The Alterations of The Diurnal Variations of Brain Tryptophan, Biogenic Amines and 5-Hydroxyindole Aceticacid In The Rat Under Limited Time Feeding

Abstract

The diurnal rhythms of Tryptophan (TRY), Serotonin (5-HT), 5-Hydroxyindoleacetic acid (5-HIAA), Dopamine (DA) and Norepinephrine (NE) endogenous levels were determined over a 24-hour period in two parts of the brain of rats maintained on a 12/12 light-darkness schedule.

Significant alterations of these rhythms when rats are given an access to food and water limited to the day-light hours are described. This suggests that other factors than light may affect biological rhythms.

The problem of biological time series analysis and the significance of our results in relation to brain biogenic amines metabolism and to sleep rhythmicity are discussed.