Interaction between ascorbic acid and dopamine D2 receptor in the nucleus accumbens shell in response to feeding

Abstract

The aim of the present study is to evaluate the effects of intra-accumbens administration of Ascorbic Acid (AA) and co-administration of D2 agonist, bromocriptine (Br) and the D2 antagonist sulpiride (Su) (8, 16 μg rat-1) with AA on feed intake in adult male rats. The rats (220-300 g) were divided into several groups for intra-accumbens injections: control (intact), sham AA (injected vehicle of ascorbic acid), ascorbic acid (10, 50, 250 μg rat-1), sham Br (injected vehicle of bromocriptine), bromocriptine (12.5, 25, 50 μg rat-1), sham Su (injected vehicle of sulpiride), sulpiride (4 and 16 μg rat-1), AA (50 μg rat-1) + Br (50 μg rat-1) and AA (50 μg rat-1) + Su (16 μg rat-1). After stereotaxic operation and passing one week recovery period, drugs were injected daily (volume = 1 μL) for four days. The intra-accumbens administration of ascorbic acid (10, 50, 250 μg rat-1) decreased feed intake. Intra-accumbens injection of D2 agonist bromocriptine (25, 50 μg rat-1) decreased feed intake. Co-administration of the AA (50 μg rat-1) also decreased feed intake. Administration of D2 antagonist sulpiride (8, 16 μg rat-1) increased food intake and co-administration of AA (50 μg rat-1) blocked this effect. These results suggest that AA can act within the Acb to decreases feed intake and it has an agonistic effect on feeding regulatory effects of D2 receptor. © 2009 Academic Journals Inc.