The Effect of Intrahippocampal Injection of Ascorbic Asid on Spatial Learning and Memory in Adult Male Rats

Ascorbic acid (AA) is present in high concentrations with heterogeneous distribution in the mammalian brain. Previous studies have shown that release of various neurotransmitters such as glutamate, acetylcholine and dopamine might be involved in the central AA release. On the other hand all of these neurotransmitters and the region CA1 of the hippocampus are involved in learning and memory. The aim of the present study was to evaluate the effects of ascorbic acid injection in the CA1 region on spatial learning and memory in adult male rats. 42 adult male NMRI rats (250-300 g) divided into 6 groups were used in this study. They included control group that received no injection, sham-operated group that received normal saline injection as vehicle and four groups that received different doses of ascorbic acid (6, 12, 24 and 48 μg/rat). All injections were given in 5 consecutive days and 30 min after each injection, the rats were tested in the Morris Water Maze test to measure learning and memory task. Spatial learning and memory parameters were subjected to analysis of variance (ANOVA). The results indicated that intrahippocampal microinjection of AA (12 and 24 μg/rat) significantly increased some spatial learning and memory parameters such as escape latency and path length to reach the hidden platform. Our findings show that AA injection into the CA1 region has a negative effect on spatial learning and memory.