Comparison of the Effect of Co-Injection of Ascorbic Acid and D2 Agonist (Bromocriptine) with Ascorbic Acid in Nucleus Accumbens Shell on Male Rat's Anxiety

Ascorbic acid (AA) is present in the most part of central nervous system (CNS) such as nucleus accumbens shell (Acbsh). Previous studies have shown that peripheral injection of AA can reduce anxiety. So the effect of intra-accumbens injection of AA، bromocriptine، and co-administration AA and bromocriptine (Br) on anxiety behavior of rats were investigated by Elevated plus maze (EPM).

In this study، 70 adult male Wistar rats (220-270 g) were used in 10 groups: control (intact)، sham AA (injected normal saline as AA vehicle)، AA (12، 24 and 48 µg/rat/side)، sham Br، Br (12. 5 and 25 µg/rat/side)، AA plus Br (24 and 25 µg/rat)، and sham AA plus Br. After surgery and recovery period، drugs were injected (volume= 1µl). Thirty minutes after each injection anxiety parameters (time percent in open arm and closed arm) were measured for 5 min by EPM task.

The result showed that Intra-accumbens injection of AA (24 µg/side/rat) (223. 28±15. 24)، (48 µg/side/rat) (248. 74±12. 57) (p<0. 001)، Br (12. 5 µg/side/rat) 235. 87±17. 45 (p<0. 001) and (25 µg/side/rat) 175. 57±20. 89 (p<0. 05) combined injection 228. 24±15. 99 (p<0. 001) significantly increased percentage of time spent in open arm in comparison with control.

We concluded that intra-accumbens injection of both AA and Br D2 receptor agonist as well as their co-administration induced significant decrease in anxiety behavior، dose dependent or dose independent manner.