Impairment of blood-brain barrier (BBB) in rat by immobilization stress: role of serotonin (5-HT).

Influence of immobilization stress on blood-brain barrier (BBB) was studied in rats using Evans blue as barrier tracer. 7-9 hr of of immobilization had increased the permeability of BBB mainly in younger rats. This increased permeability was significantly reduced with p-CPA, indomethacin or vinblastine pretreatment. Theophylline treatment caused early extravasation of Evans blue dye. The increased level of serotonin in immobilization and infusion of 5-HT in model experiments suggest a causative role of serotonin in the increased permeability of BBB induced by immobilization stress.