Accession Number : ADA259803


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


Descriptive Note : Final rept. 1 Nov 89-31 Oct 92,


Corporate Author : KENT STATE UNIV OH


Personal Author(s) : Glass, J D ; Hauser, U E ; Randolph, W ; Ferriera, S ; Rea, M A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a259803.pdf


Report Date : 29 Dec 1992


Pagination or Media Count : 15


Abstract : The central aim of this research is to provide information on the neurochemical processes that underlie the generation and entrainment of mammalian circadian rhythms. The studies are centered around the newly-developed in vivo brain microdialysis technique for assessing the daily patterns of neurotransmitter release in the suprachiasmatic nuclei (SCN) of freely-behaving hamsters. During the funded period, this approach has yielded several new findings related to the activities of serotonergic and excitatory amino acid systems in the SCN. Specifically, it was found that: there are daily variations in extracellular concentrations of 5-HIAA and glutamate in the SCN, with highest levels occurring at night; the daily release pattern of glutamate, but not serotonin, in the SCN is circadian in nature; the rhythm in glutamate measured in SCN microdialysate is based upon a non-synaptic, calcium-dependent mechanism and does not appear to be directly linked to the expression of locomotory behavior; and serotonergic transmission suppresses glutamate in SCN microdialysate, an effect possibly related to a modulatory effect of serotonin on glutamate release in the SCN. This also may be closely related to our finding that serotonin blocks light-induced Fos protein expression in the SCN.


Descriptors :   *CIRCADIAN RHYTHMS , *IN VIVO ANALYSIS , *NEUROCHEMICAL TRANSMISSION , BRAIN , PROTEINS , IN VITRO ANALYSIS , VARIATIONS , NEUROTRANSMITTERS , HAMSTERS , SYNAPSIS , PACEMAKERS , AMINO ACIDS , SEROLOGY , RELEASE , PATTERNS , SEROTONIN , BEHAVIOR , CALCIUM COMPOUNDS


Subject Categories : Biochemistry
      Anatomy and Physiology


Distribution Statement : APPROVED FOR PUBLIC RELEASE