Accession Number : ADA337450

Title :   Control of Circadian Behavior by Transplanted Suprachiasmatic Nuclei and by the Tau Gene.

Descriptive Note : Final rept. 1 Sep 94-31 Aug 97

Corporate Author : VIRGINIA UNIV CHARLOTTESVILLE DEPT OF BIOLOGY

Personal Author(s) : Menaker, Micahel

PDF Url : ADA337450

Report Date : AUG 1997

Pagination or Media Count : 17

Abstract : The mammalian retina was found to contain an independent circadian oscillator which regulates the synthesis of melatonin and has effects, through a presently unknown pathway, on the circadian rhythm of locomotor behavior in infact animals. Electrical recordings were successfully obtained from several brain regions of intact, behaving hamsters. The suprachiasmatic nucleus (SCN) expressed circadian rhythms of electrical activity with peak electrical activity during the animals' 'day' (inactive period), and low activity during the animals' night (active period). The electrical activity in the bed nucleus of the stria terminalis was in phase with that in the SCN. All other brain regions studied showed electrical rhythms with the opposite phase. The circadian mutation tau was found to affect the period and the temperature compensation mechanism of the oscillator in the cultured retina as well as the dynamics of c-fos induction in the SCN. Tau mutant hamsters were found to have significantly altered responses of their circadian rhythms to GABAergic pharmacological agents. A model system was developed (using the green iguana) with which it is possible, for the first time, to study the interaction of multiple, distributed circadian oscillators. This is the only available experimental model of human circadian dissociation.

Descriptors :   *CIRCADIAN RHYTHMS, *MAMMALS, *GENES, *MELATONIN, OSCILLATORS, PEAK VALUES, TEMPERATURE, BRAIN, DISTRIBUTION, HUMANS, SYNTHESIS, ELECTRICAL PROPERTIES, MUTATIONS, RESPONSE, ANIMALS, RECORDING SYSTEMS, BEHAVIOR, RETINA, DRUGS, DISSOCIATION, HAMSTERS, LOCOMOTION.

Subject Categories : Genetic Engineering and Molecular Biology
      Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE