Daily Profile of the Extracellular Concentration of Glutamate in the Suprachiasmatic Region of the Siberian Hamster
Interim rept. Jan 1989-Dec 1992
ARMSTRONG LAB BROOKS AFB TX
Pagination or Media Count:
Diurnal patterns of variation in the extracellular concentrations of aspartate, glutamate, and glutamine in the suprachiasmatic nuclei SCN of Djungarian hamsters were determined by in vivo microdialysis. In all hamsters with dialysis probes located in or near the SCN n 5, pronounced diurnal fluctuations in the extracellular concentration of glutamate were observed. Glutamate levels rose gradually during the latter half of the subjective day and through the night to reach peak values at about lights-on. The extracellular concentration of glutamate was significantly elevated p 0.05 during the latter half of the dark phase relative to the level at midday. Diurnal fluctuations were not consistently observed in the concentrations of aspartate and glutamine in SCN dialysates, nor were significant variations observed for any of the three amino acids in dialysates from probes located outside the SCN n 3. The nocturnal rise in extracellular glutamate in the SCN was not attenuated by perfusion with 10 micrometers tetrodotoxin TTX, although this concentration of TTX completely blocked increases in extracellular glutamate caused by simultaneous perfusion with 30 micrometers veratridine. Microdyalisis, Suprachiasmatic nuclei, Glutamic acid, Diurnal rhythm, Djungarian hamsters.
- Genetic Engineering and Molecular Biology
- Medicine and Medical Research