CIRCADIAN PATTERNS OF BDNF AND TrkB EXPRESSION ARE MODIFIED IN THE PREFRONTAL CORTEX OF AGED RATS

CORIA LUCERO C; PIGNATARO, V; PONCE, I; DEYURKA N; ANZULOVICH AC; NAVIGATORE FONZO LS

Jornada; XXXII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2014

During aging, brain undergoes several changes which begin with alterations in gene expression. The brain-derived neurotrophic factor (BDNF), its receptor TrkB and the cAMP response element binding protein (CREB) regulate a wide range of functions, such as synaptic plasticity and long-term potentiation, and are expressed in different regions, including prefrontal cortex. Previously, we howed circadian rhythmicity of BDNF and TrkB expression is abolished in the ippocampus of aged rats. In this work, our objectives were: to investigate hether BDNF, TrkB and CREB expression also displays an endogenous circadian rhythm in the rat prefrontal cortex, and to evaluate the consequences of aging on those temporal patterns. Young (3-month old) and aged (22-month old) Holtzman rats were maintained under 12hdark:12hdark (constant darkness) conditions, during 10 days before the experiment. Prefrontal cortex samples were isolated every 4 h during a 24h period. Regulatory regions of BDNF and TrkB genes were scanned for CRE sites, by using a bioinformatic tool. BDNF, TrkB and CREB mRNA levels were determined by RT-PCR. As expected, CRE sites were found in the BDNF and TrkB regulatory regions. BDNF and TrkB expression display an endogenously-controlled temporal variation in the rat prefrontal cortex, which is attenuated in the aged group, probably, as a consequence of alteration in the 24h variation of CREB expression.