Effects of inhibitory and excitatory drugs on the metabolic rhythm of the hamster suprachiasmatic nucleus in vitro

Eur J Pharmacol. 1992 Jun 24;217(1):79-84. doi: 10.1016/0014-2999(92)90514-5.

Abstract

In order to elucidate the role of excitatory and inhibitory transmitters within the suprachiasmatic nucleus (SCN) in the circadian change of 2-deoxyglucose (2-DG) uptake in this nucleus, the effects of 8-hydroxy-2-(di-n-propylamino) tetralin hydrobromide (8-OH-DPAT), muscimol, flurazepam, pentobarbital and glutamate on uptake of 2-DG by hamster SCN were examined in hypothalamic slice preparations. 2-DG uptake in the SCN was high during the subjective day and low during the subjective night. The high uptake of 2-DG in the SCN during the daytime was inhibited by the superfusion of 8-OH-DPAT, muscimol, flurazepam and pentobarbital in a dose-dependent manner, but the low uptake of 2-DG during the night was unaffected. The low uptake during the night was significantly increased by treatment with glutamate, whereas 2-DG uptake during the day was unaffected. In contrast to the above results, 20 mM KCl and 1 microM tetrodotoxin increased and decreased 2-DG uptake during both the day and night, respectively. The present results strongly suggest that agonists of 5-HT1A receptors and GABAA-benzodiazepine-barbiturate complex receptors regulate the function of the SCN through their inhibitory action on 2-DG uptake during the day, and that glutamate also regulates SCN function through it stimulatory action on 2-DG uptake during the night.

Publication types

  • Comparative Study

MeSH terms

  • 8-Hydroxy-2-(di-n-propylamino)tetralin / pharmacology
  • Animals
  • Circadian Rhythm / drug effects*
  • Circadian Rhythm / physiology
  • Cricetinae
  • Deoxyglucose / pharmacokinetics
  • Dose-Response Relationship, Drug
  • Flurazepam / pharmacology
  • Glutamates / pharmacology
  • Glutamic Acid
  • Male
  • Mesocricetus
  • Muscimol / pharmacology
  • Neurons / drug effects
  • Pentobarbital / pharmacology
  • Potassium Chloride / pharmacology
  • Suprachiasmatic Nucleus / drug effects
  • Suprachiasmatic Nucleus / metabolism*
  • Tetrodotoxin / pharmacology

Substances

  • Glutamates
  • Muscimol
  • Glutamic Acid
  • Tetrodotoxin
  • Potassium Chloride
  • 8-Hydroxy-2-(di-n-propylamino)tetralin
  • Deoxyglucose
  • Pentobarbital
  • Flurazepam