Circadian activity rhythm in methamphetamine-treated Clock mutant mice.
It is well established that the Clock gene is essential for expressing circadian activity rhythms in mammals under constant darkness. The Clock gene product is a positive component of a molecular feedback loop which is assumed to generate the circadian rhythm. On the other hand, chronic treatment of methamphetamine (MAP) induces locomotor activity rhythm in a circadian domain, which is independent of the suprachiasmatic nucleus (SCN) and is driven by a pacemaker outside the SCN. However, it is not known whether the pacemaker outside the SCN possesses a similar molecular mechanism to that in the SCN. Here we show that MAP restores locomotor activity rhythm in arrhythmic homozygous Clock mutant (Clock/Clock) mice under constant darkness. This result indicates that the Clock mutation does not affect the MAP-induced locomotor rhythm.
Masubuchi
S
S
Department of Physiology, Hokkaido University Graduate School of Medicine, N-15, W-7, Kita-ku, Sapporo 060-8638, Japan.
Honma
S
S
Abe
H
H
Nakamura
W
W
Honma
K
K
D000818:Animals; D001683:Biological Clocks / Q000187:drug effects* / Q000235:genetics; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D056926:CLOCK Proteins; D002940:Circadian Rhythm / Q000187:drug effects* / Q000235:genetics; D008694:Methamphetamine / Q000494:pharmacology*; D051379:Mice; D008817:Mice, Mutant Strains; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009154:Mutation / Q000187:drug effects* / Q000502:physiology; D015534:Trans-Activators / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
D015534:Trans-Activators; D008694:Methamphetamine; D056926:CLOCK Proteins; C538944:Clock protein, mouse