The clock in the dorsal suprachiasmatic nucleus runs faster than that in the ventral

In mammals, circadian rhythms are driven by a pacemaker located in the suprachiasmatic nuclei (SCN) of the hypothalamus. The pacemaker is composed of an ensemble of multiple, single‐cell oscillators in the SCN. We measured arginine–vasopressin (AVP) release in organotypic SCN slices. The SCN slice culture showed circadian oscillation of AVP release with a period length (± SEM) of 23.84 ± 00.03 h. This period is very similar to the one we previously reported in dispersed SCN cultures and is also close to that of behavioural rhythms. When the ventral part was removed by a surgical cut across the slice in the horizontal plane, however, the period became shorter (23.22 ± 00.08 h). On the other hand, the removal of the dorsal part did not affect period length. These results suggest that the oscillators in ventral and dorsal cells contribute differently to period length and that the dorsal oscillators are entrained by the ventral ones to form a single integrated oscillator.

[1]  J. Vanecek,et al.  Melatonin inhibits spontaneous and VIP-induced vasopressin release from suprachiasmatic neurons , 1998, Brain Research.

[2]  H. Okamura,et al.  Organotypic slice culture of the rat suprachiasmatic nucleus: Sustenance of cellular architecture and circadian rhythm , 1994, Neuroscience.

[3]  Yasufumi Shigeyoshi,et al.  An Abrupt Shift in the Day/Night Cycle Causes Desynchrony in the Mammalian Circadian Center , 2003, The Journal of Neuroscience.

[4]  S. Shibata,et al.  Electrical and metabolic activity of suprachiasmatic nucleus neurons in hamster hypothalamic slices , 1988, Brain Research.

[5]  A. Miyawaki,et al.  Circadian Dynamics of Cytosolic and Nuclear Ca2+ in Single Suprachiasmatic Nucleus Neurons , 2003, Neuron.

[6]  Kazuyuki Shinohara,et al.  Circadian rhythms in the release of vasoactive intestinal polypeptide and arginine-vasopressin in organotypic slice culture of rat suprachiasmatic nucleus , 1994, Neuroscience Letters.

[7]  Rae Silver,et al.  Localization of a Suprachiasmatic Nucleus Subregion Regulating Locomotor Rhythmicity , 1999, The Journal of Neuroscience.

[8]  A. Harmar.  An Essential Role for Peptidergic Signalling in the Control of Circadian Rhythms in the Suprachiasmatic Nuclei , 2003, Journal of neuroendocrinology.

[9]  J. Meijer,et al.  Neurophysiology of the suprachiasmatic circadian pacemaker in rodents. , 1989, Physiological reviews.

[10]  N. Ishida,et al.  Anisomycin induces phase shifts of circadian pacemaker in primary cultures of rat suprachiasmatic nucleus , 1995, Brain Research.

[11]  N. Murakami,et al.  Long-term cultured neurons from rat suprachiasmatic nucleus retain the capacity for circadian oscillation of vasopressin release , 1991, Brain Research.

[12]  Steven H. Strogatz,et al.  Cellular Construction of a Circadian Clock: Period Determination in the Suprachiasmatic Nuclei , 1997, Cell.

[13]  I. Zucker,et al.  Circadian rhythms in drinking behavior and locomotor activity of rats are eliminated by hypothalamic lesions. , 1972, Proceedings of the National Academy of Sciences of the United States of America.

[14]  N. Koibuchi,et al.  Circadian rhythms of vasopressin release in primary cultures of rat suprachiasmatic nucleus , 1993, Brain Research.

[15]  Sato Honma,et al.  Circadian periods of single suprachiasmatic neurons in rats , 1998, Neuroscience Letters.

[16]  Markus Meister,et al.  Individual neurons dissociated from rat suprachiasmatic nucleus express independently phased circadian firing rhythms , 1995, Neuron.

[17]  William J. Schwartz,et al.  Morning and evening circadian oscillations in the suprachiasmatic nucleus in vitro , 2000, Nature Neuroscience.

[18]  R. Leak,et al.  Suprachiasmatic nucleus organization , 2002, Cell and Tissue Research.

[19]  S. Yamaguchi,et al.  Synchronization of Cellular Clocks in the Suprachiasmatic Nucleus , 2003, Science.