[Reverse absorption of serotonin by synaptosomes and its level in the rat cerebral cortex in acute and chronic...

Acute stress was simulated in Wistar rats by means of uncontrolled electric shock within 6 hrs; chronic stress, after the first 6-hr course, was developed within 9 days using 1-h daily treatment. Within 18 hrs of the acute stress occurring concentration of serotonin was decreased 2-fold in tissues of brain cortex, while reverse absorption of the neurotransmitter in synaptosomes was increased 3-fold. Under conditions of chronic stress concentration of serotonin tend to increase, whereas reverse absorption by nerve endings was decreased, which appear to occur due to brain adaptation to chronic stress.