Effect of administration of ascorbic acid and dopamine D2 receptors agonist in the hippocampal CA1 area on spatial learning and memory in adult male rats

Document Type: Full paper (Original article)

Authors

1 Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran; Kerman Neuroscience Research Center (KNRC), Kerman University of Medical Sciences, Kerman, Iran

2 Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran

Abstract

Previous studies have shown that ascorbic acid (AA) plays a crucial role in mammalian brain as a
vitamin and neuronal modulator. There is increasing evidence indicating that dopaminergic system and AA
could affect learning and memory processes. In addition, vitamin C acts as a dopamine antagonist in the
brain. The aim of the present study was to evaluate the intra-hippocampal co-administration of AA and
bromocriptine (Br), a dopamine D2 receptor agonist, on spatial memory and learning. Adult male rats were
trained in Morris Water Maze task. Intra-hippocampal injection was performed through an implanted cannula
in the CA1 region. Animals were divided into 12 experimental groups (n=7) including: control, AA (6, 12, 24
and 48 μg/rat), Br (0.5, 1, 2 and 2.5 μg/rat), AA plus Br (24 and 2 μg/rat), AA and Br related sham. The
results showed that injection of AA caused a significant decrease in both learning and spatial memory.
However, administration of Br alone or concomitant with AA caused a significant increase in learning and
spatial memory as compared to the control and AA groups. These findings indicate that AA could attenuate
the effects of D2 dopamine receptors agonist on spatial memory and learning.

Keywords