ENDOGENOUS 24H-VARIATION OF ANTIOXIDANT ENZYMES IN THE PREFRONTAL CORTEX OF YOUNG AND AGED RATS

PONCE IT; KLUSCH, E; CORIA LUCERO, C; DEVIA, C; GIMÉNEZ TI; DELGADO SM; ANZULOVICH AC

Estancia Grande (San Luis)

Congreso; XXXII Reunion Anual de la Soc. de Biol. de Cuyo; 2014

Sociedad de Biología de Cuyo

Prefrontal cortex plays a key role in memory and learning and is especially susceptible to oxidative stress. Particularly, aging is associated to increased oxidative stress and altered circadian rhythms. It is known, the molecular clock activity is closely dependent on the cellular redox state. The objectives of this study were to investigate whether catalase (CAT) and glutathione peroxidase (GPx) expression and activity display endogenous rhythms in the rat prefrontal cortex (PFC) and to assess the consequences of aging on those temporal patterns. Holtzman rats from young (3-month-old) and aged (22-month-old) groups were maintained under constant darkness conditions, during 10 days before the experiment. Serum TBAR?s levels were measured by a colorimetric assay. CAT and GPx mRNA and enzymatic activity were determined by RT-PCR and kinetic assays, respectively, in PFC samples isolated every 4 h during a 24h period. As expected, we observed an increase in the 24h TBAR?s levels in the serum of aged rats. Antioxidant enzymes expression and activity vary significantly throughout a day under constant darkness conditions in the rat PFC. Aging abolished CAT and GPx 24h-variation. Loss of the 24h-variation of antioxidant enzymes in the PFC would modify the circadian oscillation of the cellular redox state and, consequently, the endogenous clock activity, in the PFC.