Serotonin transport and synthesis systems during early development of invertebrates: functional analysis on a bivalve model. Short communication.

Serotonin (5.HT) is known to be functionally active during early development in both vertebrates and invertebrates. However, the presence of 5-HT and its synthesis and transport system has not yet been demonstrated in bivalve early development. The presence of 5-HT was immunochemically demonstrated at the cleavage stage of bivalve Mytilus trossulus. 5-HT level dramatically increased within all embryonic cells after incubation with 5-HTP but not after incubation with tryptophan and 5-HT. The first 5-HT uptake by specific transporter was detected at 13 hpf blastula stage only and it was restricted to one distinct cell.