DAILY OSCILLATION OF BDNF AND ITS RECEPTOR (TrkB) EXPRESSION IS MODIFIED IN THE HIPPOCAMPUS BY AN I.C.V. INJECTION OF AMYLOID BETA PEPTIDE

PIGNATARO VERONICA ; CORIA LUCERO; LEDESMA CARINA; RAGUSSA V; ANZULOVICH, ANA CECILIA; NAVIGATORE FONZO, LORENA

San Luis

Congreso; XXXII Reunión Anual de la Sociedad de Biologia de Cuyo; 2014

Sociedad de Biologia de Cuyo

Alzheimer's disease (AD) is a neurodegenerative disorder. Elevated levels of β-amyloid peptide (Aβ) in the brain and progressive cognitive impairment are characteristics of AD. Besides the cognitive deficit, AD patients also show alterations in their circadian rhythms. Brain-derived neurotrophic factor (BDNF) is involved in learning and memory process by binding to its main functional receptor (TrkB). Previously, we showed circadian rhythmicity of BDNF and TrkB expression is abolished in the hippocampus of aged rats. The objective of this study was to investigate the effects of an i.c.v. injection of Aβ(40-42) peptide on the Aβ protein levels itself as well as on the 24h rhythms of BDNF and TrkB expression, in the rat hippocampus. Four-month-old males Holtzman rats were used in this study. Groups were defined as: control (CO) and Aβ-injected (Aβ). Rats were maintained under 12h-light:12h-dark conditions before the sacrifice. BDNF and Trkb mRNA levels were determined by RT-PCR and Aβ protein was analyzed by immunoblotting, in hippocampus samples isolated every 6 h throughout a 24h period. We found i.c.v. injection of Aβ(40-42) increased Aβ peptide content and attenuated daily variation of BDNF and TrkB expression in the rat hippocampus. Thus, Aβ peptide accumulation might disrupt temporal expression patterns in a brain area related to memory and learning, such as the hippocampus