Repetitive treatment with serotonin modifies protein synthesis and protein phosphorylation in the central nervous system of Hirudo medicinalis.

Serotonin (5HT) is the neurotransmitter involved in some forms of short-term memory in the leech. Behavioral experiments have demonstrated that long-term memory requires new protein synthesis. With the aim of studying the molecular mechanism underlying memory processes in the leech, we have analyzed the effect of 5HT on protein synthesis and protein phosphorylation. Segmental ganglia of the leech central nervous system have been labeled, proteins have been separated by two-dimensional-electrophoresis and labeled proteins detected by autoradiography. Our findings indicate that repetitive treatment with 5HT produces either the persistence of phosphorylation or changes in protein synthesis in several proteins.