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Glutamatergic clock output stimulates melatonin synthesis at night
Stéphanie Perreau-Lenz1, Andries Kalsbeek, Paul Pévet
1Netherlands Institute for Brain Research, Meibergdreef 33, 1105 AZ Amsterdam, the Netherlands. s.perreau@nih.knaw.nl
The European Journal of Neuroscience
|January 17, 2004
Summary
The suprachiasmatic nucleus (SCN) and paraventricular nucleus (PVN) stimulate melatonin synthesis at night. Glutamatergic signaling in the PVN is crucial for this process, highlighting a stimulatory role of the biological clock.
Area of Science:
- Neuroscience
- Chronobiology
- Endocrinology
Background:
- The biological clock in the suprachiasmatic nucleus (SCN) regulates melatonin synthesis in the rat pineal gland.
- Previous research indicated SCN's daytime inhibitory control via the paraventricular nucleus (PVN), but also suggested a stimulatory clock output.
Purpose of the Study:
- To investigate the stimulatory output pathway controlling melatonin rhythm.
- To determine the role of SCN and PVN neuronal activity in melatonin synthesis during the dark phase.
Main Methods:
- Acute in vivo experiments using multiple microdialysis in rats.
- Temporary shutdown of SCN or PVN neuronal activity using tetrodotoxin.
- Application of glutamate antagonist within the PVN to block glutamatergic input.
Main Results:
- Inhibition of SCN or PVN neuronal activity at night decreased melatonin release.
- Blocking glutamatergic input to the PVN significantly reduced melatonin synthesis.
- Neuronal activity in both SCN and PVN is essential for stimulating melatonin production during the night.
Conclusions:
- Neuronal activity of the SCN and PVN is necessary for stimulating melatonin synthesis in the dark period.
- Glutamatergic signaling within the PVN plays a significant role in regulating melatonin synthesis.