central interaction of ascorbic acid and d2 dopamine receptors on spatial learning and memory in adult male rats

previous studies had reported that extracellular levels of ascorbic acid have modulatory effects on dopamine receptors. both ascorbic acid and dopamine receptor have an important role in learning and memory processes. however, the central interaction between ascorbic acid and dopamine d2 receptor on spatial learning and memory has not yet been elucidated. all experiments were carried out on male wistar rats. animals were subjected to 5 days of training in the morris water maze (mwm) task; 4 days with an invisible platform to test special learning and the 5th day with a visible platform to test motivation and sensorimotor coordination. the data showed that ascorbic acid (25 µg, i.c.v.) could improve spatial learning and memory indices. administration of bromocriptine, a d2 agonist, increased the effect of ascorbic acid, while treatment with the selective d2 antagonist sulpiride resulted in prevention of the ascorbate-induced memory consolidation. these results indicate that dopamine d2 receptors may be involved in ascorbic acid-induced learning and memory impairment.