The role of serotonin in regulation of the circadian rhythms of locomotor activity in the cricket ( Acheta domesticus L.) I. Circadian variations in serotonin concentration in the brain and hemolymph

Abstract

1. Investigations were made on 24 hr of 5-hydroxytryptamine (5-HT) level in the brain and hemolymph of crickets reared under LD 12:12 conditions. 2. It was shown that serotonin level in the brain and hemolymph of crickets varies over the course of 24-hr. 3. The highest 5-HT level in the brain and hemolymph was found at 07.00 hr; the lowest at 19.00 hr in the case of brain, and at 24.00 hr in hemolymph.