VITAMIN A DEFICIENCY MODIFIES THE CIRCADIAN EXPRESSION OF BDNF AND RC3 IN THE RAT HIPPOCAMPUS

GOLINI RS; PONCE IT; DELGADO SM; ANZULOVICH AC

Puerto Madryn

Congreso; 46th. Annual meeting SAIB; 2010

SAIB

A role for vitamin A has been established in phenomena related tocognitive function. Some evidence points out retinoids asregulators of clock activity through their nuclear receptors.Objectives: 1) to investigate circadian variation of the brainderivedneurotrophic factor (BDNF), Neurogranin (RC3) andCLOCK genes expression in the rat hippocampus, and 2) to assessthe effect of a vitamin A-deficient diet on the clock-controlledlocomotor activity and the oscillating patterns of Bdnf, Rc3 andclock genes. Male Holtzman rats from control and vitamin Adeficient(DE) groups were maintained under constant darknessduring 10 days before the experiment. Hippocampi were takenevery 4 h. Scanning of Bdnf and Rc3 gene regulatory region forRAREs and E-boxes was carried out using MatInspector(Genomatix). Rest-activity cycles were registered using theArchron system. RARá and RXRâ mRNA levels were quantifiedby Real-time PCR. Bdnf, Rc3, Bmal1 and Per1 transcript levels,were determined by RT-PCR and BMAL1 and PER1 protein levelsby immunoblotting. We observed Bdnf and Rc3 expression displaya circadian rhythmicity in the rat hippocampus. RXRâ mRNAlevels were reduced, nocturnal activity decreased and circadianrhythms of Bdnf and Rc3 expression were attenuated in the DEgroup following changes in BMAL1 levels.Supported by Grant R01-TW006974, NIH/FIC, USA.