Influences of aspartate on circadian patterns of lipid peroxidation products and antioxidants in Wistar rats.

INTRODUCTION The aim of the present study was to demonstrate the effects of aspartate on the circadian patterns of lipid peroxidation products and antioxidants in aspartate-treated rats, in order to investigate the influences of aspartate and whether it could modulate these rhythms differently, since aspartate is an important excitatory neurotransmitter (present in retinohypothalamic tract and suprachiasmatic nuclei [SCN]) involved in the generation and regulation of circadian rhythmicity. METHODS Aspartate (50 mg/kg body weight) was administered orally for 60 days to Wistar rats, and 24-hour rhythms of thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase were studied under semi-natural (light/dark 12:12 hr) conditions. RESULTS Exogenous aspartate administration caused acrophase advances in TBARS rhythms, and delays in GSH, SOD and catalase rhythms; altered MESOR and decreased amplitude values were also seen in all of these rhythms. CONCLUSION Our findings indicate that the orally-treated aspartate could reach the hypothalamus, and various brain centres possibly including SCN, and could modulate the circadian patterns of lipid peroxidation products and antioxidants.