the effect of bilateral intrahippocampal injection of all–trans retinoic acid on spatial learning in adult male rats.

introduction: previous studies have shown that vitamin a and its derivatives such as retinoid and all-trans retinoic acid have a crucial role in memory, learning and synaptic plasticity. the receptors of vitamin a are seen in different parts of the brain such as hippocampus, where vitamin a has an important role in learning. in this study, the effect of intrahippocampal (ca1) injection of all – trans retinoic acid on spatial learning was investigated in adult male rats. methods: 49 adult male rats divided in 7 groups were used. test groups (1 – 4) received 1μl of all – trans retinoic acid dissolved in dmso at concentrations of 1, 2, 4 and 8 μg/μl, for 4 consecutive days, 90 minutes before training. group 5 received dmso and 6th and 7th groups were designated as sham operation and control (intact) group, respectively. after each injection, morris water maze (mwm) was used as a method to measure learning task. results: this study showed that all – trans retinoic acid at the concentration of 1 μg/μl improved spatial learning in morris water maze (p< 0.05). conclusion: our findings show that all – trans retinoic acid improves spatial learning in rats via enhancing the expression of learning related proteins.