Lithium lengthens the circadian period of individual suprachiasmatic nucleus neurons

Lithium treatment lengthens the period of circadian rhythms in most organis ms. In the present study, we tested whether lithium acts directly on the ma mmalian suprachiasmatic nucleus (SCN) to lengthen rhythms of individual neu rons. Lithium increased the circadian period of firing rate rhythms of cult ured SCN neurons in a concentration-dependent manner. Lithium had no effect on the amplitude of these rhythms, but did affect the period of some cells more than others. The results indicate that lithium acts directly on the S CN to lengthen the free-running period of individual neurons. NeuroReport 1 1:3261-3264 (C) 2000 Lippincott Williams & Wilkins.