?Characterization of serotonin as a potential neurotransmitter in Echinococcus spp.

CAMICIA F.; SIMONETTA, SH; BIANCHI JI; PRADA, L.; KAMENETZKY, L.; MACCHIAROLI, N.; CUCHER, M.; ROSENZVIT, M.

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2012

The putative role of serotonin (5-HT; 5-hydroxytryptamine) as a neurotransmitter was evaluated in Echinococcus spp. The bioinformatics analysis in the recently available Echinococcus spp. genomes suggests the presence of genes encoding for proteins involved in 5-HT biosynthesis and two 5-HT receptors 5-HT (GPCR type). However, the genes encoding for proteins involved in 5-HT metabolism and the 5-HT ligand gated ionic channel, could not be identified. The serotoninergic inmunoreactivity (5-HT IR) was found in different stages of the parasite Echinococcus granulosus, showing an overall increase in fluorescence with the generation of new structures when the protoscolex differentiates towards the pre-adult stage and a progressive atrophy when the parasite develops into the pre-microcyst stage. The putative neurotransmitter showed a significant effect in protoscolex motility, showing maximal activity at 1 μM decreasing its effects at lower and higher concentrations. Other molecule, glutamate, an excitatory amino acid, was without effects tested at the same concentrations. Citalopram, a 5-HT reuptake inhibitor, blocked the worm motility induced by 5-HT, however the drug ondansetron, a 5-HT gated ionic channel inhibitor didn´t affect the worm motility. Overall, the results strongly suggest the presence of 5-HT and a neuronal role of this molecule. The 5-HT pathway could be exploited in the future for the development of new anthelmintic drugs.