Neuropharmacology of Circadian Phase Regulation by Serotonin
Abstract
This work elucidates the mechanism by which serotonin regulates the circadian clock's response to%the phase-adjusting effects of exposure to light. The primary goals are (1) to identify% and characterize the neural receptors that mediate these phase-shifting responses, and (2) to determine their sites of action. Using the Syrian hamster, we cloned and characterized the 5-HT1A and 5-HT7 receptors. We then demonstrated that these receptors are present in the suprachiasmatic nucleus (SCN). We sought to determine serotonin receptor mRNA in identified cells within the SCN and retina, but neither of two approaches was successful during the funding period. We studied the effects of various serotonin receptor agonists and antagonists. Results indicate that presynaptic 5-HT1B receptors on retinal terminals in the SCN attenuate the effect of light on melatonin production in the pineal gland, as well as the effect of light on circadian phase. We published three studies on the role of adenosine in the regulation of light-induced phase shifts, and found that blocking Al AR in the SCN promotes wakefulness. Our other studies have begun to elucidate the gene control of signaling cascades in the SCN, and show that light exposure activates distinct cascades in distinct cell groups.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2002
- Accession Number
- ADA419071
Entities
People
- Michael A. Rea
Organizations
- University of Houston