Serotonergic phase shifts of the mammalian circadian clock: effects of tetrodotoxin and high Mg2+

Brain Res. 1992 Feb 28;573(2):336-40. doi: 10.1016/0006-8993(92)90784-7.

Abstract

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.

MeSH terms

  • Animals
  • Brain / drug effects
  • Brain / physiology*
  • Circadian Rhythm / drug effects*
  • In Vitro Techniques
  • Magnesium / pharmacology*
  • Male
  • Neurons / drug effects
  • Neurons / physiology*
  • Potassium Channels / drug effects
  • Potassium Channels / physiology
  • Quipazine / pharmacology*
  • Rats
  • Rats, Inbred Strains
  • Serotonin / physiology
  • Sodium / pharmacology
  • Tetrodotoxin / pharmacology*

Substances

  • Potassium Channels
  • Serotonin
  • Tetrodotoxin
  • Quipazine
  • Sodium
  • Magnesium