Accession Number : ADA320181

Title :   Study of SCN Neurochemistry using in Vivo Microdialysis in the Conscious Brain: Correlation with Circadian Activity Rhythms.

Descriptive Note : Final technical rept. Dec 92-Jul 96,

Corporate Author : KENT STATE UNIV OH

Personal Author(s) : Glass, J. D.

PDF Url : ADA320181

Report Date : SEP 1996

Pagination or Media Count : 50

Abstract : In recent studies we demonstrated that pretreatment of hamsters with specific 5-HT receptor agonists, or the serotonin (5-HT) precursor, tryptophan, markedly attenuated a variety of light-induced responses of the SCN clock, These included immediate-early gene (Fos) activation in SCN cells, light-mediated SCN field potentials, phase-shifts of the free-running circadian activity rhythm and phase advances of the light-entrained activity rhythm. Based upon these clear and repeatable effects of 5-HT in the SCN, it was hypothesized that 5-HT modulates the effect of light on the timing of circadian physiological and behavioral rhythms. The central findings of the funded studies were that endogenous 5-HT released from terminals within the SCN has physiological roles in: (1) modulating the strength of the photic entraining signal relayed to the SCN from the retina and (2) eliciting phase-shifts in the activity of the circadian clock. These results point to a potentially powerful means of pharmacologically manipulating the human circadian system as a strategy for ameliorating circadian-related disfunctions.

Descriptors :   *BRAIN, *CIRCADIAN RHYTHMS, *NEUROCHEMISTRY, *RETINA, *IN VIVO ANALYSIS, *BIOLOGICAL RHYTHMS, ACTIVATION, CLOCKS, HUMANS, RESPONSE, PHYSIOLOGY, SEROTONIN, BEHAVIOR, DRUGS, REPRODUCIBILITY, HAMSTERS, TRYPTOPHAN.

Subject Categories : Anatomy and Physiology
      Medicine and Medical Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE