Effects of chronic administration of norharman on spatial learning and memory in female rats

  Background: The exogenous and endogenous β-carbolines , and some of their metabolites have a stimulating effect on the dopaminergic system. β-carbolines can also improve learning and memory while increase hippocampal dopamine levels and dendritic and synaptic proliferation .   Objective: The aim of this study was to investigate the effects of chronic administration of norharman on spatial learning and memory in rats.   Methods: In this experimental study, 48 f emale wistar rats were randomly divided into control, alchohol and 4 norharmane groups. The control group were received no treatment. In alchohol and norharman groups, rats were received 0.2 ml alchohol or 1, 2, 3 or 4 mg/kg norharman intraperitoneally for 5 days before tests and 5 days during tests. All rates were tested for spatial learning and memory in the Morris water maze. Data were analyzed using student T-test, one way ANOVA and LSD as post hoc test. Findings: N orharman improved spatial learning in a dose dependent manner. T he difference between the 4 mg/kg norharman group and the control group was statistically significant in the 2nd day . N orharman also improved spatial memory in which lower doses improved spatial memory more than higher doses. T he difference between the 2 mg/kg and 4 mg/kg norharman groups was statistically significant.   Conclusion: With regards to the results, norharman as an endogenous bioactive molecule, might have a key role in the modulation of learning and memory functions.