Orexin A content in brain structures correlates with behavioral patterns in stressed rats
The aim of this investigation was to reveal correlations between some behavioral patterns and orexin concentrations in the brain structures in rats after an acute psychoemotional stress. A group of rats was placed into a chamber with a tiger python for 25 mi nutes and then as a treatment these rats received orexin A or its antagonist SB-408124 administered intranasally for 7 days. Then the quantitive indexes of behavioral patterns in open field and elevated plus maze were registered. The orexin A level was investigated in the brain structures (amygdala, hippocampus, hypothalamus) of such rats by means of high-sensitive ELISA. The correlations were assessed with Spearman’s rank correlation test. As a result, a correlation between orexin A content in the amygdala and hypothalamus and a number of ambulations (line crossings) characterizing motor activity in open field test has been revealed. Therefore, the level of orexin A in the amygdala and hypothalamus demonstrates a direct and reverse link with locomotor activity of rats respectively. Also a correlation between orexin A level in the hippocampus and amygdala and the time of staying in the dark alleys of the elevated plus maze has been revealed. So, the content of orexin A in the hippocampus and amygdala reflects anxiety level of a rat. It is concluded there is a positive correlation between the orexin A content in the limbic structures of the brain and emotional behavior of rats.