). At present, the anatomical substrate and the molecular components of the MASCO are unknown.