Immobilization and Light-Dark Cycle-Induced Modulation of Serotonin Metabolism in Rat Brain and of Lymphocyte Subpopulations: In vivo Voltammetric and FACS Analyses

The effect of immobilization and light-dark cycle on the serotoninergic system of the n. raphe dorsalis and on the distribution of blood lymphocyte subpopulations was studied in the rat. As was shown by in vivo voltammetry, 10 min immobilization enhanced serotonin metabolism with a maximum 15 min after immobilization. The distribution of the blood lymphocytes into subpopulations was also affected: pan-T and T helper lymphocytes were reduced during immobilization and reached minimum values after 20 min recovery. The circadian rhythms of serotonin metabolism and the distribution of pan-T and T helper cells exhibited a slight phase shift if compared with each other.