INFLUENCE OF SEROTONIN ON PLANARIAN PHOTORECEPTORS’ REGENERATION

The paper presents data on the effect of biogenic amine, serotonin, on morphogenetic processes in planarians Schmidtea mediterranea and Girardia tigrina(Turbellaria, Platyhelminthes). For the study, cut-off median and tail fragments of the planarian body were used, in which eye regeneration was observed. Photoreceptor recovery occurred from the 3rd to the 6th day of regeneration. In experimental specimens exposed to serotonin at a concentration of 0.1–1 μM, acceleration of the photoreceptor regeneration process was observed. The stimulating effect was observed at 4–5 days after surgery. Planaria (Turbellaria, Platyhelminthes) are free-living flatworms related to parasitic trematodes, cestodes and monogenges. In addition to the nervous, muscular, digestive, excretory and reproductive systems, they have a pair of simple eyes (photoreceptors), so they can distinguish the intensity and direction of the light flux and are oriented in space [1]. Planarium eyes are located on the dorsal surface of the head part of the body and consist of photoreceptor and pigment cells that form an "eye cup". Planaria can regenerate the whole organism from a small fragment. In the process of regeneration, the planarium can completely restore the head ganglion (brain), as well as other organs, including the eyes.Our task was to study the dynamics of photoreceptor differentiation in planarians Schmidtea mediterranea, and to investigate the possible morphogenetic function of serotonin in S. mediterranea and G. tigrina