Vitamin A Deficiency the Circadian Expression of BDNF and RC3 in the Rat Hippocampus

GOLINI R, PONCE IT, DELGADO SM, ANZULOVICH AC

Puerto Madryn, Chubut

Congreso; XLVI Reunión anual de la Sociedad Argentina de investigación Bioquímica y Biología Molecular (SAIB); 2010

SAIB

A role for vitamin A has been established in phenomena related to cognitive function. Some evidence points out retinoids as regulators of clock activity through their nuclear receptors. Objectives: 1) to investigate circadian variation of the brain-derived neurotrophic factor (BDNF), Neurogranin (RC3) and CLOCK genes expression in the rat hippocampus, and 2) to assess the effect of a vitamin A-deficient diet on the clock-controlled locomotor activity and the oscillating patterns of Bdnf, Rc3 and clock genes. Male Holtzman rats from control and vitamin A-deficient (DE) groups were maintained under constant darkness during 10 days before the experiment. Hippocampi were taken every 4 h. Scanning of Bdnf and Rc3 gene regulatory region for RAREs and E-boxes was carried out using MatInspector (Genomatix). Rest-activity cycles were registered using the Archron system. RARá and RXRâ mRNA levels were quantified by Real-time PCR. Bdnf, Rc3, Bmal1 and Per1 transcript levels, were determined by RT-PCR and BMAL1 and PER1 protein levels by immunoblotting. We observed Bdnf and Rc3 expression display a circadian rhythmicity in the rat hippocampus. RXRâ mRNA levels were reduced, nocturnal activity decreased and circadian rhythms of Bdnf and Rc3 expression were attenuated in the DE group following changes in BMAL1 levels. (Supported by Grant R01-TW006974, NIH/FIC, USA).