Intracerebroventricular injection of aggregated beta-amyloid (1-42) modifies the daily temporal organization of cognitive performance and antioxidant enzymes in the temporal cortex of the rat

MAYRA CORTEZ; DARIO RAMIREZ; BELEN CANGIANO; CINTHIA CORIA-LUCERO; ANDREA CASTRO; CARINA LEDEZMA; MARIA DELSOUC; MARILINA CASAIS; ANA ANZULOVICH; SANDRA GOMEZ-MEJIBA; LORENA NAVEGATORE-FONZO

Congreso; Free Radical Biology And Medicine; 2022

Alzheimer's dementia (AD) is a neurodegenerative disorderthat causes memory loss and dementia in older adults.Intracellular accumulation of A? causes disturbance in theantioxidant defense system and cognitive dysfunctions.Besides the loss of memory, Alzheimer's patients showdysfunction of the circadian rhythms. The objective of thiswork was to investigate the effects ofintracerebroventricular injection of A? (1–42) on 24 hpatterns of cognitive performance and antioxidant defensesin the rat temporal cortex. Four-month-old male Holtzmanrats divided into the group's control (CO) and A?-injected(A?), were maintained under 12 h-light:12h-dark conditionsand received water and food ad-libitum. Temporal cortexsamples were isolated every 6 h during a 24 h period. Wefound that total antioxidant capacity and antioxidantenzyme activity displayed day-night oscillations in the rattemporal cortex. Spatial memory performance also variedwith the circadian clock. Intracerebroventricular injectionof A? (1-42) modified temporal patterns of cognitiveperformance as well as daily profiles of antioxidantparameters. Thus, an elevated A? peptide level inducesalterations in the daily rhythmicity of the antioxidantdefense system and, consequently, might affect cellularclock activity, thus affecting the spatial memoryperformance in AD.doi: 10.1016/j.freeradbiomed.2022.10.059