The effects of L-DOPA, serotonin, reserpine and chlorpromazine on the daily rhythm of fluorescent intensity in leucocytes and blood platelets.

1. The rhythmic fluctuation of fluorescent intensity of leucocytes and platelets of rats was modified by the administration of some drugs such as L- DOPA, serotonin, reserpine and chlorpromazine. Timing of administration was determined to get clearcut results. The different results were expected by the administration of drugs at the other time of day. 2) The administration of L-DOPA enhanced the fluorescent intensity of leucocytes and platelets, and the tincture of them tended strongly to be green at 4 to 10 h after the treatment. The administration of serotonin suppressed the fluorescent intensity of leucocytes temporarily, but inversely enhanced the intensity of platelets significantly. Reserpine and chlorpromazine had a similar suppressive effect on the fluorescent intensity of leucocytes and platelets within 30 h after the treatment. Compared with them, the influence of reserpine was stronger than that of chlorpromazine. 3) In fact, these drugs made an marked influence on the rhythmic fluctuation of fluorescence intensity in leucocytes and platelets, but the physiological rhythmicity was remained in the ground of modified fluctuation of rats which were treated by those drugs.