절망행동모형에 의한 흰쥐 대뇌의 Fos 발현의 증가

Increased Fos Expression Behavioral Despair in Rat Brain

Many investigators have tried to identify the neurobiochemical mechanism of behavioral despair in an animal model of depression. However, there have been inconsistent findings on the mechanism of behavioral despair so far. Recently, it has been reported that immunochemistry might be one optimal method to demonstrate behavioral despair in terms of molecular aspects. In this context this study was designed to investigate the cerebral anatomical location of c-fos expression and elucidate the mechanism possibly associated with behavioral despair by assaying c-fos protein (Fos) with immunocytochemistry detection in rat brain. The animals were divided into behavioral despair (n = 10)，simple forced swimming (n = 10)， and control groups (n = 10), respectively. Fos immunoreactivity was measured by cell counts in specific brain regions. The results were as follows ； 1. The mean immobilization time in behavioral despair group (152 土 34.9 seconds) was significantly longer than that in simple forced swimming group (52.5 土 12.9 seconds, p 〈 0.01). 2. The numbers of cell exhibiting Fos immunoreactivity in regions of lateral septal nucleus and paraventricular nucleus in behavioral despair group were significantly higher than those in simple forced swimming group and in controls, respectively (p 〈0.05). 3. Behavioral despair group also showed significantly higher numbers of immunoreactivity cell in anterior hypothalamus, medial prefrontal cortex than that of control groups (p 〈 0.05). However, there was no significant difference of Fos immunoreactive cell counts in anterior hypothalamus and medial prefrontal cortex between simple forced swimming and control groups. In light of our results, it seems likely that behavioral despair , an animal model of depression, might induce Fos immunoreactivity differently from simple forced swimming