Serotonergic Phase Shifts of the Mammalian Circadian clock: Effects of Tetrodotoxin and High Mg2+
The mammalian circadian clock in the suprachiasmatic nuclei (SCN) can be phase-shifted in vitro by the serotonin agonist quipazine. Here we show that quipazine resets the SCN clock in the presence of tetrodotoxin or 10 mM Mg2+, treatments that block Na+ action potentials and Ca2+ channels, respectively. These results support the hypothesis that quipazine resets the clock by stimulating receptors located on clock elements rather than on cells afferent to the clock.
Rebecca A. Prosser, H. Craig Heller, Joseph D. Miller, Serotonergic phase shifts of the mammalian circadian clock: effects of tetrodotoxin and high Mg2+, Brain Research, Volume 573, Issue 2, 28 February 1992, Pages 336-340, ISSN 0006-8993, DOI: 10.1016/0006-8993(92)90784-7. (http://www.sciencedirect.com/science/article/B6SYR-484DFN0-1NY/2/c68d741e27d12eabe7b9a4873515119d)