Showing 2 results for Spatial Learning
Nasser Naghdi, Nahid Majlessi,
Volume 4, Issue 1 (1-2000)
Abstract
Data on the effects of serotonin reuptake inhibitors on learning and memory processes are not consistent. In the present study, the effects of citalopram, a very potent and completely selective inhibitor of the serotonin reuptake on spatial discrimination in the T-maze and Morris water maze, were assessed in mice and/or rats. Animals received different doses of citalopram (1, 2, 4, 8 or 16 mg/kg, i.p.) or its vehicle (saline) 30 min before training each day. The results showed no significant effects of citalopram on T-maze discrimination task in mice and rats. However, there was dose-dependent increases in latencies to find the invisible platform and traveled distances in citalopram received groups compared to the control group with the peak effect at doses of 4 and 8 mg/kg in Morris task. Therefore, it appears that citalopram can cause learning deficits in complex spatial tasks.
Gisou Mohaddes, Nasser Naghdi, Saeed Khamnei, Shohreh Khatami, Ali Haeri,
Volume 13, Issue 1 (1-2009)
Abstract
Background: Sex steroids and their receptors exist in hippocampus and affect spatial learning and memory. This study was designed to measure testosterone level of CA1 and to assess the effect of spatial learning on its amount in left and right hippocampus of adult male rats. Methods: Sixteen rats were divided into two intact and castrated groups, and then trained in Morris water maze (MWM). Another 40 animals were divided into four groups and their right or left hippocampus cannulated. Half of the animals in each group were castrated simultaneously. All the animals were trained in MWM. Microdialysis was performed and steroid contents of hippocampal dialysate were analyzed through HPLC/ultraviolet detection device method. Results: Results showed no significant differences between control and castrated animals in spatial learning after four days of training. Gonadectomy did not change testosterone level in CA1 region of hippocampus. Spatial learning decreased testosterone levels in CA1 region of hippocampus in right hippocampus of the non-castrated group. Significant differences were indicated in testosterone level between left and right hippocampus, in favor of left side in all groups. Conclusion: Castration does not affect learning. Testosterone, as a neuromodulator, exists in CA1 region of hippocampus and training can decrease its level only in right hippocampus significantly. Lesser testosterone content of right hippocampus may show the conversion of it to other metabolites.
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